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Two-dimensional materials and their combined heterostructures have paved the way for numerous next-generation electronic and optoelectronic applications. Herein, we performed first principles calculations to computationally design the MoSe2/WS2 heterostructure and consider its geometric structure, electronic properties and contact behavior, as well as the effects of the electric fields and strain. Our results show that the MoSe2/WS2 heterostructure is energetically, thermodynamically and mechanically stable. Depending on the stacking configurations, the MoSe2/WS2 heterostructure could form type-I or type-II band alignment. The versatility in contact behavior makes the MoSe2/WS2 heterostructure attractive in electronics and optoelectronics. The combination of the MoSe2/WS2 heterostructure also leads to an enhancement in the adsorption efficiency and the carrier mobility compared with the constituent components. More interestingly, our findings demonstrate that the electric field can induce the transition between type-I and type-II band alignments, as evident by the experimental measurement [J. Kistner-Morris, A. Shi, E. Liu, T. Arp, F. Farahmand, T. Taniguchi, K. Watanabe, V. Aji, C. H. Lui and N. Gabor, Nat. Commun., 2024, 15, 4075]. Additionally, we also find that strain can also induce the transition between type-I and type-II band alignments and lead to the transition from semiconductor to metal in the MoSe2/WS2 heterostructure. Our findings prove that the MoSe2/WS2 heterostructure holds significant potential for developing next-generation electronics. [ABSTRACT FROM AUTHOR]

Objective: Sjögren disease (SjD) is an autoimmune condition characterized by the dysfunction of the salivary and lacrimal glands. The study aimed to decipher the pathogenic cell populations and their immunologic pathways in the salivary glands. We further determined the therapeutic effect of inhibiting dedicator of cytokinesis 2 (DOCK2) shared by novel clusters of CD8+ T cells in an SjD mouse model. Methods: This study employed single‐cell RNA sequencing to examine the composition and dynamics of immune cells in the salivary glands of SjD mice. By analyzing the transcriptomic data and employing clustering analysis, a specific target was identified, leading to the treatment of mice with a targeted inhibitor. Results: The results showed diverse immune cell types, including B cells, CD4+ T cells, CD8+ T cells, macrophages, and natural killer cells. We identified specific clusters possessing phenotypic characteristics of immune cell subpopulations, thereby showing specific genes/pathways associated with the disease. The most striking finding was the elevated expression of DOCK2 in CD8+ T cells in the SjD model. This discovery is significant because subsequent treatment with a DOCK2 inhibitor 4‐[3‐(2‐Chlorophenyl)‐2‐propen‐1‐ylidene]‐1‐phenyl‐3,5‐pyrazolidinedione (CPYPP) led to a marked amelioration of SjD signs. Conclusion: The effectiveness of DOCK2 inhibition in alleviating SjD signs highlights the potential of DOCK2 as a therapeutic target, opening new avenues for treatment strategies that could modulate the immune response more effectively in SjD. [ABSTRACT FROM AUTHOR]

Recently, the assembly of van der Waals heterostructures (vdWH) has proved to be an effective strategy to alter the properties and enhance the functionality of multifunctional devices based on 2D materials. Herein, first‐principles calculations are employed to construct the HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ vdWH, exploring its electronic properties, contact characteristics, and the impact of electric gating. The HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ vdWH is predicted to be structurally, thermally, and mechanically stable. The HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ vdWH leads to a reduction in the bandgap compared to the constituent components, potentially enhancing optical absorption. Furthermore, the HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ heterostructure forms the type‐II band alignment, localizing electrons and holes predominantly in the HfS2${\rm HfS}_2$ and MoS2${\rm MoS}_2$ layers, respectively. Such type‐II HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ heterostructure makes it promising candidate for the optoelectronic devices, benefiting from the spatial separation of photogenerated electron‐hole pairs. Notably, the electronic properties and contact characteristics of the HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ vdWH are controllable under electric gating. The negative electric gating facilitates to a transformation from type‐II to type‐I band alignment, while the positive electric field induces a shift from semiconductor to metal in the HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ vdWH. This findings can provide valuable insights into the fundamental aspects that contribute to the exceptional performance observed in HfS2${\rm HfS}_2$/MoS2${\rm MoS}_2$ vdWH toward high‐performance multifunctional devices. [ABSTRACT FROM AUTHOR]

