CDKN2A promoter methylation enhances self-renewal of glioblastoma stem cells and confers resistance to carmustine.

BACKGROUND: Glioblastoma, a highly aggressive form of brain cancer, poses significant challenges due to its resistance to therapy and high recurrence rates. This study aimed to investigate the expression and functional implications of CDKN2A, a key tumor suppressor gene, in glioblastoma cells, building upon the existing background of knowledge in this field. METHOD: Quantitative reverse transcription PCR (qRT-PCR) analysis was performed to evaluate CDKN2A expression in U87 glioblastoma cells compared to normal human astrocytes (NHA). CDKN2A expression levels were manipulated using small interfering RNA (siRNA) and CDKN2A overexpression vector. Cell viability assays and carmustine sensitivity tests were conducted to assess the impact of CDKN2A modulation on glioblastoma cell viability and drug response. Sphere formation assays and western blot analysis were performed to investigate the role of CDKN2A in glioblastoma stem cell (GSC) self-renewal and pluripotency marker expression. Additionally, methylation-specific PCR (MSP) assays and demethylation treatment were employed to elucidate the mechanism of CDKN2A downregulation in U87 cells. RESULT: CDKN2A expression was significantly reduced in glioblastoma cells compared to NHA. CDKN2A overexpression resulted in decreased cell viability and enhanced sensitivity to carmustine treatment. CDKN2A inhibition promoted self-renewal capacity and increased pluripotency marker expression in U87 cells. CDKN2A upregulation led to elevated protein levels of p16INK4a, p14ARF, P53, and P21, which are involved in cell cycle regulation. CDKN2A downregulation in U87 cells was associated with high promoter methylation, which was reversed by treatment with a demethylating agent. CONCLUSION: Our findings demonstrate that CDKN2A downregulation in glioblastoma cells is associated with decreased cell viability, enhanced drug resistance, increased self-renewal capacity, and altered expression of pluripotency markers. The observed CDKN2A expression changes are mediated by promoter methylation. These results highlight the potential role of CDKN2A as a therapeutic target and prognostic marker in glioblastoma.

Piperacillin-tazobactam induced immune hemolytic anemia led to increased renal impairment and eventual death from multiple organ failure in a patient with hypertensive nephropathy: case report and literature review.

BACKGROUND: Piperacillin is one of the most common drugs that cause drug-induced immune hemolytic anemia, but a complete description of the serological features and course of the disease is rare. This study completely describes the serological characteristics and course of a patient with hypertensive nephropathy who developed drug-induced immune hemolytic anemia and worsened renal function during repeated administration of piperacillin-tazobactam. CASE PRESENTATION: A 79-year-old male patient with hypertensive nephropathy who developed severe hemolytic anemia and worsened renal function during intravenous piperacillin-tazobactam anti-infective treatment due to lung infection. Serological tests showed that the result of the direct antiglobulin test for anti-IgG was positive (4 +) and anti-C3d was negative, and the irregular red blood cell antibody screening test was negative. Plasma samples collected at different times from 2 days before to 12 days after the discontinuation of piperacillin-tazobactam administration were incubated with piperacillin solution and red blood cells of O-type healthy blood donors at 37 °C, IgG piperacillin-dependent antibodies were detected, and the highest titer was 128. However, no tazobactam-dependent antibody was detected in any plasma samples. Therefore, the patient was diagnosed with piperacillin-induced immune hemolytic anemia. Although blood transfusion and continuous renal replacement therapy were given, the patient died of multiple organ failure 15 days after the administration of piperacillin-tazobactam was stopped. CONCLUSION: This is the first complete description of the disease course and serological changes of piperacillin-induced immune hemolytic anemia, which is bound to help deepen the understanding of drug-induced immune hemolytic anemia and draw profound lessons from it.

[Effect of High-Volume Leukapheresis on Hematological Indexes of Patients with Hyperleukocytic Leukemia].

