In this study, we utilized a dielectric Bragg reflector (DBR) as a mirror and positioned a wide-spectrum FAMACsPb(BrI)3 halide perovskite film between two DBRs to construct a vertical-cavity ...surface-emitting laser (VCSEL) structure. The top and bottom DBRs were connected using optical adhesive, allowing us to control the cavity length by applying external force. Through this approach, we achieved operation at the desired wavelength. Due to the exceptional optical gain provided by FAMACsPb(BrI)3, we successfully observed multimode and lasing phenomena at room temperature under continuous-wave (CW) laser excitation. The outcomes of this study provide valuable insights for the application of novel VCSEL structures and highlight the potential of using FAMACsPb(BrI)3 halide perovskites in optical gain. This work holds significant implications for the fields of optical communication and laser technology.
CH3NH3PbI3 perovskite material has demonstrated great promise in high-performance solar cells and light-emitting devices (LEDs). In this work, we investigated the impact of the coexistence of PbI2 ...and CH3NH3PbI3 perovskite on photoluminescence (PL) properties. In absorbance and PL measurements performed at room temperature, we observed an emission peak at 780 nm, which is consistent with the band-edge absorption of CH3NH3PbI3. On the top surface, we observed dissolved PbI2, which could serve as a passivation species for improving PL stability upon exposure to ambient conditions. Specifically, dual-peak PL spectra were observed at room temperature. The peak at 780 nm originates from the free-carrier transition of CH3NH3PbI3 and the peak at 796 nm originates from the PbI2-related recombination. Based on time-resolved PL and X-ray diffraction measurements, we can conclude that unconverted and dissolved PbI2 in CH3NH3PbI3 forms a type-II band alignment at the CH3NH3PbI3/PbI2 interface. This type II hetero-structure indeed influences the quality and PL performance of perovskites. To check this structure or quality of perovskite, x-ray diffraction (XRD) and x-ray photoemission spectroscopy (XPS) are common ways. Here, we demonstrated a cheaper, faster and more convenience method, PL measurement, to check the quality of CH3NH3PbI3 perovskite films. It should be a useful way to check the quality perovskite-based LEDs and solar cells merely by observing whether the dual peaks exist or not in the PL spectra.
Dysregulation of RNA splicing processes is intricately linked to tumorigenesis in various cancers, especially breast cancer. Cdc2‐like kinase 2 (CLK2), an oncogenic RNA‐splicing kinase pivotal in ...breast cancer, plays a significant role, particularly in the context of triple‐negative breast cancer (TNBC), a subtype marked by substantial medical challenges due to its low survival rates. In this study, we employed a structure‐based virtual screening (SBVS) method to identify potential CLK2 inhibitors with novel chemical structures for treating TNBC. Compound 670551 emerged as a novel CLK2 inhibitor with a 50% inhibitory concentration (IC50) value of 619.7 nM. Importantly, Compound 670551 exhibited high selectivity for CLK2 over other protein kinases. Functionally, this compound significantly reduced the survival and proliferation of TNBC cells. Results from a cell‐based assay demonstrated that this inhibitor led to a decrease in RNA splicing proteins, such as SRSF4 and SRSF6, resulting in cell apoptosis. In summary, we identified a novel CLK2 inhibitor as a promising potential treatment for TNBC therapy.