The functionality of electronic and optoelectronic devices relying on two‐dimensional (2D) materials can be substantially influenced by the characteristics of their electrical contacts. Herein, a metal–semiconductor electrical contact between metallic NbS2 and semiconducting MoSe2 monolayer is constructed using first‐principles calculations. The electronic properties and contact characteristics of the NbS2/MoSe2 heterostructure as well as the effects of electric fields and in‐plane strains are also explored. These results indicate that the NbS2/MoSe2 heterostructure exhibits the p$p$‐type Schottky contact (ShC) with low Schottky barriers and possesses low contact resistance of the tunneling barrier. Furthermore, the electronic properties and contact characteristics of the NbS2/MoSe2 heterostructure can be fine‐tuned through the application of in‐plane strains and electric fields. The electric fields give rise to the transformation from p$p$‐type to n$n$‐type ShC as well as the conversion from ShC to Ohmic contact (OhC) in the NbS2/MoSe2 heterostructure. Similarly, in‐plane strains play a role in direct‐to‐indirect band gap transitions and further contribute to the conversion from ShC to OhC in the NbS2/MoSe2 heterostructure. These findings offer valuable theoretical insights that can guide the practical utilization of the NbS2/MoSe2 vdW‐MSH in the development of next‐generation electronic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

A significant problem in the area of rechargeable alkali ion battery technologies is the exploration of anode materials with overall high specific capacities and superior physical properties. By using first-principles calculations, we have determined that monolayer TiSi2N4 is precisely such a potential anode candidate. Its demonstrated dynamic, thermal, mechanical, and energetic stabilities make it feasible for experimental realization. An important benefit of the electrode conductivity is that the electronic structure reveals that the pristine system experiences a change from a semiconductor to a metal throughout the entire alkali adsorption process. What's more interesting is that monolayer TiSi2N4 can support up to double-sided 3-layer ad-atoms, resulting in extremely high theoretical capacities for Li, Na, Mg, and K of 1004, 854, 492 and 531 mA h g−1 and low average open-circuit voltages of 0.55, 0.25, 0.55, and −1.3 V, respectively. Alkali diffusion on the surface has been demonstrated to occur extremely quickly, with migration energy barriers for Li, Na, Mg, and K as low as 0.25, 0.14, 0.10, and 0.07 eV, respectively. The results reveal that the migration barrier energy is the lowest for Li and Mg from path-2 and Na and K from path-1. Overall, these findings suggest that monolayer TiSi2N4 is a suitable anode candidate for use in high-performance and low-cost metal-ion batteries. [ABSTRACT FROM AUTHOR]

Recently, by forming a P‐rich P–S system, the P3S monolayer has been predicted to have good resistance to air oxidation, large band gap, high absorption, and superior mobility. Inheriting this prediction, a series of ternary Janus P6XY (X/Y = S, Se, and Te; X ≠ Y) monolayers based on P3X nanosheet are designed and studied. The structures of P6XY monolayers are confirmed to be stable based on the evaluation of calculated results for phonon spectra, ab initio molecular dynamic simulations. It is also found that P6XY compounds possess anisotropic mechanical characteristics. All Janus structures are indirect semiconductors with large energy gaps varying from 2.12 to 2.60 eV calculated by the hybrid functional. Besides, biaxial strain significantly affects the electronic properties of the P6XY monolayers. In particular, the biaxial strains can induce a transition from indirect to direct bandgap in all three P6XY structures. The carrier mobility in the three proposed structures exhibits directional anisotropy and high electron mobility value, up to 1.27 × 103 cm2 V−1 s−1, which are suitable for applications in high‐performance and direction‐dependent nanoelectronic devices. [ABSTRACT FROM AUTHOR]

