•We show that the bending moments are reduced but the deflections are increased by increasing the temperature.•We show that nonlinear bending behaviors of CNTRC panels are significantly influenced by ...the CNT volume fraction.•We show that nonlinear bending behaviors of CNTRC panels are significantly influenced by the foundation stiffness.•Nonlinear bending behaviors of CNTRC panels are significantly influenced by the character of inplane boundary conditions.
Nonlinear bending analysis is presented for nanocomposite cylindrical panels subjected to a transverse uniform or sinusoidal load resting on elastic foundations in thermal environments. Carbon nanotubes are used to reinforce the cylindrical panels in two distinguished patterns, namely, uniformly distributed (UD) and functionally graded (FG) reinforcements. The material properties of CNTRCs are assumed to be temperature-dependent and are estimated by a micromechanical model. The governing equations of the panel are derived based on a higher-order shear deformation theory with a von Kármán-type of kinematic nonlinearity and are solved by a two-step perturbation technique. The nonlinear bending behaviors of the CNTRC panels with different CNT volume fraction distributions, foundation stiffnesses, temperature rise, and the character of in-plane boundary conditions are studied in details.
Epithelial ovarian cancer (EOC) is a highly lethal gynaecological malignancy. Cisplatin is the basal chemotherapeutic agent used to treat EOC, but resistance to cisplatin leads to chemotherapy ...failure. MicroRNAs are a novel class of regulators that function by controlling gene expression at the post-transcriptional level. Several recent reports have identified some microRNAs that are related to chemotherapy sensitivity. In this study, we found two microRNAs miR-152 and miR-185 that were significantly downregulated in the cisplatin-resistant ovarian cell lines SKOV3/DDP and A2780/DDP, compared with their sensitive parent line SKOV3 and A2780, respectively. Subsequently, the roles of miR-152 and miR-185 were evaluated in vitro and in vivo. The overexpression of miR-152 or miR-185 increased cisplatin sensitivity of SKOV3/DDP and A2780/DDP cells by inhibiting proliferation and promoting apoptosis, then we further confirmed that these miRNAs functioned through suppressing DNA methyltransferase 1 (DNMT1) directly. Concordantly, CD-1/CD-1 nude mice that were injected intraperitoneally with SKOV3/DDP cells transfected with miR-152 mimics exhibited upregulated cisplatin sensitivity in vivo. Interestingly, we found that there were no significant changes in the expression of these two microRNAs after treatment with decitabine (DAC), a traditional epigenetic therapeutic agent, suggesting these miRNAs represented two new regulators independent of DAC. Finally, the survival assay in A549 and HepG2 cells revealed that the two microRNAs involved in cisplatin sensitivity were related to cell types. Our results indicated that miR-152 and miR-185 were involved in ovarian cancer cisplatin resistance in vitro and in vivo by targeting DNMT1 directly. These molecules may serve as potential epigenetic therapeutic targets in other cancers.
This paper presents an investigation on the nonlinear behaviors of nanocomposite cylindrical panels subjected to the combined action of uniform lateral pressure and compressive edge loads. The panels ...may rest on elastic foundations and be in a varying temperature environment. The nanocomposite consists of reinforcing carbon nanotubes either uniformly distributed (UD) or functionally graded (FG) along the thickness direction of the panels. The two cases of nonlinear bending of initially compressed cylindrical panels and postbuckling of initially pressurized cylindrical panels are considered. A high-order shear deformation shell theory in association with von Kármán nonlinear strain–displacement relationships is applied to derive the governing equations for the carbon nanotube reinforced composite (CNTRC) panels. Furthermore, the effects of the panel-foundation interaction and the temperature variation are also included in the analysis and the material properties of CNTRC panels are assumed to be temperature-dependent. Numerical results are presented to illustrate the nonlinear bending responses and the postbuckling behaviors of CNTRC cylindrical panels resting on the Pasternak-type elastic foundations. The present solutions also highlight the effects of the CNT volume fraction, temperature rise, foundation stiffness as well as initial stress on the nonlinear behaviors of CNTRC cylindrical panels.
CuO/graphene composite is synthesized from CuO and graphene oxide sheets following reduced by hydrazine vapor. As the electrode material for lithium-ion batteries, CuO nanoparticles with sizes of ...about 30nm homogeneously locate on graphene sheets, and act as spacers to effectively prevent the agglomeration of graphene sheets, keeping their high active surface. In turn, the graphene sheets with good electrical conductivity server as a conducting network for fast electron transfer between the active materials and charge collector, as well as buffered spaces to accommodate the volume expansion/contraction during discharge/charge process. The synergetic effect is beneficial for the electrochemical performances of CuO/graphene composite, such as improved initial coulombic efficiency (68.7%) and reversible capacity of 583.5mAhg−1 with 75.5% retention of the reversible capacity after 50 cycles.