Chemical exchange saturation transfer (CEST) imaging benefits from a longer saturation duration and a higher saturation duty cycle. Dielectric shading effects occur when the radiofrequency (RF) ...wavelength approaches the object size. Here, we proposed a simultaneous parallel transmission‐based CEST (pTx‐CEST) sequence to prolongate the saturation duration at a 100% duty cycle and improve the RF saturation homogeneity in CEST imaging. The simultaneous pTx‐CEST sequence was implemented by switching the CEST saturation module from the non‐pTx to pTx mode, using the pTx functionality with both transmit channels being driven simultaneously (instead of time‐interleaved). The optimization of amplitude ratio and phase difference settings between RF channels for best B1 homogeneity was performed in phantoms of two different sizes mimicking the human brain and abdomen. The optimal amplitude and phase settings generating the best B1 homogeneity in the phantoms were used in pTx‐CEST scans of the human study. The comparison of the maximum achievable saturation duration between the non‐pTx‐CEST and pTx‐CEST sequences was performed in a protein phantom, healthy volunteers, and a metastatic brain tumor patient. The optimal amplitude ratio and phase difference setting between transmit channels manifested circular and elliptical polarization in the head‐sized and abdomen‐sized phantoms. In the brain, the maximum saturation durations achieved at a 100% duty cycle using the simultaneous pTx‐CEST sequence were prolonged to 2240, 3220, and 4200 ms compared with 980 ms using the non‐pTx‐CEST sequence at repetition times of 3, 4, and 5 s, respectively. The longer saturation duration helped improve the image contrast between the tumor and the normal tissue in the patient. The optimized elliptical polarization mode saturation pulses yielded improved uniformity of CEST signals acquired from the human abdomen. The proposed simultaneous pTx‐CEST sequence enabled essentially arbitrarily long saturation duration at a 100% duty cycle and helped reduce the dielectric shading effects with the optimized RF setting.
A parallel transmission‐based CEST (pTx‐CEST) sequence to extend the maximum saturation duration at 100% duty cycle and mitigate shading effects in CEST imaging. The longer saturation duration provided by the pTx‐CEST sequence helped to improve the tumor‐normal contrast in the patient. The optimized elliptical polarization mode saturation pulses improved the uniformity of CEST signals acquired from the human abdomen.
Vitamin D deficiency has been epidemiologically linked to Alzheimer's disease (AD) and other dementias, but no interventional studies have proved causality. Our previous work revealed that the ...genomic vitamin D receptor (VDR) is already converted into a non‐genomic signaling pathway by forming a complex with p53 in the AD brain. Here, we extend our previous work to assess whether it is beneficial to supplement AD mice and humans with vitamin D. Intriguingly, we first observed that APP/PS1 mice fed a vitamin D‐sufficient diet showed significantly lower levels of serum vitamin D, suggesting its deficiency may be a consequence not a cause of AD. Moreover, supplementation of vitamin D led to increased Aβ deposition and exacerbated AD. Mechanistically, vitamin D supplementation did not rescue the genomic VDR/RXR complex but instead enhanced the non‐genomic VDR/p53 complex in AD brains. Consistently, our population‐based longitudinal study also showed that dementia‐free older adults (n = 14,648) taking vitamin D3 supplements for over 146 days/year were 1.8 times more likely to develop dementia than those not taking the supplements. Among those with pre‐existing dementia (n = 980), those taking vitamin D3 supplements for over 146 days/year had 2.17 times the risk of mortality than those not taking the supplements. Collectively, these animal model and human cohort studies caution against prolonged use of vitamin D by AD patients.
We studied whether it is beneficial to supplement vitamin D to APP/PS1 mice and humans. The animal studies show vitamin D deficiency is an early disease outcome and supplementation of vitamin D worsens AD brain pathology via enhancing VDR/p53 complex to impair autophagosome. Nationwide longitudinal cohort studies also suggest long‐term vitamin D supplementation is associated with higher risk of dementia in dementia‐free older adults and higher mortality in dementia individuals. Our results caution against prolonged use of vitamin D by AD patients and older adults.
Nontoxic metal-halide perovskite materials have triggered a revolution of emitting devices as well as solar cells. In this work, we demonstrate a lead-free γ-CsSnI3 perovskite random lasing operated ...at room temperature in ambient air. The high-purity γ-CsSnI3 films with the orthorhombic structure were grown by chemical vapor deposition (CVD). From the absorption and photoluminescence (PL) spectra, the intense PL emission at 950 nm is consistent with the γ-CsSnI3 band-edge absorption. Moreover, the PL stability test shows the prolonged stability of CVD-grown films. With increasing excitation energy above 18 mJ/cm2, the random laser with a high Q-factor (∼3000) is achieved.
Non-invasive measurement of cerebral venous oxygenation (Y
) is of critical importance in brain diseases. The present work proposed a fast method to quantify regional Y
map for both large and small ...veins.