In this Letter, the structural, mechanical, electronic, and transport properties of two-dimensional (2D) ternary Janus Si 2 X Y (X / Y = S, Se, Te) monolayers are studied based on the calculations using first-principles density functional theory. All three structures are found as direct semiconductors with moderated bandgap energies and good stabilities for experimental synthesis. The transport properties are also examined by calculating the carrier mobilities. We find that the carrier mobilities of all three monolayers are anisotropic not only between the electrons and holes but also between the two transport directions. The Si2SSe monolayer exhibited the highest electron mobility of 897.66 cm2 V−1 s−1 in the x axis. Amazingly, our calculations reveal that the Si 2 X Y monolayers are auxetic materials with negative Poisson's ratio along both x and y axes. Particularly, the Si2SSe has the largest negative Poisson's ratio value of –0.131 in the x direction. These obtained results open more prospects for advanced applications of these materials in electronics, optoelectronics, and nanomechanics. [ABSTRACT FROM AUTHOR]

In this study, we construct new 2D Janus MGeSN2 (M = Ti, Zr, and Hf) monolayers and systematically investigate their electronic band structures under applied biaxial strain. Their crystal lattice and electronic as well as transport properties are also examined based on the first-principles calculations and deformation potential theory. The results show that the MGeSN2 structures have good dynamical and thermal stability, and their elastic constants satisfy the criteria of Born–Huang also indicating the good mechanical stability of these materials for experimental synthesis. Our calculated results indicate that the TiGeSN2 monolayer exhibits indirect-bandgap semiconductor characteristics whereas the ZrGeSN2 and HfGeSN2 monolayers exhibit direct-bandgap semiconductor characteristics. Importantly, the biaxial strain shows significant influences on the electronic energy band structures of the monolayers in the presence of a phase transition from semiconductor to metal, which is an important feature of these materials for their application in electronic devices. All three structures exhibit anisotropic carrier mobility in both x and y transport directions, suggesting their great potential for application in electronic devices. [ABSTRACT FROM AUTHOR]

T cell receptors (TCR) play a vital role in the immune system's ability to recognize and respond to foreign antigens, relying on the highly polymorphic rearrangement of TCR genes. The recognition of autologous peptides by adaptive immunity may lead to the development and progression of autoimmune diseases. Understanding the specific TCR involved in this process can provide insights into the autoimmune process. RNA-seq (RNA sequencing) is a valuable tool for studying TCR repertoires by providing a comprehensive and quantitative analysis of the RNA transcripts. With the development of RNA technology, transcriptomic data must provide valuable information to model and predict TCR and antigen interaction and, more importantly, identify or predict neoantigens. This review provides an overview of the application and development of bulk RNA-seq and single-cell (SC) RNA-seq to examine the TCR repertoires. Furthermore, discussed here are bioinformatic tools that can be applied to study the structural biology of peptide/TCR/MHC (major histocompatibility complex) and predict antigenic epitopes using advanced artificial intelligence tools. [ABSTRACT FROM AUTHOR]

Novel Janus materials have attracted broad interest due to the outstanding properties created by their out-of-plane asymmetry, with increasing theoretical exploration and more reports of successful fabrication in recent years. Here, we construct and explore the crystal structures, stabilities, electronic band structures, and transport properties – including carrier mobilities – of two-dimensional Janus MGeSiP4 (M = Ti, Zr, or Hf) monolayers based on density functional theory calculations. From the cohesive energies, elastic constants, and phonon dispersion calculations, the monolayers are confirmed to exhibit structural stability with high feasibility for experimental synthesis. All the structures are indirect band-gap semiconductors with calculated band-gap energies in the range of 0.77 eV to 1.01 eV at the HSE06 (Heyd–Scuseria–Ernzerhof) level. Interestingly, by applying external biaxial strain, a semiconductor to metal phase transition is observed for the three Janus structures. This suggests potential for promising applications in optoelectronic and electromechanical devices. Notably, the MGeSiP4 monolayers show directionally anisotropic carrier mobility with a high electron mobility of up to 2.72 × 103 cm2 V−1 s−1 for the ZrGeSiP4 monolayer, indicating advantages for applications in electronic devices. Hence, the presented results reveal the novel properties of the 2D Janus MGeSiP4 monolayers and demonstrate their great potential applications in nanoelectronic and/or optoelectronic devices. This investigation could stimulate further theoretical and experimental studies on these excellent materials and motivate further explorations of new members of this 2D Janus family. [ABSTRACT FROM AUTHOR]

