Search

The application of attention mechanisms, especially channel attention, has achieved huge success in the field of computer vision. However, existing methods mainly focus on more sophisticated attention modules for better performance, but ignore global and local contexts in the frequency domain. This work focuses on the channel relationship and proposes a novel architectural unit called Frequency Global and Local (FGL) context block. It adaptively recalibrates global-local channel-wise feature responses by explicitly modeling interdependencies between channels in the frequency domain. The proposed lightweight FGL module is efficient well generalizable across different datasets. Meanwhile, the FGL context block significantly improves the performance of existing convolutional neural networks (CNNs) at a slight computational cost. Our FGL module is extensively evaluated with applications of image classification, object detection, and semantic segmentation with the backbones of ResNets, MobileNetV2, and MobileNeXt. The experimental results indicate that our module is more efficient than its counterparts. Our model is open-sourced at https://github.com/YunDuanFei/FGL. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) have emerged as highly promising candidates for the next generation of photonics and optoelectronic devices, owing to their prominent optical and excitonic properties, as well as the convenience of fabrication. Particularly, ultrathin two-dimensional (2D) MHPs, which are generally prepared by exfoliation, solution growth, and chemical vapor deposition method, have attracted dramatically increasing attentions owing to their combined features of ultrathin 2D morphology and superior performance of MHPs. Despite the growing interest in ultrathin 2D MHPs, there is currently a lack of a comprehensive and systematic overview of the distinct advantages offered by each growth method for producing these materials. This review critically assesses the preliminary studies on the materials design and preparation of ultrathin MHPs. Furthermore, it explores heterostructures based on ultrathin MHPs and offers insights into the challenges and opportunities that lie ahead for this enticing class of 2D materials. [ABSTRACT FROM AUTHOR]

Checkpoint kinase 1 (CHK1) is critical for cell survival under replication stress (RS). CHK1 inhibitors (CHK1i's) in combination with chemotherapy have shown promising results in preclinical studies but have displayed minimal efficacy with substantial toxicity in clinical trials. To explore combinatorial strategies that can overcome these limitations, we perform an unbiased high-throughput screen in a non-small cell lung cancer (NSCLC) cell line and identify thioredoxin1 (Trx1), a major component of the mammalian antioxidant-system, as a determinant of CHK1i sensitivity. We establish a role for redox recycling of RRM1, the larger subunit of ribonucleotide reductase (RNR), and a depletion of the deoxynucleotide pool in this Trx1-mediated CHK1i sensitivity. Further, the TrxR inhibitor auranofin, an approved anti-rheumatoid arthritis drug, shows a synergistic interaction with CHK1i via interruption of the deoxynucleotide pool. Together, we show a pharmacological combination to treat NSCLC that relies on a redox regulatory link between the Trx system and mammalian RNR activity. The clinical application of inhibitors targeting checkpoint kinase 1 (CHK1) is challenged by limited efficacy. Here, the authors identify that thioredoxin (Trx) system inhibition mediates sensitivity to CHK1 inhibitor via regulating the activity of ribonucleotide reductase, demonstrating the synergistic effect of CHK1 inhibitor and inhibitors targeting Trx system in lung cancer models. [ABSTRACT FROM AUTHOR]

Conventional liquid-phase methods lack precise control in synthesizing and processing materials with macroscopic sizes and atomic thicknesses. Water interfaces are ubiquitous and unique in catalyzing many chemical reactions. However, investigations on two-dimensional (2D) materials related to water interfaces remain limited. Here we report the growth of millimeter-sized 2D PbI2 single crystals at the water-air interface. The growth mechanism is based on an inherent ion-specific preference, i.e. iodine and lead ions tend to remain at the water-air interface and in bulk water, respectively. The spontaneous accumulation and in-plane arrangement within the 2D crystal of iodide ions at the water-air interface leads to the unique crystallization of PbI2 as well as other metal iodides. In particular, PbI2 crystals can be customized to specific thicknesses and further transformed into millimeter-sized mono- to few-layer perovskites. Additionally, we have developed water-based techniques, including water-soaking, spin-coating, water-etching, and water-flow-assisted transfer to recycle, thin, pattern, and position PbI2, and subsequently, perovskites. Our water-interface mediated synthesis and processing methods represents a significant advancement in achieving simple, cost-effective, and energy-efficient production of functional materials and their integrated devices. Here, the authors report the growth of millimetre-scale 2D PbI2 single crystals via the spontaneous accumulation and in-plane arrangement of iodide ions at the water-air interface. The metal iodide crystals could be thinned down to a single monolayer via water etching, and subsequently converted into perovskite optoelectronic devices. [ABSTRACT FROM AUTHOR]

