Double band inversion in the topological phase transition of Ge1-xSnx alloys

We use first-principles simulation and virtual crystal approximation to reveal the unique double band inversion and topological phase transition in Ge1-xSnx alloys. Wavefunction parity, spatial charge distribution and surface state spectrum analyses suggest that the band inversion in Ge1-xSnx is relayed by its first valence band. As the system evolves from Ge to {\alpha}-Sn, its conduction band moves down, and inverts with the first and the second valence bands consecutively. The first band inversion makes the system nontrivial, while the second one does not change the topological invariant of the system. Both the band inversions yield surface modes spanning the individual inverted gaps, but only the surface mode in the upper gap associates with the nontrivial nature of tensile-strained {\alpha}-Sn.Comment: 5 pages, 6 figure

The role of macrophages in gastric cancer

As one of the deadliest cancers of the gastrointestinal tract, there has been limited improvement in long-term survival rates for gastric cancer (GC) in recent decades. The poor prognosis is attributed to difficulties in early detection, minimal opportunity for radical resection and resistance to chemotherapy and radiation. Macrophages are among the most abundant infiltrating immune cells in the GC stroma. These cells engage in crosstalk with cancer cells, adipocytes and other stromal cells to regulate metabolic, inflammatory and immune status, generating an immunosuppressive tumour microenvironment (TME) and ultimately promoting tumour initiation and progression. In this review, we summarise recent advances in our understanding of the origin of macrophages and their types and polarisation in cancer and provide an overview of the role of macrophages in GC carcinogenesis and development and their interaction with the GC immune microenvironment and flora. In addition, we explore the role of macrophages in preclinical and clinical trials on drug resistance and in treatment of GC to assess their potential therapeutic value in this disease

The complete chloroplast genome of Cycas bifida, an extremely small population protected species

Cycas bifida (Dyer) K.D.Hill (2004) is an extremely small population-protected species of China. In this study, we reported the first chloroplast genome sequence of C. bifida. The chloroplast genome of C. bifida included two single-copy regions (large single-copy (LSC) and small single-copy (SSC)) and a pair of inverted repeats (IRs) regions comprising 88,946 bp, 23,107 bp, and 25,053 bp, respectively. The complete chloroplast genome of C. bifida contains 131 genes, including 86 protein-coding genes, 37 transfer RNA genes, and 8 ribosomal RNA genes. The overall GC content of the C. bifida chloroplast genome is 39.41%, and the LSC, SSC, and IR regions occupy 38.70%, 36.52%, and 42.02%, respectively. A phylogenetic analysis was performed based on complete chloroplast genomes from 15 species and found that C. bifida was closely related to Cycas szechuanensis W.C.Cheng & L.K.Fu

Atomic layer deposition of Co3O4 on carbon nanotubes/carbon cloth for high-capacitance and ultrastable supercapacitor electrode

Co3O4 nanolayers have been successfully deposited on a flexible carbon nanotubes/carbon cloth (CC) substrate by atomic layer deposition. Much improved capacitance and ultra-long cycling life are achieved when the CNTs@Co3O4/CC is tested as a supercapacitor electrode. The improvement can be from the mechanically robust CC/CNTs substrate, the uniform coated high capacitance materials of Co3O4 nanoparticles, and the unique hierarchical structure. The flexible electrode of CNTs@Co3O4/CC with high areal capacitance and excellent cycling ability promises great potential for developing high-performance flexible supercapacitors.ASTAR (Agency for Sci., Tech. and Research, S’pore)Accepted versio

Oxygen vacancies mediated ferromagnetism in hydrogenated Zn0.9Co0.1O film

Zn0.9Co0.1O films were prepared by pulsed laser deposition and followed by annealing treatment in hydrogen atmosphere. Both samples show ferromagnetic behavior and saturated ferromagnetic magnetization was significantly increased by five times after the hydrogenation treatment. Co ions in both samples have been confirmed to be bivalent as substituents. Moreover, hydrogenation did not change the ZnO wurtzite structure and no segregation of Co, Co oxides or any other secondary phases were detected. Furthermore, the Co 2p3/2 peaks shift to lower energy level after hydrogenation, excluding the formation of Co-H-Co complexes. The structural characterizations clearly confirmed that the increment of oxygen vacancies was due to the hydrogenation treatment. These results indicate that the oxygen vacancies play a crucial role in mediating the ferromagnetism in Zn0.9Co0.1O film

Selective adsorption of carbon dioxide by carbonized porous aromatic framework (PAF)