The construction of van der Waals heterostructures have been extensively studied for the design of new devices for potential applications in nanotechnology and renewable energy. In this work, we perform first-principles calculations to explore the electronic structure, optical properties and photocatalytic performance of the SiS/BSe heterostructure. The SiS/BSe heterostructure is energetically and thermally stable in the ground state. The generation of the SiS/BSe heterostructure gives rise to a reduction in the band gap compared to the constituent monolayers, suggesting that the optical absorption of such a heterostructure can be enlarged. Furthermore, the formation of the SiS/BSe heterostructure leads to generation of type-II band alignment, which makes the heterostructure a promising candidate for photogenerated charge separation and light detection purposes. The absorption spectrum demonstrates broadening and red-shift in the SiS/BSe heterostructure. Additionally, the SiS/BSe heterostructure possesses suitable band edges and straddles the standard redox potentials, thus making it a potential candidate for photocatalytic water dissociation under solar light irradiation. These findings pave the way for practical applications of the SiS/BSe heterostructure for optoelectronics and photocatalytic applications. [ABSTRACT FROM AUTHOR]

The generation of layered heterostructures from a combination of two or more different two-dimensional (2D) materials is considered as a powerful strategy to modify the electronic properties of 2D materials and enhance their performance in devices. Herein, using first-principles calculations, we systematically study the electronic properties and the band alignment in a heterostructure formed from 2D boron phosphide (BP) and silicane (SiH) monolayers. The BP/SiH heterostructure is structurally and mechanically stable in the ground state. The generation of the BP/SiH heterostructure leads to a reduction in the band gap, thus enhancing the optical absorption coefficient compared to the constituent BP and SiH monolayers. In addition, the BP/SiH heterostructure has a high carrier mobility of 3.2 × 104 cm2 V−1 s−1. Furthermore, the combined BP/SiH heterostructure gives rise to the formation of a type-II band alignment, inhibiting the recombination of the photogenerated carriers. The electronic properties and band alignment of the BP/SiH heterostructure can be tuned by an applied external electric field, which causes a reduction in the band gap and leads to the transition of the band alignment from type-II to type-I. Our findings could act as theoretical guidance for the use of the BP/SiH heterostructure in the design of high-efficiency nanodevices. [ABSTRACT FROM AUTHOR]

COVID-19 is caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). The severity of COVID-19 is highly variable and related to known (e.g., age, obesity, immune deficiency) and unknown risk factors. The widespread clinical symptoms encompass a large group of asymptomatic COVID-19 patients, raising a crucial question regarding genetic susceptibility, e.g., whether individual differences in immunity play a role in patient symptomatology and how much human leukocyte antigen (HLA) contributes to this. To reveal genetic determinants of susceptibility to COVID-19 severity in the population and further explore potential immune-related factors, we performed a genome-wide association study on 284 confirmed COVID-19 patients (cases) and 95 healthy individuals (controls). We compared cases and controls of European (EUR) ancestry and African American (AFR) ancestry separately. We identified two loci on chromosomes 5q32 and 11p12, which reach the significance threshold of suggestive association (p<1x10-5 threshold adjusted for multiple trait testing) and are associated with the COVID-19 susceptibility in the European ancestry (index rs17448496: odds ratio[OR] = 0.173; 95% confidence interval[CI], 0.08–0.36 for G allele; p = 5.15× 10−5 and index rs768632395: OR = 0.166; 95% CI, 0.07–0.35 for A allele; p = 4.25×10−6, respectively), which were associated with two genes, PPP2R2B at 5q32, and LRRC4C at 11p12, respectively. To explore the linkage between HLA and COVID-19 severity, we applied fine-mapping analysis to dissect the HLA association with mild and severe cases. Using In-silico binding predictions to map the binding of risk/protective HLA to the viral structural proteins, we found the differential presentation of viral peptides in both ancestries. Lastly, extrapolation of the identified HLA from the cohort to the worldwide population revealed notable correlations. The study uncovers possible differences in susceptibility to COVID-19 in different ancestral origins in the genetic background, which may provide new insights into the pathogenesis and clinical treatment of the disease. [ABSTRACT FROM AUTHOR]

