Lead sulphide (PbS) nanocrystals (NCs) are promising materials for low-cost, high-performance optoelectronic devices. So far, PbS NCs have to be first synthesized with long-alkyl chain organic surface ligands and then be ligand-exchanged with shorter ligands (two-steps) to enable charge transport. However, the initial synthesis of insulated PbS NCs show no necessity and the ligand-exchange process is tedious and extravagant. Herein, we have developed a direct one-step, scalable synthetic method for iodide capped PbS (PbS-I) NC inks. The estimated cost for PbS-I NC inks is decreased to less than 6 $·g−1, compared with 16 $·g−1 for conventional methods. Furthermore, based on these PbS-I NCs, photodetector devices show a high detectivity of 1.4 × 1011 Jones and solar cells show an air-stable power conversion efficiency (PCE) up to 10%. This scalable and low-cost direct preparation of high-quality PbS-I NC inks may pave a path for the future commercialization of NC based optoelectronics.

Current efforts on lead sulfide quantum dot (PbS QD) solar cells are mostly paid to the device architecture engineering and postsynthetic surface modification, while very rare work regarding the optimization of PbS synthesis is reported. Here, PbS QDs are successfully synthesized using PbO and PbAc · 3H O as the lead sources. QD solar cells based on PbAc-PbS have demonstrated a high power conversion efficiency (PCE) of 10.82% (and independently certificated values of 10.62%), which is significantly higher than the PCE of 9.39% for PbO-PbS QD based ones. For the first time, systematic investigations are carried out on the effect of lead precursor engineering on the device performance. It is revealed that acetate can act as an efficient capping ligands together with oleic acid, providing better surface coverage and replace some of the harmful hydroxyl (OH) ligands during the synthesis. Then the acetate on the surface can be exchanged by iodide and lead to desired passivation. This work demonstrates that the precursor engineering has great potential in performance improvement. It is also pointed out that the initial synthesis is an often neglected but critical stage and has abundant room for optimization to further improve the quality of the resultant QDs, leading to breakthrough efficiency.

In this work, we demonstrate high-efficiency planar perovskite solar cells (PSCs), using room-temperature sputtered niobium oxide (NbO) as the electron-transporting layer (ETL). Widely spread ETL-like TiO often requires high-temperature (>450 °C) sintering, which is not desired for the fabrication of flexible devices. The amorphous NbO (labeled as a-NbO) ETL, without any heat treatment, can give a best power conversion efficiency (PCE) of 17.1% for planar PSCs. Interestingly, the crystalline NbO (labeled as c-NbO), with high-temperature (500 °C) annealing, results in a very similar PCE of 17.2%, indicating the great advantage of a-NbO in energy saving. We thus carried out a systematical investigation on the properties of the a-NbO film. The Hall effect measurements indicate both high mobility and conductivity of the a-NbO film. Kelvin probe force microscopy measurements define the Fermi levels of a-NbO and c-NbO as -4.31 and -4.02 eV, respectively, which allow efficient electron extraction at the NbO/perovskite interface, regardless of the additional heat treatment on NbO film. Benefitting from the low-temperature process, we further demonstrated flexible PSCs based on a-NbO, with a considerable PCE of 12.1%. The room-temperature processing and relatively high device performance of a-NbO suggest a great potential for its application in optoelectrical devices.

Na؉ /K ؉ -ATPase, a plasma membrane protein abundantly expressed in epithelial tissues, has been identified and linked to numerous biological events, including ion transport and reabsorption. In Na ؉ /K ؉ -ATPase, the ␤-subunit plays a fundamental role in the structural integrity and functional maturation of holoenzyme. Estrogens are important circulating hormones that can regulate Na ؉ /K ؉ -ATPase abundance and activity; however, the specific molecules participating in this process are largely unknown. Here, we characterize that N-myc downstream-regulated gene 2 (NDRG2) is an estrogen up-regulated gene. 17␤-Estradiol binds with estrogen receptor ␤ but not estrogen receptor ␣ to up-regulate NDRG2 expression via transcriptional activation. We also find that NDRG2 interacts with the ␤1-subunit of Na ؉ /K ؉ -ATPase and stabilizes the ␤1-subunit by inhibiting its ubiquitination and degradation. NDRG2-induced prolongation of the ␤1-subunit protein half-life is accompanied by a similar increase in Na ؉ /K ؉ -ATPase-mediated Na ؉ transport and Na ؉ current in epithelial cells. In addition, NDRG2 silencing largely attenuates the accumulation of ␤1-subunit regulated by 17␤-estradiol. Our results demonstrate that estrogen/NDRG2/Na ؉ /K ؉ -ATPase ␤1 pathway is important in promoting Na ؉ /K ؉ -ATPase activity and suggest this novel pathway might have substantial roles in ion transport, fluid balance, and homeostasis. Na ϩ /K ϩ -ATPase, a plasma membrane ion pump, has numerous physiological functions. Of note, it is consisted of three subunits (1), ␣, ␤, and ␥, and the holoenzyme activity required by the participation of the three subunits. ␣ is the catalytic subunit of the enzyme that utilizes ATP hydrolysis to pump K ϩ into the cell in exchange for Na ϩ , which is essential for maintaining normal resting membrane potentials and facilitating the exchange of other materials needed for cellular homeostasis and activity (2-4). ␤-Subunit is responsible for the formation and integrity of the holoenzyme. In vertebrate cells, ␤-subunit may stabilize the correct folding of the ␣-subunit to facilitate its delivery to the plasma membrane (5-7). In addition, evidence showed that ␤-subunit is related to the cell motility and invasion (8, 9). At present, four ␣-isoforms known as ␣1, ␣2, ␣3, ␣4 as well as three different ␤-polypeptides termed as ␤1, ␤2, and ␤3 (3) have been identified. Among these isoforms, ␣1␤1 distributes in nearly every tissue whereas other isoforms exhibit a tissue-specific pattern of expression. ␥-Subunit, a small hydrophobic polypeptide that has only one isoform, is involved in the modulation of Na ϩ /K ϩ -ATPase function (10, 11). The ionic homeostasis maintained by the Na ϩ /K ϩ -ATPase is also critical for cell survival, differentiation, and cell apoptosis (12, 13).As an important molecule in charge of so many biological events, Na ϩ /K ϩ -ATPase is regulated by a number of hormones, including aldosterone, thyroid hormone, glucocorticoid, catecholamines, insulin, carbachol, and androgen. These circulating horm...