A new sequence was developed, referred to as TRU-VERA (T
relaxation under velocity encoding and rapid acquisition, which isolates blood spins from static tissue with velocity-encoding preparation, modulates the T
weighting of venous signal with T
-preparation and utilizes a bSSFP readout to achieve fast acquisition with high resolution. The sequence was first optimized to achieve best sensitivity for both large and small veins, and then validated with TRUST (T
relaxation under spin tagging), TRUPC (T
relaxation under phase contrast), and accelerated TRUPC MRI. Regional difference of Y
was evaluated, and test-retest reproducibility was examined.
Optimal Venc was determined to be 3 cm/s, while recovery time and balanced SSFP flip angle within reasonable range had minimal effect on SNR efficiency. Venous T
measured with TRU-VERA was highly correlated with T
from TRUST (R
= 0.90), and a conversion equation was established for further calibration to Y
. TRU-VERA sequences showed consistent Y
estimation with TRUPC (R
= 0.64) and accelerated TRUPC (R
= 0.79). Coefficient of variation was 0.84% for large veins and 2.49% for small veins, suggesting an excellent test-retest reproducibility.
The proposed TRU-VERA sequence is a promising method for vessel-specific oxygenation assessment.
Ambient ionization mass spectrometry (AIMS) has grown into a group of emerging analytical techniques that allow rapid, real-time, high-throughput, in situ, and in vivo analysis in many scientific ...fields including biomedicine, pharmaceuticals, and forensic sciences. While dozens of AIMS techniques have been introduced over the past two decades, their broad commercial and industrial use is still restricted by multiple challenges. In this Perspective, we discuss the most relevant technical challenges facing AIMS, i.e., reproducibility, quantitative ability, molecular coverage, sensitivity, and data complexity, and scientists’ recent attempts to overcome these hurdles. Furthermore, we present future directions of AIMS from our perspective, including the necessity that efforts should be made to unravel blind biomolecules in routine analysis, the construction of a data depository for AIMS users, the full automation of pipelines for prospect integration in a robotic laboratory, the movement toward on-site tests, and the expansion of outreach to motivate government officials in policymaking. We anticipate that, with progress in these critical but immature areas, AIMS technology will keep evolving to become a more robust and user-friendly set of technologies and, consequently, be translated into everyday life practice.
In this work, we propose a system to track the clouds and predict relevant events based on all-sky images. To deal with the nature of variable appearance of clouds, we use clusters of feature points ...to perform tracking. We propose an enhanced clustering algorithm that does not require prior knowledge of number of clusters. The proposed clustering algorithm can successfully separate feature points into groups with reasonable sizes and ranges. In the tracking process, merging and splitting of clouds are handled via checking matched pairs of feature points among different clusters. Afterwards, the tracking information is utilized to predict if the sun will be covered or obscured by clouds within the prediction horizon. Features are extracted from the tracked feature points and a Markov chain model is designed to perform ramp-down event prediction. The obscuration and ramp-down events have an important impact on solar irradiance. The experiments have shown that the proposed system can substantially enhance the accuracy of solar irradiance nowcasting on a challenging dataset.
•Cloud tracking is achieved using clusters of feature points.•An enhanced clustering algorithm is proposed to prevent over-clustering or under-clustering.•Obscuration events are predicted with features of clustering and tracking information.•A graph based model is designed to prediction ramp-down events.•Detection results are applied in irradiance nowcasting frameworks to improve accuracy.
Abstract
Mass spectrometry imaging (MSI) is a powerful technique that reveals the spatial distribution of various molecules in biological samples, and it is widely used in pathology‐related research. ...In this review, we summarize common MSI techniques, including matrix‐assisted laser desorption/ionization and desorption electrospray ionization MSI, and their applications in pathological research, including disease diagnosis, microbiology, and drug discovery. We also describe the improvements of MSI, focusing on the accumulation of imaging data sets, expansion of chemical coverage, and identification of biological significant molecules, that have prompted the evolution of MSI to meet the requirements of pathology practices. Overall, this review details the applications and improvements of MSI techniques, demonstrating the potential of integrating MSI techniques into next‐generation pathology practices.
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