OBJECTIVE: To improve the collection efficiency of leukapheresis, explore relatively scientific and objective evaluation indicators for collection effect, and observe the effect of high-volume leukapheresis on blood cells and coagulation function. METHODS: A total of 158 times of high-volume leukapheresis were performed on 93 patients with hyperleukocytic leukemia by using continuous flow centrifugal blood component separator. 1/5-1/4 of total blood volume of the patients was taken as the target value of leukocyte suspension for single treatment. In addition, the total number of white blood cells (WBCs) subtracted, value of WBCs reduction, rate of WBCs reduction, decrease value of WBCs count, decrease rate of WBCs count, amount of hemoglobin (Hb) lost, value of Hb lost, decreased value of Hb, total number of platelet (PLT) lost, the value of PLT loss, and decrease value of PLT count were used to comprehensively evaluate the collection effect of leukapheresis and influence on Hb level and PLT count of the patients. The prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen (Fib) concentration were detected before and after treatment, and the effect of leukapheresis on coagulation function of the patients was observed. RESULTS: The volume of leukocyte suspension collected in a single treatment was 793.01±214.23 ml, the total number of WBCs subtracted was 353.25 (241.99-547.28)×109, the value of WBCs reduction was 86.98 (63.05-143.43)×109/L, the rate of WBCs reduction was 44.24 (28.37-70.48)%, decrease value of WBCs count was 65.73 (37.17-103.97)×109/L, decrease rate of WBCs count was (35.67±23.08)%, the amount of Hb lost was 17.36 (12.12-24.94) g, the value of Hb lost was 4.31 (3.01-6.12) g/L, decreased value of Hb was 4.80 (-1.25-9.33) g/L, total number of PLT lost was 222.79 (67.03-578.31)×109, the value of PLT loss was 54.45 (17.29-139.08)×109/L, and decrease value of PLT count was 26.00 (8.38-62.50)×109/L. Before and after a single treatment, the PT was 14.80 (13.20-16.98) s and 15.20 (13.08-16.90) s (z=-1.520, P>0.05), the aPTT was 35.20 (28.68-39.75) s and 35.40 (28.00-39.75) s (z=-2.058, P<0.05), the TT was 17.50 (16.30-18.80) s and 17.70 (16.70-19.10) s (z=-3.928, P<0.001), and the Fib concentration was 2.87±1.13 g/L and 2.64±1.03 g/L (t=7.151, P<0.001), respectively. CONCLUSION: High-volume leukapheresis can improve the efficiency of leukapheresis while maintaining the relative stability of the patients' circulating blood volume. The degree of influence on the patients' Hb level, PLT count, Fib concentration, and comprehensive coagulation indicators reflecting the patients' intrinsic and cxtrinsic coagulation activity is within the body's compensation range.

Secondary alloanti-D immunization post transfusion of "Asia type" DEL red blood cells.

BACKGROUND: "Asia type" DEL red blood cells (RBCs) express a very weak D antigen and cannot be detected by routine RhD typing. Thus, it is routinely typed as D-negative (D-) blood group and transfused to D- recipients. Here we described a case of secondary alloanti-D immunization that was associated with transfusion of DEL RBCs to D- recipients and was initially considered as primary alloanti-D immunization. CASE PRESENTATION: A 44-year-old D- woman (G2P2) with adenomyosis and anemia underwent transabdominal hysterectomy. She received four units of D- RBCs before operation. Before transfusion, the alloantibody screening test was negative. Four days after the first transfusion, she needed another RBC transfusion. Unexpectedly, the routine pre-transfusion alloantibody screening test became positive and anti-D (titer, 128-fold) was identified, indicating an alloanti-D immunization. The anti-D developed four days after the first transfusion was unexplained, so alloantibody identification was performed on the sample collected before the first transfusion, and weak anti-D combined with anti-E, which was not detectable during the previous routine pre-transfusion alloantibody screening test with non-enzyme-treated screening cells, was identified using bromelain-treated panel cells. The remaining blood samples of first transfusion in bag tails from two donors were collected for RHD genotyping analysis. One donor was later identified as "Asia type" DEL having RHD* 1227 A/01 N.01 genotype. CONCLUSION: Caution should be applied when we conclude that transfusion of "Asia type" DEL RBCs to true D- recipients could induce primary alloanti-D immunization, especially if the short time interval between transfusion and detection of anti-D is observed.

Correlations of Silent Information Regulator of Transcription 1 (SIRT1) Expression, Inflammatory Factors, and Oxidative Stress with Pulmonary Function in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD).

