Tungsten diselenide (WSe2) and related transition metal dichalcogenides exhibit interesting optoelectronic properties owing to their peculiar band structures originating from the valley degree of ...freedom. Although the optical generation and detection of valley polarization has been demonstrated, it has been difficult to realize active valley-dependent functions suitable for device applications. We report an electrically switchable, circularly polarized light source based on the material's valley degree of freedom. Our WSe2-based ambipolar transistors emit circularly polarized electroluminescence from p-i-n junctions electrostatically formed in transistor channels. This phenomenon can be explained qualitatively by the electron-hole overlap controlled by the in-plane electric field. Our device demonstrates a route to exploit the valley degree of freedom and the possibility to develop a valley-optoelectronics technology.
The photovoltaic effect in traditional p-n junctions-where a p-type material (with an excess of holes) abuts an n-type material (with an excess of electrons)-involves the light-induced creation of ...electron-hole pairs and their subsequent separation, generating a current. This photovoltaic effect is particularly important for environmentally benign energy harvesting, and its efficiency has been increased dramatically, almost reaching the theoretical limit
. Further progress is anticipated by making use of the bulk photovoltaic effect (BPVE)
, which does not require a junction and occurs only in crystals with broken inversion symmetry
. However, the practical implementation of the BPVE is hampered by its low efficiency in existing materials
. Semiconductors with reduced dimensionality
or a smaller bandgap
have been suggested to be more efficient. Transition-metal dichalcogenides (TMDs) are exemplary small-bandgap, two-dimensional semiconductors
in which various effects have been observed by breaking the inversion symmetry inherent in their bulk crystals
, but the BPVE has not been investigated. Here we report the discovery of the BPVE in devices based on tungsten disulfide, a member of the TMD family. We find that systematically reducing the crystal symmetry beyond mere broken inversion symmetry-moving from a two-dimensional monolayer to a nanotube with polar properties-greatly enhances the BPVE. The photocurrent density thus generated is orders of magnitude larger than that of other BPVE materials. Our findings highlight not only the potential of TMD-based nanomaterials, but also more generally the importance of crystal symmetry reduction in enhancing the efficiency of converting solar to electric power.
Active systems can produce a far greater variety of ordered patterns than conventional equilibrium systems. In particular, transitions between disorder and either polar- or nematically ordered phases ...have been predicted and observed in two-dimensional active systems. However, coexistence between phases of different types of order has not been reported. We demonstrate the emergence of dynamic coexistence of ordered states with fluctuating nematic and polar symmetry in an actomyosin motility assay. Combining experiments with agent-based simulations, we identify sufficiently weak interactions that lack a clear alignment symmetry as a prerequisite for coexistence. Thus, the symmetry of macroscopic order becomes an emergent and dynamic property of the active system. These results provide a pathway by which living systems can express different types of order by using identical building blocks.
The valley degree of freedom of electrons is attracting growing interest as a carrier of information in various materials, including graphene, diamond and monolayer transition-metal dichalcogenides. ...The monolayer transition-metal dichalcogenides are semiconducting and are unique due to the coupling between the spin and valley degrees of freedom originating from the relativistic spin-orbit interaction. Here, we report the direct observation of valley-dependent out-of-plane spin polarization in an archetypal transition-metal dichalcogenide--MoS2--using spin- and angle-resolved photoemission spectroscopy. The result is in fair agreement with a first-principles theoretical prediction. This was made possible by choosing a 3R polytype crystal, which has a non-centrosymmetric structure, rather than the conventional centrosymmetric 2H form. We also confirm robust valley polarization in the 3R form by means of circularly polarized photoluminescence spectroscopy. Non-centrosymmetric transition-metal dichalcogenide crystals may provide a firm basis for the development of magnetic and electric manipulation of spin/valley degrees of freedom.
Background: Patients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum ...and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms.
Patients and methods: We retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas.
Results: Complete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P<0.0001) but was comparable when restricted to stage IV cases (4.0 months, P=0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively.
Conclusion: The current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.