A series of carbonized PAF-1s were obtained with enhanced gas storage capacities and isosteric heats of adsorption (Qst for short). Especially, PAF-1-450 can adsorb 4.5 mmol g-1 CO2 at 273 K and 1 bar. Moreover, it also exhibits excellent selectivity over other gases. On the basis of single component isotherm data, the dual-site Langmuir-Freundlich adsorption model-based ideal adsorption solution theory (IAST) prediction indicates that the CO2/N2 adsorption selectivity is as high as 209 at a 15/85 CO2/N2 ratio. Also, the CO2/CH4 adsorption selectivity is in the range of 7.8-9.8 at a 15/85 CO2/CH4 ratio at 0 < p < 40 bar, which is highly desirable for landfill gas separation. The calculated CO2/H2 adsorption selectivity is about 392 at 273 K and 1 bar for 20/80 CO2/H2 mixture. Besides, these carbonized PAF-1s possess excellent physicochemical stability. Practical applications in capture of CO2 lie well within the realm of possibility

Atomic Layer Deposition of Aluminum Sulfide: Growth Mechanism and Electrochemical Evaluation in Lithium-Ion Batteries

This study describes the synthesis of aluminum sulfide (AlS_<i>x</i>) thin films by atomic layer deposition (ALD) using tris­(dimethylamido)aluminum and hydrogen sulfide. We employed a suite of in situ measurement techniques to explore the ALD AlS_<i>x</i> growth mechanism, including quartz crystal microbalance, quadrupole mass spectrometry, and Fourier transform infrared spectroscopy. A variety of ex situ characterization techniques were used to determine the growth characteristics, morphology, elemental composition, and crystallinity of the resultant AlS_<i>x</i> films. This study revealed that the AlS_<i>x</i> growth was self-limiting in the temperature range 100–250 °C, and the growth per cycle decreased linearly with increasing temperature from ∼0.45 Å/cycle at 100 °C to ∼0.1 Å/cycle at 250 °C. The AlS_<i>x</i> films were amorphous in this temperature range. We conducted electrochemical testing to evaluate the ALD AlS_<i>x</i> as a potential anode material for lithium-ion batteries (LIBs). The ALD AlS_<i>x</i> exhibited reliable cyclability over 60 discharge–charge cycles with a sustainable discharge capacity of 640 mAh/g at a current density of 100 mA/g in the voltage window of 0.6–3.5 V

Colorectal cancer–associated T cell receptor repertoire abnormalities are linked to gut microbiome shifts and somatic cell mutations

ABSTRACTAs with many diseases, tumor formation in colorectal cancer (CRC) is multifactorial and involves immune, environmental factors and various genetics that contribute to disease development. Accumulating evidence suggests that the gut microbiome is linked to the occurrence and development of CRC, and these microorganisms are important for immune maturation. However, a systematic perspective integrating microbial profiling, T cell receptor (TCR) and somatic mutations in humans with CRC is lacking. Here, we report distinct features of the expressed TCRβ repertoires in the peripheral blood of and CRC patients (n = 107) and healthy donors (n = 30). CRC patients have elevated numbers of large TCRβ clones and they have very low TCR diversity. The metagenomic sequencing data showed that the relative abundance of Fusobacterium nucleatum (F. nucleatum), Escherichia coli and Dasheen mosaic virus were elevated consistently in CRC patients (n = 97) compared to HC individuals (n = 30). The abundance of Faecalibacterium prausnitzii and Roseburia intestinalis was reduced in CRC (n = 97) compared to HC (n = 30). The correlation between somatic mutations of target genes (16 genes, n = 79) and TCR clonality and microbial biomarkers in CRC had been investigated. Importantly, we constructed a random forest classifier (contains 15 features) based on microbiome and TCR repertoires, which can be used as a clinical detection method to screen patients for CRC. We also analysis of F. nucleatum-specific TCR repertoire characteristics. Collectively, our large-cohort multi-omics data aimed to identify novel biomarkers to inform clinical decision-making in the detection and diagnosis of CRC, which is of possible etiological and diagnostic significance

Double band inversion in the topological phase transition of Ge

We use first-principles simulation and alchemical mixing approximation to reveal the unique double band inversion and topological phase transition in Ge$_{1-\mathit{x}}$ Sn$_{\mathit{x}}$ alloys. Wave function parity, spatial charge distribution and surface state spectrum analyses suggest that the band inversion in Ge$_{1-\mathit{x}}$ Sn$_{\mathit{x}}$ is relayed by its first valence band. As the system evolves from Ge to ${\alpha}$ -Sn, its conduction band moves down, and inverts with the first and the second valence bands consecutively. The first band inversion makes the system nontrivial, while the second one does not change the topological invariant of the system. Both of the band inversions yield surface modes spanning the individual inverted gaps, but only the surface mode in the upper gap associates with the nontrivial nature of tensile-strained ${\alpha}$ -Sn