Using traditional materials to improve the permeability of silty soils can cause irreversible damage to the environment. Therefore, it is necessary to develop environmentally friendly biopolymers, such as xanthan gum (XG), to replace traditional materials to improve resistance to water erosion by reducing the permeability coefficient. In this study, a series of permeability tests and scanning electron microscope (SEM) tests were conducted on xanthan gum-improved silty soil (XGS). The variations in the permeability coefficient of XG-improved silty soil and the effects of initial dry density, XG-soil ratio, and curing age on the permeability were investigated. Test results show that the permeability coefficient of XGS decreased with the increase of initial dry density, XG-soil ratio, and curing age. With increasing the initial dry density, soil particles compressed against each other, decreasing the actual water flow crossing area, which leads to a decrease in the permeability coefficient. With the increase of the XG-soil ratio, the fill-blocking effect of xanthan gum with hydrogel connections becomes more and more obvious, which leads to a reduction in the permeability coefficient. Xanthan gum hydration takes time, and a lot of crystals are produced in XGS as the curing age increases; these crystals fill larger pores, resulting in the permeability coefficient decrease. At last, a model was developed to predict the permeability coefficient of XG-improved silty soil by using the initial dry density, XG-soil ratio, and curing age. The model can be used to rapidly predict the permeability coefficient of the improved silty soil under different conditions. This research can provide a scientific basis for the safe and scientific application of xanthan gum in seepage damage control and prevention projects. [ABSTRACT FROM AUTHOR]

Poly (ADP-ribose) Polymerase (PARP) inhibitors (PARPi) have been approved for both frontline and recurrent setting in ovarian cancer with homologous recombination (HR) repair deficiency. However, more than 40% of BRCA1/2-mutated ovarian cancer lack the initial response to PARPi treatment, and the majority of those that initially respond eventually develop resistance. Our previous study has demonstrated that increased expression of aldehyde dehydrogenase 1A1 (ALDH1A1) contributes to PARPi resistance in BRCA2-mutated ovarian cancer cells by enhancing microhomology-mediated end joining (MMEJ) but the mechanism remains unknown. Here, we find that ALDH1A1 enhances the expression of DNA polymerase θ (Polθ, encoded by the POLQ gene) in ovarian cancer cells. Furthermore, we demonstrate that the retinoic acid (RA) pathway is involved in the transcription activation of the POLQ gene. The RA receptor (RAR) can bind to the retinoic acid response element (RARE) located in the promoter of the POLQ gene, promoting transcription activation-related histone modification in the presence of RA. Given that ALDH1A1 catalyzes the biosynthesis of RA, we conclude that ALDH1A1 promotes POLQ expression via the activation of the RA signaling pathway. Finally, using a clinically-relevant patient-derived organoid (PDO) model, we find that ALDH1A1 inhibition by the pharmacological inhibitor NCT-505 in combination with the PARP inhibitor olaparib synergistically reduce the cell viability of PDOs carrying BRCA1/2 mutation and positive ALDH1A1 expression. In summary, our study elucidates a new mechanism contributing to PARPi resistance in HR-deficient ovarian cancer and shows the therapeutic potential of combining PARPi and ALDH1A1 inhibition in treating these patients. [ABSTRACT FROM AUTHOR]

Earthquake-induced slope failures are common occurrences in engineering practice. The rigid gravity retaining wall remains an effective technique in maintaining the slope stability. Based on the pseudo-dynamic approach, the seismic response of unsaturated backfills is studied using the kinematic limit analysis method. To formulate the energy balance equation, a horizontal slice method is proposed. The work rates of unsaturated soil gravity, seismic inertia force and damping force that are all characterized with conspicuous nonlinear distribution characteristics are computed using this method. A series of parametric analysis is conducted regarding the influences of soil suction and seismic excitations on the earth pressure estimations. The results show that the suction effect relates not only to the soil types but also the seismic excitations. The earth pressure is overestimated by 15%–32% when soil suction is not considered in the analyses. For hard backfills, the peak active earth pressure increases slightly and moves towards the negative direction. [ABSTRACT FROM AUTHOR]