Stacking different two-dimensional materials to generate a vertical heterostructure has been considered a promising way to obtain the desired properties and improve device performance. Here, in this work, using first principles calculations, we design a vertical heterostructure by stacking graphene (GR) and silicane (SiH) and investigate the electronic properties and electrical contact in the GR/SiH heterostructure as well as the possibility of tuning these properties under an external electric field and vertical strain. The GR/SiH heterostructure is structurally and mechanically stable at the equilibrium interlayer separation. The GR/SiH heterostructure exhibits a p-type Schottky contact with a small Schottky barrier of 0.43 eV, presenting great tunability of the electrical contact from Schottky to Ohmic contact under different conditions. The external electric field not only leads to a transition from the p-type to n-type Schottky contact but also induces a transformation from a Schottky contact to Ohmic one. Furthermore, changing the interlayer separation can be considered a useful tool to regulate the Schottky barriers and electric contact in the GR/SiH heterostructure, which is prominent for constructing electronic devices. Our findings could provide an effective tool for the design of high-performance nanoelectronic devices based on the GR/SiH heterostructure. [ABSTRACT FROM AUTHOR]

Since the recent successful experimental synthesis of MoSi2N4 [Science, 369 (2020), 670], the "MA2Z4 family" has been of particular interest to the scientists in the field of materials science due to its outstanding physical properties. In this paper, the first‐principles calculations are performed to study the structural, elastic, and electronic properties of novel two‐dimensional (2D) Janus MSiGeN4 monolayers (M = Ti, Zr, Hf). The calculations of phonon spectra indicate that monolayers MSiGeN4 are dynamically stable and can be experimentally synthesized. The obtained Young's modulus and Poisson's ratio of the Janus structures MSiGeN4 are much larger than that of other binary 2D materials and meet the mechanical stability criteria suggested by Born and Huang. In the calculations using either PBE or HSE06 functionals, the Janus MSiGeN4 structures exhibit indirect semiconductor characteristics with larger band gaps than that of similar septuple‐atomic‐layer materials, such as MoSiGeN4 and WSiGeN4. In addition, the influences of biaxial strain and external electric field on the electronic structure of MSiGeN4 are investigated. It is found that the biaxial strain tunes the electronic characteristics more significantly than the external electric field. The obtained results can provide insights into novel Janus monolayers with potential applications in electronic devices. [ABSTRACT FROM AUTHOR]

The C57BL/6.NOD-Aec1Aec2 mouse has been extensively studied to define the underlying cellular and molecular basis for the onset and development of Sjögren's syndrome (SS), a human systemic autoimmune disease characterized clinically as the loss of normal lacrimal and salivary gland functions leading respectively to dry eye and dry mouth pathologies. While an overwhelming majority of SS studies in both humans and rodent models have long focused primarily on pathophysiological events and the potential role of T lymphocytes in these events, recent studies in our murine models have indicated that marginal zone B (MZB) lymphocytes are critical for both development and onset of SS disease. Although migration and function of MZB cells are difficult to study in vivo and in vitro, we have carried out ex vivo investigations that use temporal global RNA transcriptomic analyses to track early cellular and molecular events in these exocrine glands of C57BL/6.NOD-Aec1Aec2 mice. In the present report, genome-wide transcriptome analyses of lacrimal glands indicate that genes and gene-sets temporally upregulated during early onset of disease define the Notch2/NF-kβ14 and Type1 interferon signal transduction pathways, as well as identify chemokines, especially Cxcl13, and Rho-GTPases, including DOCK molecules, in the cellular migration of immune cells to the lacrimal glands. We discuss how the current results compare with our recently published salivary gland data obtained from similar studies carried out in our C57BL/6.NOD-Aec1Aec2 mice, pointing out both similarities and differences in the etiopathogeneses underlying the autoimmune response within the two glands. Overall, this study uses the power of transcriptomic analyses to identify temporal molecular bioprocesses activated during the preclinical covert pathogenic stage(s) of SS disease and how these findings may impact future intervention therapies as the disease within the two exocrine glands may not be identical. [ABSTRACT FROM AUTHOR]