BACKGROUND The aim of this study was to investigate the correlations of silent information regulator of transcription 1 (SIRT1) expression, inflammatory factors, and oxidative stress with pulmonary function in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). MATERIAL AND METHODS Bronchoalveolar lavage fluid (BALF) was collected from 188 patients with COPD (83 in stable phase and 105 in acute exacerbation phase) and 56 healthy controls. Subsequently, the SIRT1 expression levels, the IL-6 and IL-8 levels (the representatives of inflammatory factors), and the MDA and SOD levels (indicative of oxidative stress) were detected via enzyme-linked immunosorbent assay. Correlations of SIRT1 expression, inflammatory factors, and oxidative stress with pulmonary function parameters [forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) and FEV1] were measured via Spearman's correlation analysis. RESULTS The levels of inflammatory factors and oxidative stress were elevated and SIRT1 expression remarkably declined in patients with AECOPD compared with those in healthy controls and stable COPD patients (P<0.05). Spearman's correlation analysis revealed that SIRT1 expression, interleukin (IL)-6, and IL-8 were strongly associated with pulmonary function parameters (FEV1/FVC and FEV1) in patients with AECOPD (P<0.001), while no such obvious correlation was observed in stable COPD patients. CONCLUSIONS Oxidative stress and expression levels of inflammatory factors are evidently elevated and SIRT1 expression declines in patients with AECOPD. Moreover, SIRT1 expression is positively associated with pulmonary function parameters, while IL-6 and IL-8 exhibit negative correlations with pulmonary function parameters.

Adult pulmonary Langerhans cell histiocytosis might consist of two distinct groups: isolated form and extrapulmonary recidivism type.

BACKGROUND: Adult pulmonary Langerhans cell histiocytosis (PLCH) is a rare form of Langerhans cell histiocytosis (LCH) that typically occurs in cigarette smokers. The clinical course of PLCH is unpredictable; the disease may resolve spontaneously, or lead to multi-organ failure and death. To better understand this idiopathic disease, we retrospectively overviewed a cohort of Asian patients with PLCHs. METHODS: Herein, we have provided detailed clinicopathological features and molecular findings of PLCHs in a Southwestern Chinese population, including the expressions of apoptotic protein P16, programmed cell death 1 (PD-1), and programmed cell death-ligand 1 (PD-L1). Importantly, the BRAF V600E mutation was observed in this cohort. RESULTS: In accordance with the follow up data, the cohort was subdivided into two groups, an isolated pulmonary group and extrapulmonary recidivism group. Among the isolated group, the participants were predominantly young males (<40 years old), with a history of smoking, respiratory symptoms (cough and difficulty breathing), showed more cystic lesions in computed tomography (CT) scanning, had more cellular Langerhans granulomas under the microscope, overexpression of P16 (66.7%), high PD-1 (100%) and low PD-L1 (33.3%) expressions, and no BRAF V600E mutation was detected. In contrast, the extrapulmonary recidivism group showed significantly older age (>40 years old), recurrent spontaneous pneumothorax, more nodular changes in CT scanning, more interstitial fibrosis histologically, expression rates of 100% of P16, 66.7% of PD-1, and 33.3% of PD-L1; and importantly, BRAF V600E mutation was detected in 33.3% of this subdivision. CONCLUSIONS: We found that adult PLCH might consist of two distinct groups: an isolated form and extrapulmonary recidivism PLCH. Overexpression of P16 could be a diagnostic biomarker for PLCH. An extremely low mutation rate of the BRAF gene in adult PLCH in our cohort indicated that there might be other pathogeneses for this disease among Asian patients.

[Effect of Highvolume Platelet Reduction Therapy on White Blood Cell Count and Hemoglobin Level in Patients with Thrombocytosis].

