Interface Modulation for the Heterointegration of Diamond on Si.

Along with the increasing integration density and decreased feature size of current semiconductor technology, heterointegration of the Si-based devices with diamond has acted as a promising strategy to relieve the existing heat dissipation problem. As one of the heterointegration methods, the microwave plasma chemical vapor deposition (MPCVD) method is utilized to synthesize large-scale diamond films on a Si substrate, while distinct structures appear at the Si-diamond interface. Investigation of the formation mechanisms and modulation strategies of the interface is crucial to optimize the heat dissipation behaviors. By taking advantage of electron microscopy, the formation of the epitaxial ß-SiC interlayer is found to be caused by the interaction between the anisotropically sputtered Si and the deposited amorphous carbon. Compared with the randomly oriented ß-SiC interlayer, larger diamond grain sizes can be obtained on the epitaxial ß-SiC interlayer under the same synthesis condition. Moreover, due to the competitive interfacial reactions, the epitaxial ß-SiC interlayer thickness can be reduced by increasing the CH4 /H2 ratio (from 3% to 10%), while further increase in the ratio (to 20%) can lead to the broken of the epitaxial relationship. The above findings are expected to provide interfacial design strategies for multiple large-scale diamond applications.

Centimeter-sized diamond composites with high electrical conductivity and hardness.

Achieving high-performance materials with superior mechanical properties and electrical conductivity, especially in large-sized bulk forms, has always been the goal. However, it remains a grand challenge due to the inherent trade-off between these properties. Herein, by employing nanodiamonds as precursors, centimeter-sized diamond/graphene composites were synthesized under moderate pressure and temperature conditions (12 GPa and 1,300 to 1,500 °C), and the composites consisted of ultrafine diamond grains and few-layer graphene domains interconnected through covalently bonded interfaces. The composites exhibit a remarkable electrical conductivity of 2.0 × 104 S m-1 at room temperature, a Vickers hardness of up to ~55.8 GPa, and a toughness of 10.8 to 19.8 MPa m1/2. Theoretical calculations indicate that the transformation energy barrier for the graphitization of diamond surface is lower than that for diamond growth directly from conventional sp2 carbon materials, allowing the synthesis of such diamond composites under mild conditions. The above results pave the way for realizing large-sized diamond-based materials with ultrahigh electrical conductivity and superior mechanical properties simultaneously under moderate synthesis conditions, which will facilitate their large-scale applications in a variety of fields.

Self-Catalyzed Hydrogenated Carbon Nano-Onions Facilitates Mild Synthesis of Transparent Nano-Polycrystalline Diamond.

Transparent nano-polycrystalline diamond (t-NPD) possesses superior mechanical properties compared to single and traditional polycrystalline diamonds. However, the harsh synthetic conditions significantly limit its synthesis and applications. In this study, a synthesis routine is presented for t-NPD under low pressure and low temperature conditions, 10 GPa, 1600 °C and 15 GPa, 1350 °C similar with the synthesis condition of organic precursor. Self-catalyzed hydrogenated carbon nano-onions (HCNOs) from the combustion of naphthalene enable synthesis under nearly industrial conditions, which are like organic precursor and much lower than that of graphite and other carbon allotropes. This is made possible thanks to the significant impact of hydrogen on the thermodynamics, as it chemically facilitates phase transition. Ubiquitous nanotwinned structures are observed throughout t-NPD due to the high concentration of puckered layers and stacking faults of HCNOs, which impart a Vickers hardness about 140 GPa. This high hardness and optical transparency can be attributed to the nanocrystalline grain size, thin intergranular films, absence of secondary phase and pore-free features. The facile and industrial-scale synthesis of the HCNOs precursor, and mild synthesis conditions make t-NPD suitable for a wide range of potential applications.

A Historical Review of Collaborative Learning and Cooperative Learning.

Collaborative learning and cooperative learning are two separate approaches developed independently by two groups of scholars around the same period of time in the 1960 and 1970 s. Due to their different origins and intertwined paths of development, they have their own distinct features while sharing many similarities. The relationship between collaborative learning and cooperative learning can be confusing. Therefore, this paper provides a brief historical review of collaborative learning and cooperative learning to identify the origins of each, where they diverge from each other, and where they are aligned. This paper examines the definitions of the two terms and compares their characteristics. This is followed by a discussion of their historical development in the last fifty years: early development between the 1960 and 1970 s; maturation in the 1980 and 1990 s; convergence in the mid-1990s; and the emergence of Computer-Supported Collaborative Learning (CSCL) in the late 1980s. Finally, this paper summarizes the four paradigms of mainstream research on collaborative and cooperative learning, namely, the "effect" paradigm, the "conditions" paradigm, the "interaction" paradigm, and the "design" paradigm.

