In Situ Growth of 3D/2D (CsPbBr3/CsPb2Br5) Perovskite Heterojunctions toward Optoelectronic Devices.

Two-dimensional (2D) CsPb2Br5 exhibits intriguing functions in enhancing the performance of optoelectronic devices in terms of environmental stability and luminescence properties when composited with other perovskites in different dimensionalities. We built a type I three-dimensional (3D) CsPbBr3/2D CsPb2Br5 heterojunction through phase transition where CsPbBr3 quantum dots in situ grew into 2D CsPb2Br5. A thorough growth mechanism study in combination with excited state dynamic investigations via femtosecond spectroscopy and first-principles calculations revealed that the type I hierarchy enhanced the stability of the heterojunction and spurred its luminous quantum yield by prolonging the lifetime of photogenerated carriers. Mixing the heterojunction with other phosphors yielded white-light-emitting diodes with a color rendering index of 94%. The work thus not only offered one new avenue for building heterojunctions by using the "soft crystal" nature of perovskites but also disentangled the enhanced luminescence mechanism of the heterojunction that can be harnessed for promising applications in the luminescence and display fields.

The association between MMP-12 82 A/G polymorphism and susceptibility to various malignant tumors: a meta-analysis.

Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases responsible for degrading essentially all components of the extracellular matrix (ECM). Accumulating evidence suggests that MMPs might play a critical role in growth, invasion, and metastasis of malignant tumors. A single nucleotide polymorphism (SNP) in the promoter region of MMP-12, MMP-12 82 A/G (rs2276109), has been recognized to play a critical role in regulating the expression of MMP-12, however, its correlation with tumor susceptibility remains controversial. To address this issue, we performed meta-analysis to investigate the association MMP-12 82 A/G polymorphism and susceptibility of nine malignant tumors from 11 studies, including 6153 cancer patients and 6838 controls. Two reviewers independently screened studies for eligibility and extracted data for included studies. While overall no evident association between MMP-12 82 A/G and tumor susceptibility was observed, subgroup analysis revealed a specific role of G allele in increasing the susceptibility for epithelial ovarian carcinoma (EOC) using the allele model (fixed effects OR = 2.45, 95% CI = 1.46-4.10, P = 0.001) and the dominant model (fixed effects OR = 2.52, 95% CI = 1.49-4.24, P = 0.001). We thus suggest that G allele of MMP-12 82 A/G polymorphism is a genetic risk factor for EOC.

Enhanced expression of stem cell markers and drug resistance in sphere-forming non-small cell lung cancer cells.

There is growing evidence suggesting that cancer stem cells (CSCs) are playing critical roles in tumor progression, metastasis and drug resistance. However, the role of CSCs in non-small cell lung cancer (NSCLC) remains elusive. In this study, we enriched for stem-like cells from tumor spheres derived from NSCLC cell line A549 cultured in serum-free medium. Our results showed that sphere-derived cells expressed various stem cell markers such as CD44, CD133, Sox2 and Oct4. Compared with the corresponding cells in monolayer cultures, sphere-derived cells showed marked morphologic changes and increased expression of the stem cell markers CD133. Furthermore, we found that sphere-derived cells exhibited increased proliferation, cell-cycle progression as well as drug-resistant properties as compared to A549 adherent cells. Consistently, expression of several drug resistance proteins, including lung resistance-related protein (LRP), glutathion-S-transferase-π (GST-π) and multidrug resistance proteins-1 (MRP1) were all significantly enhanced in sphere-derived cells. These results indicate the enrichment of CSCs in sphere cultures and support their role in regulating drug resistance in NSCLC.

NRSN2 promotes non-small cell lung cancer cell growth through PI3K/Akt/mTOR pathway.