BackgroundThe prognosis of most hepatocellular carcinoma (HCC) patients is poor due to the high metastatic rate of the disease. Understanding the molecular mechanisms underlying HCC metastasis is extremely urgent. The role of CD24 and NDRG2 (N-myc downstream-regulated gene 2), a candidate tumor suppressor gene, has not yet been explored in HCC.MethodsThe mRNA and protein expression of CD24 and NDRG2 was analyzed in MHCC97H, Huh7 and L-02 cells. Changes in cell adhesion, migration and invasion were detected by up- or down-regulating NDRG2 by adenovirus or siRNA. The expression pattern of NDRG2 and CD24 in HCC tissues and the relationship between NDRG2 and HCC clinical features was analyzed by immunohistochemical and western blotting analysis.ResultsNDRG2 expression was negatively correlated with malignancy in HCC. NDRG2 exerted anti-tumor activity by regulating CD24, a molecule that mediates cell-cell interaction, tumor proliferation and adhesion. NDRG2 up-regulation decreased CD24 expression and cell adhesion, migration and invasion. By contrast, NDRG2 down-regulation enhanced CD24 expression and cell adhesion, migration and invasion. Immunohistochemical analysis of 50 human HCC clinical specimens showed a strong correlation between NDRG2 down-regulation and CD24 overexpression (P = 0.04). In addition, increased frequency of NDRG2 down-regulation was observed in patients with elevated AFP serum level (P = 0.006), late TNM stage (P = 0.009), poor differentiation grade (P = 0.002), tumor invasion (P = 0.004) and recurrence (P = 0.024).ConclusionsOur findings indicate that NDRG2 and CD24 regulate HCC adhesion, migration and invasion. The expression level of NDRG2 is closely related to the clinical features of HCC. Thus, NDRG2 plays an important physiological role in HCC metastasis.

Fat embolism syndrome (FES) after liposuction is likely a life-threatening disorder, though its incidence is low. The three chief clinical manifestations include respiratory insufficiency, cerebral involvement, and petechial rash. Although FES is a multisystem disorder, the most seriously affected organs are the lungs, brain, cardiavascular system, and skin. Many laboratory findings are characteristic but nonspecific. The pathogenesis of FES after liposuction has been looked at both mechanically and biochemically. Diagnosis is difficult; Gurd and Wilson's diagnostic criteria based on clinical examination is still extensively used in clinics at present. There is no specific therapy for FES after liposuction for the moment, so prevention, early diagnosis, and supportive therapies are important. In this article we discuss the clinical presentation, pathogensis, and current methods to prevent FES and, if possible, ways to treat this complication.

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Organometal halide perovskite solar cells (PSCs) have shown high photovoltaic performance but poor utilization of ultraviolet (UV) irradiation. Lanthanide complexes have a wide absorption range in the UV region and they can down-convert the absorbed UV light into visible light, which provides a possibility for PSCs to utilize UV light for higher photocurrent, efficiency, and stability. In this study, we use a transparent luminescent down-converting layer (LDL) of Eu-4,7-diphenyl-1,10-phenanthroline (Eu-complex) to improve the light utilization efficiency of PSCs. Compared with the uncoated PSC, the PSC coated with Eu-complex LDL on the reverse of the fluorine-doped tin oxide glass displayed an enhancement of 11.8% in short-circuit current density (J) and 15.3% in efficiency due to the Eu-complex LDL re-emitting UV light (300-380 nm) in the visible range. It is indicated that the Eu-complex LDL plays the role of enhancing the power conversion efficiency as well as reducing UV degradation for PSCs.