Pentaheptite diamond: a new carbon allotrope.

The search forsp3-hybridized carbon allotropes other than diamond has attracted extensive interest because of their fascinating properties. In this paper, an orthorhombic carbon phase insp3bonding, named pentaheptite diamond, by combining the particle swarm optimization method with first-principles calculations has been predicted. The phonon spectra, total energy and elastic constants calculations of the pentaheptite diamond confirm its dynamical, thermal and mechanical stability at zero pressure, respectively. It possesses a high bulk modulus of 385 GPa and Vickers hardness of 72.6 GPa, comparable to diamond. Electronic band structure calculations show that the pentaheptite diamond has a direct band gap of 4.18 eV.

An electrically conductive and ferromagnetic nano-structure manganese mono-boride with high Vickers hardness.

The combination of various desired physical properties greatly extends the applicability of materials. Magnetic materials are generally mechanically soft, yet the combination of high mechanical hardness and ferromagnetic properties is highly sought after. Here, we report the synthesis and characterization of nanocrystalline manganese boride, CrB-type MnB, using the high-pressure and high-temperature method in a large volume press. CrB-type MnB shares the specificity of large numbers of unpaired electrons of manganese ions and strong covalent boron zigzag chains. Thus, manganese mono-boride exhibits "strong" ferromagnetic, magnetocaloric behavior, and possesses high Vickers hardness. We demonstrate that zigzag boron chains in this structure not only play a pivotal role in strengthening mechanical properties but also tuning the exchange correlations between manganese atoms. Nontoxic and Earth-abundant CrB-type MnB is much more incompressible and tougher than traditional ferromagnetic materials. The unique combination of high mechanical hardness, magnetism, and electrical conductivity properties makes it a particularly promising candidate for a wide range of applications.

Humidity Sensors Realized via Negative Photoconductivity Effect in Nanodiamonds.

Herein, the negative photoconductivity (NPC) effect has been observed in nanodiamonds (NDs) for the first time, and with illumination under a 660 nm laser lamp, the conductivity of the NDs decreases significantly. The NPC effect has been attributed to the trapping of carriers by the absorbed water molecules on the ND surfaces. A humidity sensor has been constructed based on the NPC effect of the NDs, and the sensitivity of the sensor can reach 106%, which is the highest value ever reported for carbon-based humidity sensors.

Monoamine Oxidase A is a Major Mediator of Mitochondrial Homeostasis and Glycolysis in Gastric Cancer Progression.

OBJECTIVE: Monoamine oxidase A (MAO-A) is a mitochondrial protein involved in tumourigenesis in different types of cancer. However, the biological function of MAO-A in gastric cancer development remains unknown. METHODS: We examined MAO-A expression in gastric cancer tissues and in gastric cancer cell lines by immunohistochemistry and Western blot analyses. CCK8, FACS and bromodeoxyuridine incorporation assays were performed to assess the effects of MAO-A on gastric cancer cell proliferation. The role of MAO-A in mitochondrial function was determined through MitoSOX Red staining, ATP generation and glycolysis assays. RESULTS: In the present study, we observed that MAO-A was significantly upregulated in gastric cancer tissues and in AGS and MGC803 cells. The observed MAO-A inhibition indicated decreased cell cycle progression and proliferation. Silencing MAO-A expression was associated with suppressed migration and invasion of gastric cancer cells in vitro. Moreover, alleviated mitochondrial damage in these cells was demonstrated by decreased levels of mitochondrial reactive oxygen species and increased ATP generation. MAO-A knockdown also regulated the expression of the glycolysis rate-limiting enzymes hexokinase 2 and pyruvate dehydrogenase. Finally, we observed that the glycolysis-mediated effect was weakened in AGS and MGC803 cells when MAO-A was blocked. CONCLUSION: The findings of the present study indicate that MAO-A is responsible for mitochondrial dysfunction and aerobic glycolysis, which in turn leads to the proliferation and metastasis of human gastric tumour cells.