OBJECTIVE: To explore the effect of high volume platelet reduction therapy on the white blood cell (WBC) count and hemoglobin (Hb) level in patients with thrombocytosis. METHODS: Thirty-two plateletphoreses were performed for patients with thromocytosis by using ELP or MNC program of blood component isolator of COBE spectra continuous flow concentrifugation and the ACD-A preservation solution for blood as blood anticoagulant. In each treatment of patients, 2.5-3.0 tines total blood volume (TBV) were circulated, then the platelet suspension of 1/5-1/4 time TBV was prepared and collected. RESULTS: A single plateletpheresis took (212.53±41.54) minutes in which (8 812.63±2087.15) ml blood were treated, and (798.84±190.77) ml platelet suspension was collected. In the suspension, the platelet count was 4 486.50 (3 058.50-5 279.50)×109/L, containing 3 455.50 (2 288.68-4 226.71)×109. WBC count was 13.79 (10.21-20.72)×109/L, containing 11.90(7.81-14.40)×109. Hemoglobin concentration was (3.28±1.25) g/L，containing (2.62 ± 1.17) g. Before and after plateletpheresis, the patients' platelet count was 1 263.00 (1 052.50-1 807.50)×109/L and (778.83±247.25)×109/L（Z=4.94, P＜0.01), WBC count was 9.96(6.44-14.01)×109/L and 8.59(5.37, 13.12)×109/L (Z=13.31, P＜0.05), Hemoglobin concentration was (112.63 ± 24.56)g/L and (109.55 ± 24.46)g/L (t=1.68，P＞0.05). CONCLUSION: Using continuous flow centrifugation and blood component separating in plateletpheresis for the patients with thrombocytosis can obviously decrease the high ratio of platelets, and improve the effect of plateletpheresis. The high volume platelet reduction therapy can lead to decrease of WBC count to some alent, degree but WBC count still in the normal range, moreover not affect the hemoglobin level significantly.

Screening of MSI detection loci and their heterogeneity in East Asian colorectal cancer patients.

OBJECTIVE: This study aims to screen the MSI detection loci suitable for the East Asian colorectal cancer patients. and explore its intratumoral heterogeneity. METHODS: A total of 271 pathological tissues specimens of colorectal cancer were collected. The MSI status was detected using different PCR reagent kits with different detection loci. Then, the results were compared with the immunohistochemical (IHC) staining results. Microdissection of pathological tissues specimens detected to be MSI-H was performed to examine whether there was intratumoral heterogeneity of MSI status. RESULTS: Thirty-nine out of 271 cases were dMMR. dMMR occurred mostly in patients with right-hemi colon cancer (P < 0.0001). Compared with dMMR patients, the clinical stages of pMMR patients were more inclined to be in the late stage with lymph node metastasis (P < 0.0001). MSI-H tumors were significantly associated with KRAS mutation (P = 0.036) and PD-L1 expression (P = 0.038). Compared with Promega panel and 24-locus detection, the consistency between NCI MSI panel and IHC staining results were the highest with the Kappa value of 0.850. The sensitivity of detection decreased from 87.18% to 56.41% with the increase in detection loci. Single locus analysis showed that the first two loci with the highest sensitivity were both mononucleotide loci, namely, BAT-26 (95.45%) and BAT-25 (86.36%). The dinucleotide locus with highest sensitivity was D2S123 (50%). The main detection loci of MSI-H showed no intratumoral heterogeneity. CONCLUSION: The combination of 2 mononucleotide loci (BAT25, BAT26) and 3 dinucleotide loci (D2S123, D5S346, D17S250) might be the most suitable loci for MSI detection in East Asian population. There is no intratumoral heterogeneity in the main MSI loci.

PABPC1L depletion inhibits proliferation and migration via blockage of AKT pathway in human colorectal cancer cells.

