Perovskite solar cells (PSCs) based on the regular n–i–p device architecture have reached above 25% certified efficiency with continuously reported improvements in recent years. A key common factor ...for these recent breakthroughs is the development of SnO2 as an effective electron transport layer in these devices. In this article, the key advances in SnO2 development are reviewed, including various deposition approaches and surface treatment strategies, to enhance the bulk and interface properties of SnO2 for highly efficient and stable n–i–p PSCs. In addition, the general materials chemistry associated with SnO2 along with the corresponding materials challenges and improvement strategies are discussed, focusing on defects, intrinsic properties, and impact on device characteristics. Finally, some SnO2 implementations related to scalable processes and flexible devices are highlighted, and perspectives on the future development of efficient and stable large‐scale perovskite solar modules are also provided.
This review summarizes the recent advances of SnO2‐based perovskite solar cells (PSCs) and the related interface optimization strategies and applications. The fundamental properties of SnO2 are discussed, with a focus on the defect chemistry, and various preparation methods for improving SnO2 and SnO2/perovskite interface. Finally, the challenges and opportunities for further development of SnO2‐based PSCs are provided.
Recurrent cancer that spreads to distant sites is the leading cause of disease-related death among cancer patients. Cancer cells are likely to disseminate during cancer progression, and some may ...enter dormancy, remaining viable but not increasing. These dormant cancer cells (DCCs) are rarely detectable with current diagnostic systems. Moreover, they can interpret homoeostatic signals from the microenvironment, thereby evading immune surveillance and chemotherapy. Eventually, DCCs can reawaken in response to signals, which are not yet fully understood, resulting in recurrence and metastasis. Therefore, understanding the biology of DCC reawakening is key to preventing metastasis. Over the last decade, a growing body of literature has revealed the mechanisms involved in cancer dormancy and reawakening. The cytotoxic activity of immune cells can cause cancer cells to enter a dormant state, and chronic inflammation can reactivate cancer proliferation at distant sites. Upon the binding of circulating DCCs to extracellular molecules, various signaling cascades are activated and reinitiate cell proliferation. In the present review, we attempt to consolidate the existing literature to provide a framework for the understanding of this crucial step in cancer progression.
Although there have been attempts to use non‐lead based halide perovskite materials as insulating layers for resistive switching memory, the ratio of low resistance state (LRS) to high resistance ...state (HRS) ( = ON/OFF ratio) and/or endurance is reported to be mostly lower than 103. Resistive switching memory characteristics of layered (BzA)2CuBr4 (BzA = C6H5CH2NH3) perovskite with high ON/OFF ratio and long endurance are reported here. The X‐ray diffraction (XRD) pattern of the deposited (BzA)2CuBr4 layer shows highly oriented (00l) planes perpendicular to a Pt substrate. An Ag/PMMA/(BzA)2CuBr4/Pt device shows bipolar switching behavior. A forming step at around +0.5 V is observed before the repeated bipolar switching at the SET voltage of +0.2 V and RESET voltage of ‐0.3 V. The ON/OFF ratio as high as =108 is monitored along with an endurance of ≈2000 cycles and retention time over 1000 s. The high ON/OFF ratio enables multilevel storage characteristics as confirmed by changing the compliance currents. Ohmic conduction at the LRS and Schottky emission at HRS are involved in electrochemical metallization process. The bipolar resistive switching property is retained after storing the device at ambient condition under relative humidity of about 50% for 2 weeks, which indicates that (BzA)2CuBr4 is stable memory material.
The layered (BzA)2CuBr4 (BzA = C6H5CH2NH3) perovskite is developed for an environmentally friendly multilevel data storage memristor, which exhibits a stable bipolar switching behavior at the SET voltage of +0.2 V and RESET voltage of −0.3 V, leading to ON/OFF ratio as high as 108 and endurance of 2000 cycles.
The Hippo tumor suppressor pathway, which is well conserved from
Drosophila
to humans, has emerged as the master regulator of organ size, as well as major cellular properties, such as cell ...proliferation, survival, stemness, and tissue homeostasis. The biological significance and deregulation of the Hippo pathway in tumorigenesis have received a surge of interest in the past decade. In the current review, we present the major discoveries that made substantial contributions to our understanding of the Hippo pathway and discuss how Hippo pathway components contribute to cellular signaling, physiology, and their potential implications in anticancer therapeutics.
