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Pseudo-topotactic conversion of carbon nanotubes into one-dimensional carbon nanowires is a challenging but feasible path to obtain desired diameters and morphologies. Here, a previously predicted but experimentally unobserved carbon allotrope, T-carbon, has been produced from pseudo-topotactic conversion of a multi-walled carbon nanotube suspension in methanol by picosecond pulsed-laser irradiation. The as-grown T-carbon nanowires have the same diameter distribution as pristine carbon nanotubes, and have been characterized by high-resolution transmission electron microscopy, fast Fourier transform, electron energy loss, ultraviolet–visible, and photoluminescence spectroscopies to possess a diamond-like lattice, where each carbon is replaced by a carbon tetrahedron, and a lattice constant of 7.80 Å. The change in entropy from carbon nanotubes to T-carbon reveals the phase transformation to be first order in nature. The computed electronic band structures and projected density of states are in good agreement with the optical absorption and photoluminescence spectra of the T-carbon nanowires. T-carbon is a previously predicted but so far unobserved allotrope of carbon, with a crystal structure similar to diamond, but with each atomic lattice position replaced by a carbon tetrahedron. Here, the authors produce T-carbon nanowires via laser-irradiating a suspension of carbon nanotubes in methanol.

Cariogenic Streptococcus mutans is known as a predominant etiological agent of dental caries due to its exceptional capacity to form biofilms. From strains of S. mutans isolated from dental plaque, we discovered, in the present study, a polyketide/nonribosomal peptide biosynthetic gene cluster, muf , which directly correlates with a strong biofilm-forming capability. We then identified the muf -associated bioactive product, mutanofactin-697, which contains a new molecular scaffold, along with its biosynthetic logic. Further mode-of-action studies revealed that mutanofactin-697 binds to S. mutans cells and also extracellular DNA, increases bacterial hydrophobicity, and promotes bacterial adhesion and subsequent biofilm formation. Our findings provided an example of a microbial secondary metabolite promoting biofilm formation via a physicochemical approach, highlighting the importance of secondary metabolism in mediating critical processes related to the development of dental caries. The mutanofactin family of lipopeptide natural products, produced by strains of cariogenic Streptococcus mutans , promotes biofilm formation via increased cell-surface hydrophobicity and binding to extracellular DNA.

This study adopted nanosecond laser to conduct drilling research on nickel-based alloy with thermal barrier coatings (TBCs). The experiments of different processing environments on quality and efficiency of laser drilling were conducted. Through combination of high processing efficiency under air environment and good processing quality under water environment, temporal control of air/water environment on laser drilling is proposed. Since drilling efficiency was not significantly reduced, cold machining effect of water was used to improve processing quality. Research results proved that laser processing method with temporal control of air/water environment has advantages of traditional laser drilling under air and water. Laser drilling of temporal control of air/water environment was improved in quality in comparison with single environment.

Semiconductor-based gas sensors are of great interest in both industrial and research settings, but poor selectivity has hindered their further development. Current efforts including doping, surface modifications and facet controlling have been proved effective. However, the “methods-selectivity” correlation is ambiguous because of uncontrollable defects and surface states during the experiments. Here, as a case study, using a DFT method, we studied the adsorption features of commonly tested gases—CH2O, H2, C2H5OH, CH3COCH3, and NH3—on facets of ZnO(0001¯), ZnO(101¯0) and ZnO(101¯1). The adsorption energies and charge transfers were calculated, and adsorption selectivity was analyzed. The results show ZnO(0001¯) has obvious CH2O adsorption selectivity; ZnO(101¯0) has a slight selectivity to C2H5OH and NH3; and ZnO(101¯1) has a slight selectivity to H2, which agrees with the experimental results. The mechanism of the selective adsorption features was studied in terms of polarity, geometric matching and electronic structure matching. The results show the adsorption selectivity is attributed to a joint effort of electronic structure matching and geometric matching: the former allows for specific gas/slab interactions, the latter decides the strength of the interactions. As the sensing mechanism is probably dominated by gas–lattice interactions, this work is envisioned to be helpful in designing new sensing material with high selectivity.

Cariogenic Streptococcus mutans is known as a predominant etiological agent of dental caries due to its exceptional capacity in forming biofilms. From strains of S. mutans isolated from dental plaque, we here discover a polyketide/non-ribosomal peptide biosynthetic gene cluster, muf, which directly correlates with a strong biofilm-forming capability. We then identify the muf-associated bioactive product, mutanofactin-697 that contains a novel molecular scaffold, along with its biosynthetic logic. Further mode-of-action studies reveal mutanofactin-697 binds to S. mutans cells nonspecifically, increases bacterial hydrophobicity, and promotes bacterial adhesion and subsequent biofilm formation. Our findings provide the first example of a microbial secondary metabolite promoting biofilm formation via a physicochemical approach, highlighting the significance of secondary metabolism in mediating critical processes related to the development of dental caries. Competing Interest Statement The authors have declared no competing interest.

ObjectiveThis study aimed to characterise the clinical features and treatment regimens of patients with lupus who have lymphadenopathy (LAP), as well as to investigate the presence and potential implications of Langerhans cells (LCs) infiltration in lymph nodes.MethodsA case-control study was conducted to identify the clinical characteristics of newly diagnosed, treatment-naïve patients with lupus who have LAP. Lymph node biopsies were performed, and LC infiltration was assessed using immunohistochemical staining for S100, CD1a and Langerin.ResultsA total of 59 patients with SLE who have LAP (SLE-LAP) were enrolled, with 81 patients with SLE without LAP serving as controls. The SLE-LAP group exhibited significantly higher frequencies of fever (64.4% vs 35.8%, p<0.001), anaemia (71.2% vs 42.0%, p<0.001), serous effusion (27.1% vs 11.1%, p=0.015), myositis (10.2% vs 1.2%, p=0.045) and elevated CRP levels (44.1% vs 22.2%, p=0.006). Moreover, autoantibodies, including anti-Smith (37.3% vs 16.0%, p=0.004), anticardiolipin IgG (27.1% vs 11.1%, p=0.015), IgM (42.4% vs 9.9%, p<0.001) and IgA (8.5% vs 0.0%, p=0.027), were more frequently detected in the LAP group. LC infiltration was confirmed in 29 of the 59 lymph node biopsies (49.2%). Immunohistochemical analysis revealed a scattered (58.6%) or focal (41.4%) distribution of LCs. Patients with LC infiltration predominantly presented with fever (72.4%), anaemia (64.3%), skin rashes (62.1%) and arthritis (62.1%). However, no significant differences in clinical manifestations were observed between LC-positive and LC-negative patients.ConclusionLC infiltration in the lymph nodes of patients with SLE is relatively common and should be carefully evaluated to prevent misdiagnosis. The role of LCs in the autoimmune response and pathogenesis of SLE warrants further investigation.