Heterogeneous stackings of two-dimensional (2D) semiconductors and halide perovskites have attracted much attention owing to their respective superior optoelectronic properties. Black phosphorus (BP), as a unique 2D member with narrow bandgap, high mobility, and strong anisotropy, has never been combined with 2D layered perovskites. Herein, we construct a new BP-based van der Waals heterostructure combing with 2D chiral hybrid perovskite (i.e., (MBA)2PbI4) for promoting the performance and enriching the functionalities of BP. A series of BP characteristics, including carrier mobility, photoresponsivity, and polarization sensitivity, are synergistically enhanced when interfacing with (MBA)2PbI4. For instance, the photodetector responsivity and photogain of BP in heterostructures are boosted by almost one order of magnitude with respect to BP alone, which is more obvious under excitation above the bandgap of perovskite. This is because the interfacing perovskite provides an inflow of numerous photogenerated carriers to BP, to reinforce the charge carrier transfer, separation, and transport processes. Additionally, the ability of both linearly and circularly polarized photodetection can be integrated into the BP/(MBA)2PbI4 heterostructure. Our work sheds new insight on the heterostructure assembly for promising optoelectronic applications within 2D materials and perovskite families. [ABSTRACT FROM AUTHOR]

We investigate the manifestations of band structure engineering in few-layer PbI2-based heterostructures by probing their tunable optical properties. First, we have successfully prepared atomically thin flakes from PbI2 solution by two distinct approaches. A drop-casting of PbI2 solution onto various substrates followed by a simple heating process yields abundant flakes with different thickness and regular shape. Mechanical exfoliation of PbI2 bulk crystals, obtained from a low-temperature recrystallization process of PbI2 solution, also gives ultrathin PbI2 flakes of high quality. Moreover, these PbI2 flakes are employed to construct various van de Waals heterostructures. A significant enhancement of photoluminescence in MoSe2 interfaced with PbI2 was observed at different laser excitation intensity, due to the forming of type-I band alignment. Type-I band alignment can also be investigated in MoS2/PbI2 heterostructure, while type-II band alignment is built-in WSe2/PbI2 heterostructure. These results demonstrate that the strong interfacial coupling between PbI2 and other two-dimensional semiconductors can modulate their band alignment, and as a result, the exciton properties noticeably, which provides new insights of building a designer heterostructure device at the atomic level. [ABSTRACT FROM AUTHOR]

A series of wetting tests on unsaturated compacted GMZ07 sodium bentonite, taken from the Gaomiaozi area, Inner Mongolia, China, was performed to investigate the swelling characteristics of the GMZ07 sodium bentonite at temperatures of 5, 20, 60 and 75 °C. The influences of temperature and initial dry density on swelling deformation and swelling pressure were studied by performing a series of constant-stress and constant-volume tests under the wetting condition. The test results showed that the swelling deformation and swelling pressure due to saturation decreased slightly with increasing temperature. A linear relationship was present between the vertical pressure and corresponding saturated void ratio in the semi-logarithmic coordinate at a given temperature; this line is referred to as a state line. Swelling or collapse due to saturation was found to be dependent on the relative location of the initial state between the state line and initial state. The void ratios after saturation at different initial dry densities were close at the same temperature and vertical pressure. [ABSTRACT FROM AUTHOR]

Many civil engineering projects are related to hydro-mechanical behavior of unsaturated expansive soils over a wide suction range, which was investigated by imposing suctions on an expansive soil using the axis-translation technique and the vapor equilibrium technique with saturated salt solution in this paper. Water retention test results on compacted expansive soil show that void ratio keeps decreasing along with increasing the suction in an entire suction range (from 0 to about 1000 MPa), and the soil–water retention curves in terms of gravimetric water content versus suction relation are independent of the dry density or void ratio when the suction is higher than 250 kPa. Therefore, the mechanical tests on an unsaturated expansive soil with constant water content can be considered as that at constant suction when suction is higher than 250 kPa. The stress–strain behavior at different constant suctions in the entire suction range measured from triaxial shear tests under a constant net confining stress shows that the strength and stress–strain curve of specimens with higher suction are higher than those with lower suction and the higher the suction, the more dilative the specimens. The strain softening appears when the suction is higher than a specific value and the appearance of strain softening is related to the sliding surface. The tested compacted expansive soil with extremely high suctions (i.e., 38.0 and 368 MPa) shows distinct peak strength, strain-softening and dilative behavior. [ABSTRACT FROM AUTHOR]