CSNK2A1 Promotes Gastric Cancer Invasion Through the PI3K-Akt-mTOR Signaling Pathway.

OBJECTIVE: Casein kinase 2 a1 (CSNK2A1) has been shown to be involved in tumorigenesis by enhancing several oncogenic signaling pathways in various cancers. However, the function and mechanism of CSNK2A1 in gastric cancer remain unclear, and this study aimed to elucidate the role of CSNK2A1 in gastric cancer. METHODS: CSNK2A1 expression was assessed by Western blot and qPCR in four gastric cancer (GC) cell lines and one normal gastric epithelial cell line. Stable cancer cell lines with CSNK2A1 gene overexpression or knockdown were established to investigate the function and mechanism of CSNK2A1 in GC cells. RESULTS: CSNK2A1 expression was higher in GC cells than in normal gastric epithelial cells. Stable overexpression of CSNK2A1 in SNU216 cells significantly increased cellular proliferation, invasion, and migration. Silencing CSNK2A1 expression in SGC-790 cells effectively inhibited its oncogenic function. We further verified that epithelial-mesenchymal transition (EMT) was affected by CSNK2A1 and that CSNK2A1 promotes GC cell invasion through the PI3K-Akt-mTOR signaling pathway. CONCLUSION: Our findings suggested that CSNK2A1 plays important oncogenic roles in GC invasion via EMT and the PI3K-Akt-mTOR signaling pathway and that CSNK2A1 may serve as a novel prognostic and/or therapeutic target in GC.

Design and understanding of core/branch-structured VS2 nanosheets@CNTs as high-performance anode materials for lithium-ion batteries.

Revealing the electrochemical property-structure relationship and observing the dynamic structural evolution of electrode materials are critically important for battery performance improvement and the corresponding mechanistic understanding. Here, highly crystalline VS2 nanosheets/carbon nanotubes (CNTs) with a core/branch structure were synthesized, exhibiting reversible discharge capacity of ∼850 mA h g-1 at 200 mA g-1, high coulombic efficiency of ∼98%, good cycling stability and superior rate capability. The relationship between the electrochemical properties and the corresponding dynamic microstructural evolution was further revealed with the in situ electron microscopy technique. Our results showed that the intercalation process with the formation of amorphous LixVS2 and the subsequent conversion reactions with the formation of crystalline Li2S and V nanocrystals occurred during the discharging process. Crystalline Li2S was oxidized in the charging process. The core/branched structure ensured a large exposed surface area of the VS2 nanosheets and provided extra space to accommodate the volume expansion. Meanwhile, the CNTs surrounded by VS2 nanosheets not only provided a continuous and fast conducting pathway for carriers throughout the electrodes, but also enhanced the mechanical stability of the electrode material. These factors finally contributed to the superior electrochemical performance of the core/branch-structured VS2/CNTs electrode.

Novel Superhard sp

Design and synthesis of new carbon allotropes have always been important topics in condensed matter physics and materials science. Here we report a new carbon allotrope, formed from cold-compressed C_{70} peapods, which most likely can be identified with a fully sp^{3}-bonded monoclinic structure, here named V carbon, predicted from our simulation. The simulated x-ray diffraction pattern, near K-edge spectroscopy, and phonon spectrum agree well with our experimental data. Theoretical calculations reveal that V carbon has a Vickers hardness of 90 GPa and a bulk modulus ∼400 GPa, which well explains the "ring crack" left on the diamond anvils by the transformed phase in our experiments. The V carbon is thermodynamically stable over a wide pressure range up to 100 GPa, suggesting that once V carbon forms, it is stable and can be recovered to ambient conditions. A transition pathway from peapod to V carbon has also been suggested. These findings suggest a new strategy for creating new sp^{3}-hybridized carbon structures by using fullerene@nanotubes carbon precursor containing odd-numbered rings in the structures.

Association between the expression levels of tumor necrosis factor-α-induced protein 8 and the prognosis of patients with gastric adenocarcinoma.