Neurensin-2 (NRSN2), a small neural membrane protein which localized in small vesicles in neural cells. Recent report suggested that Neurensin-2 might play a suppressive role in tumor. While the biological functions and molecular mechanisms in cancer progression remain unknown. We retrieved Oncomine Database and found that NRSN2 is commonly highly expressed in non-small cell lung cancer (NSCLC). We examined the levels of NRSN2 in 18 pairs of NSCLC and adjacent tissues and found that NRSN2 was overexpressed in malignant tissues. Both loss and gain of function experiments in NSCLC cell lines suggest that NRSN2 promotes cell growth, but no effects in cell invasion. Further investigation show that NRSN2 could affect phosphatidylinositol 3 kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signaling. Taken together, our findings suggest that NRSN2 promotes non-small cell lung cancer cell growth through PI3K/Akt/mTOR pathway.

Wnt/ß-catenin pathway might underlie the MET in trans- differentiation from MSC to MSC-derived neuron.

OBJECTIVE: To observe MET-associated alteration during the trans-differentiation from MSCs to neuron-like cells, and to explore the possible molecular mechanism. METHODS: Bone marrow MSCs were isolated from rat femur and purified in continuous cell culture. After induced differentiation to neuron-like cells by the combination of butylated hydroxyanisole (BHA) and dimethyl sulfoxide (DMSO), cells were tested by comparative polymerase chain reaction (PCR) for the relative expression of MET biomarkers and transcription factors, and for cell cycle by flow cytometry. Meanwhile, target genes of Wnt/ß-catenin pathway were also analyzed by comparative PCR to determine the possible involvement. RESULTS: In MSC-induced neuron-like cells, MET-associated transcription factors such as Snail, Slug, ZEB1, ZEB2, and Twist were significantly attenuated in expression level. The Mesenchymal marker Vimentin expression level was increased. Membrane protein E-cad was slightly down-regulated, while N-cad level was marginally elevated. Percentage of proliferating cells (S phase in cell cycle) markedly shrank from 40.42% for MSCs to 6.76% for MSC-derived neuron. Additionally, Wnt/ß-catenin target genes ß-catenin and c-myc were decreasingly expressed. CONCLUSION: Chemically induced trans-differentiation from MSC to neuron caused similar MET-featured alteration in gene expression and proliferation to known MET, which might be underlied by deactivation of Wnt/ß-catenin pathway.

[Abnormalities of meiotic recombination in Han Chinese azoospermic patients].

OBJECTIVE: To analyze defective homologous chromosomal recombination in Han Chinese azoospermic patients. METHODS: Testicular biopsy samples from 7 healthy controls and 7 Han Chinese azoospermic patients including 2 obstructive azoospermia (OA group) and 5 non-obstructive azoospermia (NOA group) were analyzed. Immunofluorescence staining was performed to categorize early stage cells at meiosis prophase and to analyze chromosome pairing and recombination of pachytene spermatocyte. Newly developed meiotic proteins antibodies (anti-SCP3, anti-synaptonemal complex proteins 3, anti-MLH1, anti-Mut-L Homolog 1, anti-CREST, chromosome centromere antibody) were used to identify synaptonemal complex (anti-SCP3), recombination sites (anti-MLH1) and centromere (anti-CREST), respectively. Staging of spermatocyte was determined according to SCP3 formation progression. Qualitative data were compared by a Chi-square test, and ANOVA was used to analyze quantitative data. RESULTS: Respectively, 2346 and 2932 spermatocytes were categorized in the controls and azoospermic patients. The proportions of zygotene cells in both OA group and NOA group were significantly higher than that of the control group. Investigation of 1967 pachytene cells from the controls and 354 pachytene cells from azoospermic patients indicated that the mean MLH1 foci per pachytene cell of NOA group was statistically lower than that of the controls. Compared with the controls, incomplete synaptonemal complexes cells (containing gap and/or split) were significantly increased in the NOA group. CONCLUSION: Delayed meiosis prophase is relatively common in azoospermic patients, and changes in quantity and distribution of recombination foci may be the cause for spermatogenesis arrest in Han Chinese population.

