Green Light from Red-Emitting Nanocrystals: Broadband, Low-Threshold Lasing from Colloidal Quantum Shells in Optical Nanocavities.

Spherical semiconductor nanoplatelets, known as quantum shells (QSs), have captured significant interest for their strong suppression of Auger recombination, which leads to long multiexciton lifetimes and wide optical gain bandwidth. Yet, the realization of benefits associated with the multiexciton lasing regime using a suitably designed photonic cavity remains elusive. Here, we demonstrate broadly tunable lasing from close-packed films of CdS/CdSe/CdS QSs deposited over nanopillar arrays on Si substrates. Wide spectral tuning of the stimulated emission in QSs with a fixed bandgap value was achieved by engaging single exciton (λX ∼ 634 nm), biexciton (λBX ∼ 627 nm), and multiple exciton (λMX ∼ 615-565 nm) transitions. The ensemble-averaged gain threshold of ∼ 2.6 electron-hole pairs per QS particle and the low photonic cavity fluence threshold of ∼4 µJ/cm2 were attributed to Auger suppression. The tuning of the lasing emission closely aligns with our model predictions achieved by varying the array period while preserving mode confinement and quality (Q) factors. These results mark a notable step toward the development of colloidal nanocrystal lasers.

Quantum Shells Boost the Optical Gain of Lasing Media.

Auger decay of multiple excitons represents a significant obstacle to photonic applications of semiconductor quantum dots (QDs). This nonradiative process is particularly detrimental to the performance of QD-based electroluminescent and lasing devices. Here, we demonstrate that semiconductor quantum shells with an "inverted" QD geometry inhibit Auger recombination, allowing substantial improvements to their multiexciton characteristics. By promoting a spatial separation between multiple excitons, the quantum shell geometry leads to ultralong biexciton lifetimes (>10 ns) and a large biexciton quantum yield. Furthermore, the architecture of quantum shells induces an exciton-exciton repulsion, which splits exciton and biexciton optical transitions, giving rise to an Auger-inactive single-exciton gain mode. In this regime, quantum shells exhibit the longest optical gain lifetime reported for colloidal QDs to date (>6 ns), which makes this geometry an attractive candidate for the development of optically and electrically pumped gain media.

SHA-MTL: soft and hard attention multi-task learning for automated breast cancer ultrasound image segmentation and classification.

Purpose The automatic analysis of ultrasound images facilitates the diagnosis of breast cancer effectively and objectively. However, due to the characteristics of ultrasound images, it is still a challenging task to achieve analyzation automatically. We suppose that the algorithm will extract lesion regions and distinguish categories easily if it is guided to focus on the lesion regions.Method We propose a multi-task learning (SHA-MTL) model based on soft and hard attention mechanisms for breast ultrasound (BUS) image simultaneous segmentation and binary classification. The SHA-MTL model consists of a dense CNN encoder and an upsampling decoder, which are connected by attention-gated (AG) units with soft attention mechanism. Cross-validation experiments are performed on BUS datasets with category and mask labels, and multiple comprehensive analyses are performed on the two tasks.Results We assess the SHA-MTL model on a public BUS image dataset. For the segmentation task, the sensitivity and DICE of the SHA-MTL model to the lesion regions increased by 2.27% and 1.19% compared with the single task model, respectively. The classification accuracy and F1 score increased by 2.45% and 3.82%, respectively.Conclusion The results validate the effectiveness of our model and indicate that the SHA-MTL model requires less a priori knowledge to achieve better results by comparing with other recent models. Therefore, we can draw the conclusion that paying more attention to the lesion region of BUS is conducive to the discrimination of lesion types.

Tibetan Medicine Duoxuekang Capsule Ameliorates High-Altitude Polycythemia Accompanied by Brain Injury.