Numerous studies have demonstrated that PABPC1 participates in the process of carcinogenesis and its function is inconsistent in different types of cancers. PABPC1-like (PABPC1L) is an important paralog of PABPC1 and few studies are available on the roles of PABPC1L in colorectal cancer (CRC) development. Hence, we explored the biological function and prognostic impact of PABPC1L in CRC. The mRNA expression of PABPC1L in CRC was determined based on the data obtained from The Cancer Genome Atlas (TCGA) database. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was utilized to determine the PABPC1L mRNA expression level in CRC HT-29 and LS-174T cell lines. Kaplan-Meier method and Cox proportional-hazards model were utilized to conduct the survival and prognosis analyses. HT-29 cells with silenced PABPC1L were constructed to explore the effect of PABPC1L on cell proliferation, invasion and migration capacities using cell counting kit-8 (CCK-8), clone formation, wound-healing and Transwell assays, respectively. To uncover the potential mechanisms of how PABPC1L influences CRC proliferation and migration, we analyzed the expression of AKT, p-AKT, PI3K, and p-PI3K in HT-29 cells using western blotting. Our results revealed that PABPC1L was overexpressed in CRC tissues compared with normal tissues based on the data obtained from TCGA database. Similarly, the mRNA expression of PABPC1L was higher in HT-29 and LS-174T cells than that in CCD-18Co cells. The expression of PABPC1L in CRC was found to be significantly related to age, pathologic stage, pathologic-node, pathologic-metastasis, and death. In univariate and multivariate analyses, pathologic-tumor and pathologic-metastasis were identified as independent prognostic factors for CRC. After PABPC1L depletion, cell proliferation rate, colony numbers, and the invasive and migratory capacity of HT-29 cells were all reduced. Western blot analysis showed that reduction of PABPC1L significantly inhibited p-AKT, and p-PI3K expression level in HT-29 cells. Collectively, our results suggested that PABPC1L is a potential novel candidate oncogene in CRC, and targeting PABPC1L may provide clinical utility in CRC.

Unique structure and surface-related elastic modulus of alumina nanobelts.

Single-crystalline α-Al2O3 nanobelts were synthesized by high-temperature chemical vapor deposition in a high-purity H2 atmosphere. The crystalline planes for the upper and side surfaces of the nanobelts were [Formula: see text] and [Formula: see text] and the orientations along height, length and width directions were [Formula: see text] [Formula: see text] and [Formula: see text] respectively. The formation of such a unique structure was dependent on the strong reducing atmosphere used in the growth process, and the deactivation of the [Formula: see text] plane by hydrogen could be the primary cause. The elastic modulus of the nanobelts was measured using a thermal resonance method. The moduli for the nanobelts were about 320 GPa for thicknesses above 40 nm, and slightly increased to 356 GPa as the thickness decreased to 31 nm. The slightly low modulus values compared to the theoretical value of 371 GPa is attributed to oxygen vacancies within the nanobelts, while the increase in modulus with decreased thickness comes from the stiffening effect caused by surface relaxation.

MicroRNA-3646 Contributes to Docetaxel Resistance in Human Breast Cancer Cells by GSK-3ß/ß-Catenin Signaling Pathway.

Acquisition of resistance to docetaxel (Doc) is one of the most important problems in treatment of breast cancer patients, but the underlying mechanisms are still not fully understood. In present study, Doc-resistant MDA-MB-231 and MCF-7 breast cancer cell lines (MDA-MB-231/Doc and MCF-7/Doc) were successfully established in vitro by gradually increasing Doc concentration on the basis of parental MDA-MB-231 and MCF-7 cell lines (MDA-MB-231/S and MCF-7/S). The potential miRNAs relevant to the Doc resistance were screened by miRNA microarray. We selected 5 upregulated miRNAs (has-miR-3646, has-miR-3658, has-miR-4438, has-miR-1246, and has-miR-574-3p) from the results of microarray for RT-qPCR validation. The results showed that expression level of miR-3646 in MDA-MB-231/Doc cells was significantly higher than in MDA-MB-231/S cells. Compared to MCF-7/S cells, miR-3646 expression was up-regulated in MCF-7/Doc cells. Further studies revealed that transfection of miR-3646 mimics into MDA-MB-231/S or MCF-7/S cells remarkably increased their drug resistance, in contrast, transfection of miR-3646 inhibitors into MDA-MB-231/Doc or MCF-7/Doc cells resulted in significant reduction of the drug resistance. By the pathway enrichment analyses for miR-3646, we found that GSK-3ß/ß-catenin signaling pathway was a significant pathway, in which GSK-3ß was an essential member. RT-qPCR and Western blot results demonstrated that miR-3646 could regulate GSK-3ß mRNA and protein expressions. Furthermore, a marked increase of both nuclear and cytoplasmic ß-catenin expressions (with phosphorylated-ß-catenin decrease) was observed in MDA-MB-231/Doc cells compared with MDA-MB-231/S cells, and their expression were positively related to miR-3646 and negatively correlated with GSK-3ß. Taken together, our results suggest that miR-3646-mediated Doc resistance of breast cancer cells maybe, at least in part, through suppressing expression of GSK-3ß and resultantly activating GSK-3ß/ß-catenin signaling pathway.