Soil–water characteristic curves (SWCCs) play a key role in unsaturated soil mechanics. A series of SWCC tests on Yudong silt with different compaction degrees and drying–wetting cycles were conducted using a GCTS pressure plate apparatus. The test results showed that the SWCCs exhibited hysteresis during the drying–wetting cycles and were affected by the compaction degree. The hysteresis area decreased with increasing drying–wetting cycles. The hysteresis area was obviously affected by the first cycle. The second and third cycles had less obvious effects compared with the first one, but their effects could still be seen. The SWCC's parameters of Van Genuchten model were obtained by using a Lsqacurve fit function. On basis of the relationships among the fitting parameters, compaction degree, and drying–wetting cycles, a practical and novel approach was proposed to predict SWCCs for Yudong silt under different compaction degrees and drying–wetting cycles. The microstructure changes associated with variations in dry density or compaction degree have been photographed by the scanning electron microscopy (SEM). The SEM results show that the increase in dry density or compaction degree would change the macropore and surface roughness of aggregates, which will produce greater interaction among aggregates, and thus increases the air-entry value. [ABSTRACT FROM AUTHOR]

In this paper, uniaxial compression tests and digital image correlation (DIC) are combined to test samples of artificial rocks manufactured with preexisting cracks at different inclinations. The influence of these fractures on the mechanical properties of the rock and the deformation field in the rock were studied by recording and analyzing the forms of fracturing at specimen failure, crack propagation modes, crack initiation angles, and other features. The results show that the rupture modes of the specimens can be divided into two types: splitting and shear slip. The corresponding fracture types are wing fractures and secondary fractures. As the inclination angle of the prefabricated crack is increased, the wing crack propagation angle first decreases and then increases; the propagation angle is smallest when the inclination angle is 30°. The peak stress and the crack initiation stress ratios increases with the increase of the prefabricated fracture inclination angle.As a specimen is failing, the displacement in the specimen is mainly on the left side of the slip surface composed of a prefabricated crack and a wing crack and the lateral strain is mainly concentrated around the slip surface. This time interval (the time between peak stress and first appearance of a crack on the specimen's surface) and the magnitude of the peak stress display a good positive correlation. DIC technology can be used to monitor this relationship and provide early warning of deformation and failure for a rock mass in a mine or other engineering project. [ABSTRACT FROM AUTHOR]

Diamond anvil cell techniques are now well established as a powerful and wide useful method to measure the properties of materials in the very high pressure experiment. However, the measurement of material resistance at the high pressure in the experiment is a big challenge because the electrodes are difficult to be made on the diamond anvil with small top area of the 0.3 mm diameter and have good contact with the sample under the extreme high pressure conditions. In this paper, a new method is used to fabricate the microelectrodes on the diamond anvil surface for the high pressure experiment. Firstly, a special Nickel shadow mask with the electrode patterns, which is made by micro-fabrication technology, is installed and fixed onto the diamond anvil surface with the glue by aligning the electrodes of the shadow mask with the center of the diamond anvil under the microscope. Then, the metal film is deposited onto the anvil with nickel shadow mask by magnetron sputtering. Finally, the microelectrodes having the same patterns with the hollowed structures of the shadow mask can be made with the sputtering material to adhere on the diamond anvil surface after the removal of the shadow mask off the anvil. This new method is simpler, easier to be operated, and less pollution produced to the diamond anvil cell than the traditional method. [ABSTRACT FROM AUTHOR]