Post-treatment of a perovskite film is known to be an efficient way to passivate surface defects in perovskite solar cells (PSCs). Conventionally, post-treatment with organic iodides has been ...performed on the annealed perovskite phase (abbreviated as APP-PT) which, however, forms undesirable excess iodides on the surface that can generate interstitial iodine defects causing poor stability. Here, we report an efficient post-treatment process that is performed on the as-deposited un-annealed intermediate phase (abbreviated as UIP-PT). This method enables an effective passivation of the perovskite film surface with a minimal organic iodide passivation agent (100-fold reduced concentration compared with the conventional method) to prevent the surplus iodides. The trap density (
n
t
) of the perovskite film is substantially decreased from 1.62 × 10
16
cm
−3
(untreated sample) to 1.24 × 10
16
cm
−3
after UIP-PT, while little change in
n
t
is observed for the conventional method (
n
t
= 1.41 × 10
16
cm
−3
). Furthermore, negligible current-voltage hysteresis is observed in the UIP-PT sample because of the increased activation energy for ion migration. As a result of suppressed ion migration and the reduced traps, the device based on the UIP-PT demonstrates improved stability in the dark and under illumination, maintaining 96.37% of the initial PCE after 1750 h of storage.
Post-treatement of an unannealed perovskite film is found to be more efficienct way to passivate defects of perovskite solar cells.
we assessed the performance of the optimization algorithms by comparing volumetric modulated arc therapy generated by a progressive resolution optimized (VMAT
) and photon optimizer (VMAT
) in terms ...of plan quality, MU reduction, sparing of the spinal cord (or cauda equina), and plan complexity.
Fifty-seven patients who received spine stereotactic ablative radiotherapy (SABR) with tumors located in the cervical, thoracic, and lumbar spine were retrospectively selected. For each patient, VMAT
and VMAT
with two full arcs were generated with using the PRO and PO algorithms. For dosimetric evaluation, the dose-volumetric (DV) parameters of the planning target volume (PTV), organs at risk (OARs), the corresponding planning organs at risk (PRV), and 1.5-cm ring structure surrounding the PTV (Ring
) were calculated for all VMAT plans. The total number of monitor units (MUs) and the modulation complexity score for the VMAT (MCS
) were compared. To investigate the correlations of OAR sparing to plan complexity, Pearson's and Spearman's correlation tests were conducted between the two algorithms (PO - PRO, denoted as Δ) in the DV parameters for normal tissues, total MUs, and MCS
.
For the PTVs, Target conformity and dose homogeneity in the PTVs of VMAT
were better than those of VMAT
with statistical significance. For the spinal cords (or cauda equine) and the corresponding PRVs, all of the DV parameters for VMAT
were markedly lower than those for VMAT
, with statistical significance (all p < 0.0001). Among them, the difference in the maximum dose to the spinal cord between VMAT
and VMAT
was remarkable (9.04 Gy vs. 11.08 Gy with p < 0.0001). For Ring
, no significant difference in V
for VMAT
and VMAT
was observed.
The use of VMAT
resulted in improved coverage and uniformity of dose to the PTV, as well as OARs sparing, compared with that of VMAT
for cervical, thoracic, and lumbar spine SABR. Better dosimetric plan quality generated by the PRO algorithm was observed to result in higher total MUs and plan complexity. Therefore, careful evaluation of its deliverability should be performed with caution during the routine use of the PRO algorithm.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this paper, we consider a network reconstruction problem using unmanned aerial vehicles (UAVs) where stationary ad hoc networks are severely damaged in a post-disaster scenario. The main objective ...of this paper is to repair the network by supplementing aerial wireless links into the isolated ground network using UAVs. Our scheme performs network probing from the air and finds out crucial spots where both local and global routing performance can significantly be recovered if deployed. First, we propose a novel distributed coverage path planning algorithms with independent and computationally lightweight navigation based on adaptive zigzag patterns. Second, we present route topology discovery schemes that capture both local and non -local network connectivity by extracting inherent route skeletons via stitching partial local paths obtained from the simple packet probing by UAVs. Finally, we find the optimal UAV relay deployment positions that can improve network-wide data delivery most effectively based on three novel approaches of an optimization technique, an iterative heuristic algorithm, and a topology partitioning of strongly connected component . Simulation results demonstrate that our distributed traversing algorithms reduce the complete coverage time, the travel distance, and the duplicate coverage compared to other counterpart algorithms. Our deployment algorithms recover severely impaired routes, incurring reasonable computational overhead.