Upregulation of miRNA-17 and miRNA-19 is associated with unfavorable prognosis in patients with T-cell lymphoblastic lymphoma.

Lymphoblastic lymphoma is an aggressive subtype of non-Hodgkin lymphoma. Identification of prognostic factors for these patients, especially for patients with T-cell lymphoblastic lymphoma (T-LBL), remains a challenge. This is largely due to the relative rarity of the disease and lack of adequate samples for biological research. T-LBL is more common in Asia than in Western countries. In an attempt to explore novel prognostic markers for T-LBL, we conducted retrospective study of archived diagnostic specimens from 57 Chinese patients with well-defined diagnosis of T-LBL. Using quantitative real-time reverse transcription-PCR, we analyzed miR-17 and miR-19 expression levels in formalin-fixed and paraffin-embedded lymph node specimens from these patients, together with reactive lymph node controls. We correlated molecular findings to patients' immunophenotype and clinical follow-up information. MYC protein expression was also evaluated in these patients. We found that miR-17 and miR-19 levels were concordant and upregulated in T-LBL in comparison with controls. Statistical analysis showed that higher expression of miR-17 and miR-19, and positive MYC protein results were associated with a shorter overall survival of T-LBL. In addition, miR-17 and miR-19 appeared to be independent prognostic factors for T-LBL. We demonstrate here that upregulation of miR-17 and miR-19 correlates with poor clinical outcome of T-LBL, indicating that miR-17 and miR-19 may be considered as potential unfavorable prognostic markers for T-LBL.

Synthesis and magnetic properties of Fe3C-C core-shell nanoparticles.

Fe3C-C core-shell nanoparticles were fabricated on a large scale by metal-organic chemical vapor deposition at 700 °C with ferric acetylacetonate as the precursor. Analysis results of x-ray diffraction, transmission electron microscope and Raman spectroscope showed that the Fe3C cores with an average diameter of ∼35 nm were capsulated by the graphite-like C layers with the thickness of 2-5 nm. The comparative experiments revealed that considerable Fe3O4-Fe3C core-shell nanoparticles and C nanotubes were generated simultaneously at 600 and 800 °C, respectively. A formation mechanism was proposed for the as-synthesized core-shell nanostructures, based on the temperature-dependent catalytic activity of Fe3C nanoclusters and the coalescence process of Fe3C-C nanoclusters. The Fe3C-C core-shell nanoparticles exhibited a saturation magnetization of 23.6 emu g(-1) and a coercivity of 550 Oe at room temperature.

Correlations between expression levels of thymidylate synthase, thymidine phosphorylase and dihydropyrimidine dehydrogenase, and efficacy of 5-fluorouracil-based chemotherapy for advanced colorectal cancer.

The efficacy of 5-fluorouracil (5-FU)-based chemotherapy for colorectal cancer (CRC) widely varies among patients; therefore, it is difficult to accurately predict chemotherapeutic responses. Some recent studies have found that key enzymes in the various metabolic pathways activated by 5-FU present potential predictors of treatment outcome. Of these enzymes, thymidylate synthase (TS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD) are known to play important roles in the efficacy of therapeutic agents. Here, we measured expression levels of TS, TP, and DPD in formalin-fixed, paraffin-embedded, CRC specimens and paracancerous tissue with normal mucosa by immunohistochemical and fluorescence real-time quantitative polymerase chain reaction techniques. We found no significant differences in TS, TP, and DPD expression levels between CRC specimens and paracancerous tissues (P > 0.05), although overall survival and the chemotherapeutic effect were relatively poor in CRC patients with relatively high expression levels of TS, TP, and DPD, as compared to those with comparatively low expression levels (P < 0.05). Therefore, TS, TP, and DPD mRNA levels appear to be suitable indicators of the efficacy of 5-FU-based chemotherapy and prognosis of CRC.

Fracture strain of SiC nanowires and direct evidence of electron-beam induced amorphisation in the strained nanowires.