The present study aimed to investigate the expression levels of tumor necrosis factor-α-induced protein 8 (TNFAIP8) in gastric adenocarcinoma. TNFAIP8 expression levels in gastric adenocarcinoma tissue samples (with and without lymph node metastasis), adjacent normal tissue samples and metastatic lymph node tissue samples were detected by immunohistochemistry. The correlation between TNFAIP8 expression levels and clinicopathological data and gastric adenocarcinoma prognosis was analyzed. The results demonstrated that TNFAIP8 expression in gastric adenocarcinoma tissue samples and metastatic lymph node tissue samples markedly increased at a rate of 47.2% (50/106) and 81.7% (49/60), respectively, as compared with the adjacent normal tissue samples in which no TNGFAIP8 expression was detected (0%). This increase in TNFAIP8 expression was statistically significant. TNFAIP8 expression rates in the primary tumors (60%, 36/60) of patients with lymph node metastasis were significantly higher compared with the primary tumors of patients without lymph node metastasis (30.4%, 14/46). TNFAIP8 expression was associated with an increase in the severity of TNM stage, tumor grade, vascular invasion, lymph node metastasis and serum CA72-4 levels. The overall survival rate of patients with gastric adenocarcinoma and high TNFAIP8 expression was poorer compared with patients with low TNFAIP8 expression, and TNFAIP8 expression was negatively correlated with patient prognosis. The results also demonstrated that TNFAIP8 was an independent prognostic marker in gastric adenocarcinoma (relative risk, 1.736; P=0.029). In conclusion, the results of the present study demonstrated that TNFAIP8 expression was associated with the occurrence, development and metastasis of gastric adenocarcinoma, and negatively correlated with the prognosis of patients with gastric adenocarcinoma. TNFAIP8 may therefore serve as a prognostic factor for gastric adenocarcinoma.

Circulating microRNA-125b and microRNA-130a expression profiles predict chemoresistance to R-CHOP in diffuse large B-cell lymphoma patients.

Numerous studies have reported the aberrant expression profiles of microRNAs (miRNAs) in diffuse large B-cell lymphoma (DLBCL), although very few of these studies were concerned with chemoresistance to R-CHOP in DLBCL patients. This study was designed to assess the correlation between circulating miRNA expression and chemoresistance and prognosis in DLBCL patients. At the start of the study, we demonstrated that miRNA expression levels in serum were significantly associated with those in formalin-fixed, paraffin-embedded tissues, which indicated that circulating miRNAs may be powerful, non-invasive biomarkers reflecting miRNAs levels isolated from tumor tissue. Then from eight potential drug-resistant miRNAs which were deregulated in DLBCL and which had been reported to be associated with drug resistance in other carcinomas, we screened out the circulating miR-125b and miR-130a, which may related to R-CHOP resistance. Dynamic monitoring of the levels of circulating miR-125b and miR-130a further demonstrated that they were involved in recurrence, progression and chemoresistance in DLBCL patients. Finally, we demonstrated that high miR-125b indicated poor prognosis, as patients with higher miR-125b levels had a shorter overall survival. To our knowledge, this is the first study demonstrating that miR-125b and miR-130a are associated with the risk of chemoresistance in DLBCL patients, and that dynamic monitoring of the levels of circulating miR-125b and miR-130a predicts the therapeutic response and disease status of DLBCL patients.

Unexpected photoluminescence properties from one-dimensional molecular chains.

Unlike bulk iodine, iodine molecular chains formed inside one dimensional (1D) nanochannels of AlPO4-5 (AFI) single crystals show unexpected PL behavior. Thanks to its unique 1D structure, the PL exhibits obvious polarization both in excitation and emission, by changing the angle between the c-axis of the channels and the polarization direction of the incident laser. As pressure increases, the PL intensity increases obviously due to the population increase of (I2)n chains upon compression. In contrast, the breaking of the (I2)n chain at high temperature leads to the decrease of PL intensity. Our theoretical calculation further points out that the PL may arise from the intrinsic band structure of (I2)n chains.

Tailoring Building Blocks and Their Boundary Interaction for the Creation of New, Potentially Superhard, Carbon Materials.

A strategy for preparing hybrid carbon structures with amorphous carbon clusters as hard building blocks by compressing a series of predesigned two-component fullerides is presented. In such constructed structures the building blocks and their boundaries can be tuned by changing the starting components, providing a way for the creation of new hard/superhard materials with desirable properties.