Topological nodal-line semimetal is a new emerging material, which is viewed as a three-dimensional (3D) analog of graphene with the conduction and valence bands crossing at Dirac nodes, resulting in a range of exotic transport properties. Herein, we report on the direct quantum transport evidence of the 3D topological nodal-line semimetal phase of ZrSiS with angular-dependent magnetoresistance (MR) and the combined de Hass-van Alphen (dHvA) and Shubnikov-de Hass (SdH) oscillations. Through fitting by a two-band model, the MR results demonstrate high topological nodal-line fermion densities of approximately 6 × 10 cm and a perfect electron/hole compensation ratio of 0.94, which is consistent with the semi-classical expression fitting of Hall conductance G and the theoretical calculation. Both the SdH and dHvA oscillations provide clear evidence of 3D topological nodal-line semimetal characteristic. [ABSTRACT FROM AUTHOR]

Background: Most migraineurs develop cutaneous allodynia (CA) during migraine, and the underlying mechanism of CA in migraine is thought to be sensitization of the third-order trigeminovascular neurons in the posterior thalamic nuclei. This study aimed to investigate whether the ascending/descending pathway associated with the thalamus is disturbed in migraineurs with CA (MWCA) using effective connectivity analysis of resting-state functional magnetic resonance imaging. Methods: Thirty four migraineurs without aura (14 MWCA and 20 migraineurs without CA (MWoCA)) and 25 matched healthy controls (HC) were recruited in the study. The effective connectivity pathways associated with the posterior thalamus (PTH) were investigated using the Granger causality analysis. We chose bilateral PTH as two individual seeds, and compared MWCA with MWoCA and HC, respectively. Spearman correlation analysis was performed to test the correlation between the abnormal effective connectivity and the allodynia severity of MWCA. Results: Compared with MWoCA, MWCA showed decreased inflows from the left limbic regions and dorsal medial prefrontal cortex (dmPFC) to the ipsilateral PTH, as well as increased inflow from the right ventral medial prefrontal cortex (vmPFC) to the ipsilateral PTH; no significantly different outflows from the bilateral PTH to other regions were found. Compared with HC, MWCA showed increased outflows from the left PTH to the bilateral vmPFC, decreased outflows from the right PTH to the bilateral temporoparietal areas, decreased inflow from the left parietooccipital area to the ipsilateral PTH, and increased inflows from the right dorsolateral prefrontal cortex and the bilateral temporoparietal areas to the right PTH. Correlation analyses revealed that the disturbed connectivities between PTH and cuneus, as well as PTH and middle frontal gyrus were associated with the allodynia severity of MWCA. Conclusions: MWCA demonstrated disrupted effective connection pathways between the PTH and other cortical or subcortical regions that participated in multi-dimentional pain processing. Our findings highlight the dysfunctional ascending and descending pain network at the thalamic-level and may help to illuminate the possible pathophysiologic mechanisms of CA. [ABSTRACT FROM AUTHOR]

Tension-type headache (TTH) is the most prevalent type of primary headache. Many studies have shown that the pathogenesis of primary headache is associated with fine structural or functional changes. However, these studies were mainly based on migraine. The present study aimed to investigate whether TTH patients show functional disturbances compared with healthy subjects. We used restingstate functional magnetic resonance imaging (fMRI) and regional homogeneity (ReHo) analysis to identify changes in the local synchronization of spontaneous activity in patients with TTH. Ten patients with TTH and 10 age-, gender-, and education-matched healthy controls participated in the study. After demographic and clinical characteristics were acquired, a 3.0-T MRI system was used to obtain resting-state fMRIs. Compared with healthy controls, the TTH group exhibited significantly lower ReHo values in the bilateral caudate nucleus, the precuneus, the putamen, the left middle frontal gyrus, and the superior frontal gyrus. There was no correlation between mean ReHo values in TTH patients and duration of TTH, number of attacks, duration of daily attacks, Visual Analogue Scale score, or Headache Impact Test-6 score. These results suggest that TTH patients exhibit reduced synchronization of neuronal activity in multiple regions involved in the integration and processing of pain signals. [ABSTRACT FROM AUTHOR]