The importance of highly active mitochondria and their contribution to neuronal function has been of recent interest. In most cases, however, mitochondrial activity is estimated using measurements of ...mitochondrial inner membrane potential (IMP
), and little is known about the dynamics of native mitochondrial ATP (ATP
). This study conducted simultaneous imaging of IMP
and ATP
in neurons to explore their behaviour and their correlation during physiological mitochondrial/neuronal activity. We found that mitochondrial size, transport velocity and transport direction are not dependent on ATP
or IMP
. However, changes in ATP
and IMP
during mitochondrial fission/fusion were found; IMP
depolarized via mitochondrial fission and hyperpolarized via fusion, and ATP
levels increased after fusion. Because the density of mitochondria is higher in growth cones (GCs) than in axonal processes, integrated ATP
signals (density × ATP
) were higher in GCs. This integrated signal in GCs correlated with axonal elongation. However, while the averaged IMP
was relatively hyperpolarized in GCs, there was no correlation between IMP
in GCs and axonal elongation. A detailed time-course analysis performed to clarify the reason for these discrepancies showed that IMP
and ATP
levels did not always correlate accurately; rather, there were several correlation patterns that changed over time.
Histone deacetylases (HDACs) represent novel molecular targets for the treatment of various types of cancers, including multiple myeloma (MM). Many HDAC inhibitors have already shown remarkable ...antitumor activities in the preclinical setting; however, their clinical utility is limited because of unfavorable toxicities associated with their broad range HDAC inhibitory effects. Isoform-selective HDAC inhibition may allow for MM cytotoxicity without attendant side effects. In this study, we demonstrated that HDAC3 knockdown and a small-molecule HDAC3 inhibitor BG45 trigger significant MM cell growth inhibition via apoptosis, evidenced by caspase and poly (ADP-ribose) polymerase cleavage. Importantly, HDAC3 inhibition downregulates phosphorylation (tyrosine 705 and serine 727) of signal transducers and activators of transcription 3 (STAT3). Neither interleukin-6 nor bone marrow stromal cells overcome this inhibitory effect of HDAC3 inhibition on phospho-STAT3 and MM cell growth. Moreover, HDAC3 inhibition also triggers hyperacetylation of STAT3, suggesting crosstalk signaling between phosphorylation and acetylation of STAT3. Importantly, inhibition of HDAC3, but not HDAC1 or 2, significantly enhances bortezomib-induced cytotoxicity. Finally, we confirm that BG45 alone and in combination with bortezomib trigger significant tumor growth inhibition in vivo in a murine xenograft model of human MM. Our results indicate that HDAC3 represents a promising therapeutic target, and validate a prototype novel HDAC3 inhibitor BG45 in MM.
We present a review of methods for procedurally generating the morphology of virtual creatures. We include a range of methods, with the main groups being from ALife over art to video games. Even ...though at times these groups overlap, for clarity we have kept this distinction. By including the word virtual, we mean that we focus on methods for simulation in silico, and not physical robots. We also include a historical perspective, with information on methods such as cellular automata, L‐systems and a focus on earlier pioneers in the field.
Burn treatments are complex, and for this reason, a specialised multidisciplinary approach is recommended. Evaluating the quality of care provided to acute burn patients through quality indicators ...makes it possible to develop and implement measures aiming at better results. There is a lack of information on which indicators to evaluate care in burn patients. The purpose of this scoping review was to identify a list of quality indicators used to evaluate the quality of hospital care provided to acute burn patients and indicate possible aspects of care that do not have specific indicators in the literature.
A comprehensive scoping review (PRISMA-ScR) was conducted in four databases (PubMed, Cochrane Library, Embase, and Lilacs/VHL) between July 25 and 30, 2022 and redone on October 6, 2022. Potentially relevant articles were evaluated for eligibility. General data and the identified quality indicators were collected for each included article. Each indicator was classified as a structure, process, or outcome indicator.
A total of 1548 studies were identified, 82 were included, and their reference lists were searched, adding 19 more publications. Thus, data were collected from 101 studies. This review identified eight structure quality indicators, 72 process indicators, and 19 outcome indicators listed and subdivided according to their objectives.
This study obtained a list of quality indicators already used to monitor and evaluate the hospital care of acute burn patients. These indicators may be useful for further research or implementation in quality improvement programs.
Protocol was registered on the Open Science Framework platform on June 27, 2022 ( https://doi.org/10.17605/OSF.IO/NAW85 ).
We present high-resolution, H-band imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm ...imagery suggested the existence of a dust-depleted cavity at r < or =, slant 46 AU, our observations reveal the presence of scattered light components as close as 0".2 (~28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0".5 (~70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h ~ 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelength observations.
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