Objective: Duoxuekang (DXK) capsule is an empirical prescription for Tibetan medicine in the treatment of hypobaric hypoxia (HH)-induced brain injury in the plateau. This study aimed to investigate the protective effects and underlying molecular mechanisms of DXK on HH-induced brain injury. Methods: UPLC-Q-TOF/MS was performed for chemical composition analysis of DXK. The anti-hypoxia and anti-fatigue effects of DXK were evaluated by the normobaric hypoxia test, sodium nitrite toxicosis test, and weight-loaded swimming test in mice. Simultaneously, SD rats were used for the chronic hypobaric hypoxia (CHH) test. RBC, HGB, HCT, and the whole blood viscosity were evaluated. The activities of SOD and MDA in the brain, and EPO and LDH levels in the kidney were detected using ELISA. H&E staining was employed to observe the pathological morphology in the hippocampus and cortex of rats. Furthermore, immunofluorescence and Western blot were carried out to detect the protein expressions of Mapk10, RASGRF1, RASA3, Ras, and IGF-IR in the brain of rats. Besides, BALB/c mice were used for acute hypobaric hypoxia (AHH) test, and Western blot was employed to detect the protein expression of p-ERK/ERK, p-JNK/JNK, and p-p38/p38 in the cerebral cortex of mice. Results: 23 different chemical compositions of DXK were identified by UPLC-Q-TOF/MS. The anti-hypoxia test verified that DXK can prolong the survival time of mice. The anti-fatigue test confirmed that DXK can prolong the swimming time of mice, decrease the level of LDH, and increase the hepatic glycogen level. Synchronously, DXK can decrease the levels of RBC, HGB, HCT, and the whole blood viscosity under the CHH condition. Besides, DXK can ameliorate CHH-induced brain injury, decrease the levels of EPO and LDH in the kidney, reduce MDA, and increase SOD in the hippocampus. Furthermore, DXK can converse HH-induced marked increase of Mapk10, RASGRF1, and RASA3, and decrease of Ras and IGF-IR. In addition, DXK can suppress the ratio of p-ERK/ERK, p-JNK/JNK, and p-p38/p38 under the HH condition. Conclusion: Together, the cerebral protection elicited by DXK was due to the decrease of hematological index, suppressing EPO, by affecting the MAPK signaling pathway in oxidative damage, and regulating the RAS signaling pathway.

Computational and functional characterization of four SNPs in the SOST locus associated with osteoporosis.

The SOST gene encodes sclerostin, a C-terminal cysteine knot-like domain containing key negative regulator of osteoblastic bone formation that inhibits LRP5/6-mediated canonical Wnt signaling. Numerous single nucleotide polymorphisms (SNPs) in the SOST locus are firmly associated with bone mineral density (BMD) and fracture in genome-wide association studies (GWAS) and candidate gene association studies. However, the validation and mechanistic elucidation of causal genetic variants, especially for SNPs located beyond the promoter-proximal region, remain largely unresolved. By employing computational and experimental approaches, here we identify four SNPs rs1230399, rs7220711, rs1107748 and rs75901553 as functional variants which display allelic variation in SOST gene expression. The osteoporosis associated SNP rs1230399 in the SOST distal upstream regulatory region shows FOXA1 binding activity with subsequent transinactivation in a T allele-specific manner. The BMD GWAS lead SNPs rs7220711 and rs1107748 both reside in the 52-kb regulatory element deletion 35-kb downstream of the SOST gene which leads to Van Buchem disease. The rs7220711-A has a higher affinity for the transcriptional repressors MAFF or MAFK homodimers than rs7220711-G, while rs1107748 confers C allele specific transcriptional enhancer activity via a CTCF binding element. The variant rs75901553 C>T located in a conserved site of the SOST 3' UTR abolishes a target binding site for miR-98-5p which is negatively responsive to parathyroid hormone or 17ß-estradiol in osteoblastic cell lines. Our findings uncover the biological consequences of four independent genetic variants in the SOST region and their important roles in SOST expression via diverse mechanisms, providing new insights into the genetics and molecular pathogenesis of osteoporosis.

Systems Study on the Antirheumatic Mechanism of Tibetan Medicated-Bath Therapy Using Wuwei-Ganlu-Yaoyu-Keli.