CIZ1 regulates the proliferation, cycle distribution and colony formation of RKO human colorectal cancer cells.

Cip1-interacting zinc finger protein 1 (CIZ1) is a nuclear protein that was observed to bind to p21Cip1/Waf1. p21Cip1/Waf1 regulates the cell cycle and is associated with colorectal cancer (CRC) progression. However, the effect of CIZ1 on CRC cells remains unclear. In the present study, CIZ1 was observed to be highly expressed in RKO human CRC cells. Silencing of CIZ1 using small interfering RNA (siRNA) suppressed RKO cell proliferation. Flow cytometric analysis demonstrated that knockdown of CIZ1 decreased the percentage of cells in the S phase and increased the ratio of cells in the G0/G1 phase in parallel with upregulated cell apoptosis. Moreover, the number and size of RKO cell colonies was repressed by knockdown of the CIZ1 gene. These results suggested that CIZ1 may be involved in colon cancer progression by regulating cell proliferation, cell cycle, apoptosis and colony formation. Furthermore, CIZ1­siRNA may provide a novel tool for CRC investigation and therapy.

Ligustrazine as a salvage agent for patients with relapsed or refractory non-Hodgkin's lymphoma.

BACKGROUND: The prognosis is poor for patients with relapsed or refractory non-Hodgkin's lymphoma (NHL). The main reason for poor prognosis is multidrug resistance (MDR), for which the main phenotype is overexpression of P-glycoprotein (P-gp). This study explored the efficacy of ligustrazine as a salvage agent in patients with relapsed or refractory NHL, and the relationship to P-gp expression. METHODS: Sixty patients were randomized to a reversal agent group, receiving ligustrazine plus chemotherapy, and a control group, receiving chemotherapy alone. Flow cytometry was performed to evaluate P-gp expression. RESULTS: In the 56 patients we were able to evaluate, there was no statistically significant difference in progression-free survival (PFS) in the two groups (P = 0.0651), but the reversal agent group had a higher overall response rate (ORR) than did the control group (P = 0.048). Forty-one of 56 patients had P-gp(+) tumor cells. Among these patients, six of eighteen patients in the reversal agent group and in the control group had complete remission or complete remission/unconfirmed (CR+CRu) reflecting a significant advantage in the reversal agent group (P = 0.048). Patients with P-gp(+) tumor cells in the reversal agent group had a higher overall response rate (ORR) than did the control group (11/18 vs. 6/23, P = 0.024). Kaplan-Meier Survival curve and log-rank test demonstrated that patients with P-gp(+) tumor cells in the reversal agent group had longer progression-free survival than did the control group (P = 0.0464). A small number of patients who received ligustrazine had a decrease in blood pressure. CONCLUSION: Ligustrazine as a salvage agent in combination with chemotherapy can elevate response rate, prolong PFS with manageable toxicity, and correlate with P-gp expression in relapsed or refractory NHL.

[Low dose-intensity docetaxel monotherapy for patients with anthracycline-resistant metastatic breast cancer in poor physical status].

OBJECTIVE: To evaluate the efficacy and safety of a weekly schedule of low dose-intensity docetaxel monochemotherapy for patients with anthracycline-resistant metastatic breast cancer (MBC) in poor physical status. METHODS: Thirty MBC patients who were previously exposed to anthracycline treatment received docetaxel alone at a dose of 30 mg/m2 on D1, D8 and D15, repeated every 4 weeks for a maximum of 6 cycles. RESULTS: Of the 30 evaluable patients, 2 (6.7%) achieved a complete response, and 9 (30.0%) a partial response, with an overall objective response rate of 36.7% (95% CI: 20.5%-53.9%). The most common adverse event was hematologic toxicity. After an average follow-up of 15.0 months, the median time to progression (TTP) was 8. 5 months and the median overall survival (OS) had not reached yet at the end of follow-up. CONCLUSION: The weekly low dose-intensity docetaxel monochemotherapy is effective and well-tolerated in patients with anthracycline-resistant metastatic breast cancer in poor physical status.

Biweekly oxaliplatin in combination with continuous infusional 5-fluorouracil and leucovorin (modified FOLFOX-4 regimen) as first-line chemotherapy for elderly patients with advanced gastric cancer.