SiC nanowires with diameters ranging from 29 to 270 nm exhibit an average strain of 5.5% with a maximum of up to 7.0%. The brittle fracture of the nano-wires being measured was confirmed by transmission electron microscopy (TEM) analysis. This study demonstrates that amorphisation occurs in the stained SiC nanowires during normal TEM examination, which could be induced by electron irradiation.

Fabrication of crystal α-Si3N4/Si-SiOx core-shell/Au-SiOx peapod-like axial double heterostructures for optoelectronic applications.

Novel crystal α-Si(3)N(4)/Si-SiO(x) core-shell/Au-SiO(x) peapod-like axial double heterostructural nanowires were obtained by directly annealing a Au covered SiO(2) thin film on a Si substrate. Our extensive electron microscopic investigation revealed that the α-Si(3)N(4) sections with a mathematical left angle bracket 101 mathematical right angle bracket growth direction were grown first, followed by growth of the Si-SiO(x) core-shell sections and finally growth of the Au-SiO(x) peapod-like sections. Through a series of systematically comparative experiments, a temperature-dependent multi-step vapor-liquid-solid growth mechanism is proposed. Room temperature photoluminescence measurement of individual nanowires reveals two emission peaks (410 and 515 nm), indicating their potential applications in light sources, laser or light emitting display devices.

Crystalline structures and misfit strain inside Er silicide nanocrystals self-assembled on Si(001) substrates.

The morphology and crystalline structure of Er silicide nanocrystals self-assembled on the Si(001) substrate were investigated using scanning tunneling microscopy (STM) and transmission electron microscopy (TEM). It was found that the nanowires and nanorods formed at 630 °C has dominant hexagonal AlB(2)-type structure, while inside the nanoislands self-organized at 800 °C the tetragonal ThSi(2)-type structure is prevalent. The lattice analysis via cross-sectional high-resolution TEM demonstrated that internal misfit strain plays an important role in controlling the growth of nanocrystals. With the relaxation of strain, the nanoislands could evolve from a pyramid-like shape into a truncated-hut-like shape.

Synthesis of sintering-resistant sorbents for CO2 capture.

Sorbents for high temperature CO2 capture are under intensive development owing to their potential applications in advanced zero emission power, sorption-enhanced steam methane reforming for hydrogen production and energy storage systems in chemical heat pumps. One of the challenges in the development is the prevention of sintering of the sorbent (normally a calcium oxide derivative) which causes the CO2 capture capacity of the material to deteriorate rapidly after a few cycles of utilization. Here we show that a simple wet mixing method can produce sintering-resistant sorbents from calcium and magnesium salts of d-gluconic acid. It was found that calcium oxide was well distributed in the sorbents with metal oxide nanoparticles on the surface acting as physical barriers, and the CO2 capture capacity of the sorbents was largely maintained over multiple cycles of utilization. This method was also applied to other organometallic salts of calcium and magnesium/aluminum and the produced sorbents showed similarly high reversibility.

Studies on metallofullerene (Dy@C82) embedded in a DDAB film in aqueous solution.

The electrochemical behavior of metallofullerene (Dy@C82) in didodecyldimethylammonium bromide (DDAB) films deposited on glassy carbon, quartz crystal microbalance (QCM) gold crystals, and indium tin oxide (ITO) electrodes in aqueous solution was investigated in detail. Four pairs of reversible redox peaks were observed, and for the first time, these peaks were characterized by vis/NIR spectroscopy. Different from previous fullerene/cationic lipid modified electrodes, one oxidation and three reduction processes were observed. The stability of Dy@C82 and its ions in the film toward air was detected by measuring its cyclic voltammogram after holding the potentials for 10 s, followed by introducing 10 microL of air to the solution. Dy@C82 and its first three anions are stable toward air and water, while some chemical reactions take place when the third anion is further reduced in the film. Dy@C82+ is less stable than Dy@C82- toward water and air. The electrochemical processes were measured in different electrolytes, which showed pronounced anionic dependence on either its cation or anions. The electrochemical processes were also monitored using electrochemical quartz crystal microbalance (EQCM), and from the result a possible electron-transfer mechanism of a Dy@C82/DDAB electrode in aqueous solution was presented. It showed that the anions of Dy@C82 were bound to the DDA+ cation in the film, while the anions of electrolyte diffused into the film to compensate the positive charges when a cation of Dy@C82 was generated.