[Effect of double activation on the development of frozen-thawed oocytes after intracytoplasmic sperm injection].

OBJECTIVE: To investigate the influence on developmental potential of frozen-thawed rabbit oocytes with double assisted activation followed by intracytoplasmic sperm injection (ICSI). METHODS: A total of rabbit oocytes were collected and thawed after vitrification cryopreservation. Among all oocytes were cultured for 1 hour followed by ICSI. 156 Survived oocytes were divided into 5 groups randomly. I0634 single activation: 30 oocytes were added with calcium ionomycin (I0634) at 5 micromol/L for 5 minutes; SrCl(2) single activation: 26 oocytes were added with strontium chloride at 10 mmol/L for 10 minutes; I0634 double activation: 33 oocytes were activated by I0634 twice; SrCl(2) double activation: 28 oocytes were activated by strontium chloride twice. CONTROL GROUP: 39 oocytes were not added with any activators. The rate of fertilization, cleavage and blastocysts formation were observed and compared between various groups. RESULT: The rates of fertilization, cleavage and blastocysts formation were in group of SrCl(2) single activation were higher than those of I0634 single activation group without statistical difference (54% vs.33%, 27% vs. 17%, 8% vs. 3%, P < 0.05). However, those above rates in double activation by I0634 were higher significantly than those of single I0634 activation (82% vs. 33%, 55% vs. 17%, 15% vs. 3%, P < 0.05). The rates of fertilization (61%) was higher and the rate of cleavage (21%) and blastocysts formation (7%) were lower in group of SrCl(2) double activation in comparison with group of SrCl(2) single activation without reaching statistical difference (P < 0.05). Notably, the rates of fertilization, cleavage and blastocysts formation in I0634 double activation group were higher than those in group of SrCl(2) double activation with statistical difference (82% vs. 61%, 55% vs. 21%, 15% vs. 7%, P < 0.05). CONCLUSION: It might enhance the potential of fertilization of oocytes and early embryo development treated by double activation following ICSI, however, those activated oocytes demonstrate rapid cleavage.

[Effect of culture time on the spindle and chromosome configurations of human thawed oocytes with slow-cooling and raid-thawing protocol].

OBJECTIVE: To examine the metaphase II spindle and chromosome configurations of human oocytes cultured for different times after thawing. METHODS: Using slow-cooling and raid-thawing protocol combined with 0.3 mol/L sucrose and 1.5 mol/L 1, 2-propanedio 1 (1, 2-PROH) to cryoprotect human mature oocytes (n = 102), the 64 survival oocytes without abnormal zona pellucida and cytoskeletal were randomly assigned to three groups after thawing: group A: culture 1 hour (n = 20), group B: culture 3 hour (n = 22), group C: culture 5 hours (n = 22), the fresh oocytes served as control group (n = 18). Immunocytochemical staining and fluorescence microscopy were used to assess the morphology of the metaphase II spindle and chromosome. RESULTS: (1) The normal spindle rates of groups A, B and C were 10% (2/20), 46% (10/22) and 41% (9/22) respectively, significantly decreased compared with control group (83%, 15/18; P < 0.05). The rates of absent spindle in group A (45%, 9/20) was significantly higher than control group (6%, 1/18; P < 0.01). Also, the rates of absent spindle in group A was higher than groups B (14%, 3/20) and C (14%, 3/20; P < 0.05). However, no significant differences were observed in groups B and C (P > 0.05). (2) A significant increase in abnormal chromosome rate was observed in group A (30%, 0; 6/20) compared to groups B (68%, 15/22), C (64%,14/22) and control group (78%, 14/18; P < 0.05). No differences in chromosome morphology were observed in groups B, C and control group (P > 0.05). CONCLUSIONS: The cryoprotectant protocol leads to a deleterious effect on the organization of the meiotic spindle and chromosome at MII stage. The 3 - 5 hours post-thawing incubation could permit restoration of the meiotic spindles and chromosome.