DNA double-strand breaks (DSBs) are generated by the recombination activating gene (RAG) endonuclease in all developing lymphocytes as they assemble antigen receptor genes. DNA cleavage by RAG occurs only at the G1 phase of the cell cycle and generates two hairpin-sealed DNA (coding) ends that require nucleolytic opening before their repair by classical non-homologous end-joining (NHEJ). Although there are several cellular nucleases that could perform this function, only the Artemis nuclease is able to do so efficiently. Here, in vivo, we show that in murine cells the histone protein H2AX prevents nucleases other than Artemis from processing hairpin-sealed coding ends; in the absence of H2AX, CtIP can efficiently promote the hairpin opening and resection of DNA ends generated by RAG cleavage. This CtIP-mediated resection is inhibited by γ-H2AX and by MDC-1 (mediator of DNA damage checkpoint 1), which binds to γ-H2AX in chromatin flanking DNA DSBs. Moreover, the ataxia telangiectasia mutated (ATM) kinase activates antagonistic pathways that modulate this resection. CtIP DNA end resection activity is normally limited to cells at post-replicative stages of the cell cycle, in which it is essential for homology-mediated repair. In G1-phase lymphocytes, DNA ends that are processed by CtIP are not efficiently joined by classical NHEJ and the joints that do form frequently use micro-homologies and show significant chromosomal deletions. Thus, H2AX preserves the structural integrity of broken DNA ends in G1-phase lymphocytes, thereby preventing these DNA ends from accessing repair pathways that promote genomic instability. [ABSTRACT FROM AUTHOR]

Mediator of DNA damage checkpoint protein-1 (MDC1) is a recently identified nuclear protein that participates in DNA-damage sensing and signaling. Here we report that knockdown of MDC1 by RNA interference results in cellular hypersensitivity to the DNA cross-linking agent mitomycin C and ionizing radiation and in impaired homology-mediated repair of double-strand breaks in DNA. MDC1 forms a complex with Rad51 through a direct interaction with the forkhead-associated domain of MDC1, not the BRCA1 C-terminal domain. Depletion of MDC1 results in impaired formation of Rad51 ionizing radiation–induced foci, reduced amounts of nuclear and chromatin-bound Rad51, and a corresponding increase in Rad51 protein degradation. Together, our findings suggest that MDC1 functions in Rad51-mediated homologous recombination by retaining Rad51 in chromatin. [ABSTRACT FROM AUTHOR]

Crystallization-induced photoluminescence weakening was recently revealed in ultrasmall metal nanoparticles. However, the fundamentals of the phenomenon are not understood yet. By obtaining conformational isomer crystals of gold nanoclusters, we investigate crystallization-induced photoluminescence weakening and reveal that the shortening of interparticle distance decreases photoluminescence, which is further supported by high-pressure photoluminescence experiments. To interpret this, we propose a distance-dependent non-radiative transfer model of excitation electrons and support it with additional theoretical and experimental results. This model can also explain both aggregation-induced quenching and aggregation-induced emission phenomena. This work improves our understanding of aggregated-state photoluminescence, contributes to the concept of conformational isomerism in nanoclusters, and demonstrates the utility of high pressure studies in nanochemistry. Crystallization-induced photoluminescence weakening in ultrasmall metal nanoparticles is not well understood. Here, the authors study conformational isomers of gold nanoclusters to examine the effect of interparticle distance on this phenomenon, and propose a model of distance-dependent non-radiative excitation electron transfer. [ABSTRACT FROM AUTHOR]

Background: Major depressive disorder is a common comorbidity in migraineurs. Depression may affect the progression and prognosis of migraine. Few studies have examined the brain function in migraineurs that may cause this comorbidity. Here, we aimed to explore depression-related abnormalities in the intrinsic brain activity of interictal migraineurs with comorbid depression using resting-state functional magnetic resonance imaging.Results: Significant main effects of migraine and depression provided evidence that migraine and depression jointly affected the left medial prefrontal cortex, which was thought to be the neural basis of self-referential mental activity in previous studies. Abnormalities in this region may contribute to determining the common symptoms of migraine and depression and even result in comorbidity. Additionally, migraineurs with comorbid depression had different developmental trajectories in the right thalamus and fusiform, which were associated with recognizing, transmitting, controlling and remembering pain and emotion.Conclusions: Based on our findings, the abnormal mPFC which may contribute to determining the common symptoms in migraine and depression and may be a therapeutic target for migraineurs comorbid depression. The different developmental trajectory in thalamus and fusiform indicates that the comorbidity may arise through a specific mechanism rather than simple superposition of migraine and depression. [ABSTRACT FROM AUTHOR]