Radiotherapy (RT) is a highly effective multimodal nonsurgical treatment that is essential for patients with advanced colorectal cancer (CRC). Nevertheless, cell subpopulations displaying intrinsic ...radioresistance survive after RT. The reactivation of their proliferation and successful colonization at local or distant sites may increase the risk of poor clinical outcomes. Recently, radioresistant cancer cells surviving RT were reported to exhibit a more aggressive phenotype than parental cells, although the underlying mechanisms remain unclear.
By investigating public databases containing CRC patient data, we explored potential radioresistance-associated signaling pathways. Then, their mechanistic roles in radioresistance were investigated through multiple validation steps using patient-derived primary CRC cells, human CRC cell lines, and CRC xenografts.
Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling was activated in radioresistant CRC tissues in correlation with local and distant metastases. JAK2 was preferentially overexpressed in the CRC stem cell subpopulation, which was accompanied by the phosphorylation of STAT proteins, especially STAT3. JAK2/STAT3 signaling played an essential role in promoting tumor initiation and radioresistance by limiting apoptosis and enhancing clonogenic potential. Mechanistically, the direct binding of STAT3 to the cyclin D2 (CCND2) promoter increased CCND2 transcription. CCND2 expression was required for persistent cancer stem cell (CSC) growth via the maintenance of an intact cell cycle and proliferation with low levels of DNA damage accumulation.
Herein, we first identified JAK2/STAT3/CCND2 signaling as a resistance mechanism for the persistent growth of CSCs after RT, suggesting potential biomarkers and regimens for improving outcomes among CRC patients.
The microbiome is vital for immune system development and homeostasis. Changes in microbial composition and function, termed dysbiosis, in the skin and the gut have recently been linked to ...alterations in immune responses and to the development of skin diseases, such as atopic dermatitis (AD). In this review, we summarize the recent findings on the gut and skin microbiome, highlighting the roles of major commensals in modulating skin and systemic immunity in AD. Although our understanding of the gut-skin axis is only beginning, emerging evidence indicates that the gut and skin microbiome could be manipulated to treat AD.
Hydrogen peroxide is involved in a variety of enzyme catalysis as an oxidant or toxic by‐product. Thereby, attenuation of the H2O2‐driven oxidative stress is one of the key issues for preparative ...biocatalysis. Here, a rational approach to improve the robustness of enzymes, in particular, Baeyer‐Villiger monooxygenases (BVMOs) against H2O2 was investigated. The enzyme access tunnels, which may serve as exit paths for H2O2 from the active site to the bulk, were predicted by using the CAVER and/or protein energy landscape exploration (PELE) software for the phenylacetone monooxygenase variant (PAMO_C65D) from Thermobifida fusca and the BVMO from Pseudomonas putida KT2440. The amino acid residues, which are susceptible to oxidation by H2O2 (e. g., methionine and tyrosine) and located in vicinity of the predicted H2O2 migration paths, were substituted with less reactive or inert amino acids (e. g., leucine and isoleucine). This led to design of the H2O2‐resistant enzyme variants, which became robust biocatalysts for synthetic applications. For instance, the H2O2‐resistant P. putida BVMO reached turnover numbers of 4,100 for the BV oxygenation of 4‐decanone, which is 2.8‐fold greater than the parent enzyme. Moreover, the H2O2‐resistant P. putida BVMO allowed 2‐fold enhancement in titer of 9‐(nonanoyloxy)nonanoic acid (8) formation in a cascade fatty acid biotransformation. Therefore, it was assumed that the CAVER/PELE‐based H2O2 migration path engineering represents an efficient rational design approach to improve not only oxidative stability but also biotransformation performance of the H2O2‐forming or utilizing enzymes (e. g., BVMOs, oxidases, and peroxidases).
PDF