OBJECTIVE: The aim of the study was to assess the toxicity and the clinical activity of biweekly oxaliplatin (OXA) in combination with continuous infusional 5-fluorouracil (5-FU) and leucovorin (LV) administered every 2 weeks (modified FOLFOX-4 regimen) in elderly patients with advanced gastric cancer (AGC). PATIENTS AND METHODS: A total of 44 previously untreated AGC patients aged 65 or older were treated with OXA 85 mg m-2 on day 1, LV 200 mg m-2 as a 2-hour infusion followed by a 22-hour infusion of 5-FU 1000 mg m using a multichannel programmable pump, repeated for 2 consecutive days every 2 weeks. RESULTS: All patients were assessable for toxicity and 40 patients for response. Median age was 69 years (65-83). The response rate according to Response Evaluation Criteria in Solid Tumors (RECIST) criteria was 52.5% (95% confidence interval: 44.6%-68.0%) with 3 complete responses, 18 partial responses, 11 stable diseases, and 8 progressions. Median time to progression was 6.5 months and median overall survival was 10.0 months. Toxicity was generally mild. Grade 3 hematologic toxicities of neutropenia, anemia, and thrombocytopenia were in 6.8%, 2.3%, and 4.5% of the patients, respectively. No grade 4 hematologic toxicities occurred. Grade 1 peripheral neuropathy was a common event (34.1%), whereas grade 3 peripheral neuropathy was recorded in only 1 (2.3%) patient. An acute hypersensitivity reaction was observed in 1 patient during administration. CONCLUSION: The modified FOLFOX-4 regimen is an active and well-tolerated chemotherapy for elderly patients aged > or =65 years with AGC. OXA may occasionally cause mild hypersensitivity.

[Relationship between endostatin and vascular cell adhesion molecule-1 expressions on bone marrow stromal cells in BMT-mice].

This study was aimed to investigate the relationship between endostatin and vascular cell adhesion molecule-1 (VCAM-1) expressions on bone marrow stromal cells (BMSC) in mice after bone marrow transplantation (BMT) and effect of ligustrazine on their expressions. The mice were randomly divided into 3 groups: normal group (without treatment), saline group (control of BMT) and ligustrazine group (BMT + ligustrazine). BMT mouse models were established. The normal group was not treated, the saline group was given normal saline (0.2 ml/mouse, twice a day) through gastric tube, while the ligustrazine group was given ligustrazine (0.2 ml/mouse, twice a day) also through gastric tube. On day 7, 14, 21 and 28 after BMT, mice were killed by euthanasia. The expression levels of endostatin and VCAM-1 in bone marrow stromal cells were detected by immunohistochemistry and RT-PCR analysis respectively. The results showed that the endostatin protein mainly expressed in nuclei of BMSCs, the VCAM-1 protein mainly expressed in plasma of BMSCs. On day 7, 14, 21 after BMT the expression levels of endostatin mRNA and protein in ligustrazine and saline groups were significantly lower than that in normal group (P < 0.01 or P < 0.05), while their expression levels in ligustrazine group were lower than that in saline group. On day 28 the expression levels in saline group returned to normal, while the expression levels in ligustrazine group not were normalized. On day 7, 14, 21 after BMT the expression levels of VCAM-1 mRNA and protein in ligustrazine and saline groups were significantly lower than that in normal group (P < 0.01 or P < 0.05), but their expression levels in ligustrazine group were significantly lighter than that in saline group (P < 0.01 or P < 0.05). On day 28 the VCAM-1 expression level in ligustrazine group returned to normal, while its expression level in saline group not were normalized. The difference between these two groups was significant (P < 0.01). Correlation analysis revealed that there was a negative correlation between endostatin and VCAM-1 expression in saline group, there was a positive correlation between endostatin and VCAM-1 expression in ligustrazine group. It is concluded that the endostatin can influence hematopoiesis in bone marrow by affecting VCAM-1 expression on BMSC and hindering connection between stromal cells and hematopoietic cells as well as extracellular stroma and hematopoietic cells, while ligustrazine can enhance the adhesion molecule expression on stromal cell surface of bone marrow in BMT-mice, accelerate the homing and proliferation of HSPC in bone marrow after BMT, meanwhile can promote the repair of bone marrow microenvironment, accelerate hematopoietic reconstitution of bone marrow after BMT through feedback regulation of endostatin expression of BMSC in BMT-mice.