In clinical practice at Tibetan area of China, Traditional Tibetan Medicine formula Wuwei-Ganlu-Yaoyu-Keli (WGYK) is commonly added in warm water of bath therapy to treat rheumatoid arthritis (RA). However, its mechanism of action is not well interpreted yet. In this paper, we first verify WGYK's anti-RA effect by an animal experiment. Then, based on gene expression data from microarray experiments, we apply approaches of network pharmacology to further reveal the mechanism of action for WGYK to treat RA by analyzing protein-protein interactions and pathways. This study may facilitate our understanding of anti-RA effect of WGYK from perspective of network pharmacology.

[Simultaneous determination of ten major compounds including iridoid glycosides and phenolic acids in Pterocephalus hookeri by UPLC-PDA].

This study is to develop an UPLC-PDA method for determination of 10 major components in Pterocephalus. The UPLC-PDA assay was performed on a Waters Acquity UPLCR BEH C18（2.1 mm ×100 mm,1.7 µm）, and the column temperature was at 30 ℃. The mobile phase consists of water containing 0.2% phosphoric acid (A) and acetonitrile (B) in gradient elution at a flow rate of 0.4 mL•min⁻¹. The detection wave length was set at 237 and 325 nm, and the injection volume was 1 µL in the UPLC system. The linear range of 10 detected compounds were good (r≥0.999 7), and the overall recoveries ranged from 96.30% to 103.0%, with the RSD ranging from 0.72% to 2.9%. The method was simple, accurate and reproducible, which can be used for the simultaneous determination of the content of ten major components in P. hookeri.

[Action mechanism of total flavonoids of Hippophae rhamnoides in treatment of myocardial ischemia based on network pharmacology].

In this study, a network pharmacological screening method was adopted to further study the active ingredients and action mechanism of total flavonoids of Hippophae rhamnoides(TFH) for the treatment of myocardial ischemia. Firstly TCMSP database and PubChem database were searched, and then the data were combined with oral bioavailability and drug analysis to screen flavonoids of H.rhamnoides compounds. Then predictive analysis was conducted for the 7 screened compounds by ChemMapper server.The obtained potential targets were imported into MAS 3.0. Database, and KEGG database was also used for targets analysis and pathway analysis. Finally Cystoscope 3.3.0 software was used to draw "compounds-targets-pathway" network diagram. Virtual experiments predicted 68 potential targets and 60 signaling pathways, and 31 targets and 23 pathways of them were directly or indirectly associated with myocardial ischemia. The results showed that TFH played a synergistic rolemainly through the regulation of calcium signaling pathway, VEGF signaling pathway and gap junction signaling pathway, which was consistent with literature reports. These results indicated that it can enhance heart function, protect vascular endothelial cells, and fight against myocardial ischemia probably by regulating platelet aggregation, lipid metabolism, inflammation and other processes.

Hydrolysis of polyaluminum chloride prior to coagulation: Effects on coagulation behavior and implications for improving coagulation performance.

The effects of polyaluminum chloride (PACl) hydrolysis prior to coagulation on both the coagulation zone and coagulation performance of a kaolin suspension were investigated by a novel jar test named the "reversed coagulation test". The tests showed that PACl hydrolysis prior to coagulation decreased the performance of charge neutralization coagulation in the case of short-time slow mixing (10min; G=15sec-1) and increased the optimal dosage for charge neutralization and sweep coagulation. Moreover, the hydrolysis time had insignificant effects on the size and zeta potential of PACl precipitates and the residual turbidity of the raw water. However, PACl hydrolysis prior to coagulation and the size of PACl precipitates had a negligible effect on the performance of sweep coagulation. The results imply that, in practice, preparing a PACl solution with deionized water, rather than tap water or the outlet water from a wastewater treatment unit, can significantly save PACl consumption and improve the performance of charge neutralization coagulation, while preparing the PACl solution with tap or outlet water would not affect the performance of sweep coagulation. In addition, the optimal rapid mixing intensity appears to be determined by a balance between the degree of coagulant hydrolysis before contacting the primary particles and the average size of flocs in the rapid mixing period. These results provide new insights into the role of PACl hydrolysis and will be useful for improving coagulation efficiency.