Dysregulated expression of microRNAs (miRNAs) is associated with a variety of diseases, including colorectal cancer. By comparing more than 200 miRNAs in 13 pairs of matched colorectal cancer and ...normal adjacent tissue samples through qRT-PCR and microarray analysis, we found a widespread disruption of miRNA expression during colorectal tumorigenesis. In particular, among a panel of presumed targets generated by in silico analysis that may interact with these aberrantly expressed miRNAs, KRAS oncogene has been further experimentally validated as the target of miR-143. First, an inverse correlation between KRAS protein and miR-143 in vivo was found. Second, KRAS expression in Lovo cells was significantly abolished by treatment with miR-143 mimic, whereas miR-143 inhibitor increased KRAS protein level. Third, luciferase reporter assay confirmed that miR-143 directly recognize the 3'-untranslated region of KRAS transcripts. Four, Lovo cells treated with miR-143 inhibitor showed a stimulated cell proliferation, whereas miR-143 overexpression had an opposite effect. Finally, inhibition of KRAS expression by miR-143 inhibits constitutive phosphorylation of ERK1/2. Taken together, the present study provides the first evidences that miR-143 is significant in suppressing colorectal cancer cell growth through inhibition of KRAS translation.
Neonatal hypothermia has been associated with higher mortality and morbidity; therefore, thermal control following delivery is an essential part of neonatal care. Identifying the ideal body ...temperature in preterm neonates in the first few hours of life may be helpful to reduce the risk for adverse outcomes.
To examine the association between admission temperature and neonatal outcomes and estimate the admission temperature associated with lowest rates of adverse outcomes in preterm infants born at fewer than 33 weeks' gestation.
Retrospective observational study at 29 neonatal intensive care units in the Canadian Neonatal Network. Participants included 9833 inborn infants born at fewer than 33 weeks' gestation who were admitted between January 1, 2010, and December 31, 2012.
Axillary or rectal body temperature recorded at admission.
The primary outcome was a composite adverse outcome defined as mortality or any of the following: severe neurological injury, severe retinopathy of prematurity, necrotizing enterocolitis, bronchopulmonary dysplasia, or nosocomial infection. The relationships between admission temperature and the composite outcome as well as between admission temperature and the components of the composite outcome were evaluated using multivariable analyses.
Admission temperatures of the 9833 neonates were distributed as follows: lower than 34.5°C (1%); 34.5°C to 34.9°C (1%); 35.0°C to 35.4°C (3%); 35.5°C to 35.9°C (7%); 36.0°C to 36.4°C (24%); 36.5°C to 36.9°C (38%); 37.0°C to 37.4°C (19%); 37.5°C to 37.9°C (5%); and 38.0°C or higher (2%). After adjustment for maternal and infant characteristics, the rates of the composite outcome, severe neurological injury, severe retinopathy of prematurity, necrotizing enterocolitis, bronchopulmonary dysplasia, and nosocomial infection had a U-shaped relationship with admission temperature (α > 0 P < .05). The admission temperature at which the rate of the composite outcome was lowest was 36.8°C (95% CI, 36.7°C-37.0°C). Rates of severe neurological injury, severe retinopathy of prematurity, necrotizing enterocolitis (95% CI, 36.3°C-36.7°C), bronchopulmonary dysplasia, and nosocomial infection (95% CI, 36.9°C-37.3°C) were lowest at admission temperatures ranging from 36.5°C to 37.2°C.
The relationship between admission temperature and adverse neonatal outcomes was U-shaped. The lowest rates of adverse outcomes were associated with admission temperatures between 36.5°C and 37.2°C.
The use of phenylephrine as the first-line agent for prevention and treatment of maternal hypotension during cesarean delivery (CD) may reduce cardiac output, posing a theoretical risk to mother and ...fetus. Norepinephrine has been suggested as a potential alternative, because its β-adrenergic effects might result in greater heart rate and cardiac output than phenylephrine. The use of norepinephrine to prevent and treat hypotension during CD is new, and its use as a bolus has not been fully determined in this context. The purpose of this study was to determine the effective norepinephrine dose, when given as intermittent intravenous (IV) boluses, to prevent postspinal hypotension in 90% of women undergoing elective CD (ED90).
This was a prospective, double-blind sequential allocation dose-finding study, using the biased coin up-and-down design. Forty-term pregnant women undergoing elective CD under spinal anesthesia received a set intermittent norepinephrine bolus of either 3, 4, 5, 6, 7, or 8 µg every time their systolic blood pressure (SBP) fell to below 100% of baseline. The primary outcome was the success of the norepinephrine regimen to maintain SBP at or above 80% of baseline, from induction of spinal anesthesia to delivery of the fetus. Secondary outcomes included nausea, vomiting, hypertension (SBP > 120% of baseline), bradycardia (<50 bpm), upper sensory level of anesthesia to ice cold and umbilical artery and vein blood gases. The ED90 and 95% confidence intervals (CIs) were estimated using both truncated Dixon and Mood and isotonic regression methods.
The estimated ED90 of norepinephrine was 5.49 µg (95% CI, 5.15-5.83) using the truncated Dixon and Mood method and 5.80 µg (95% CI, 5.01-6.59) using the isotonic regression method.
The use of intermittent IV norepinephrine boluses to prevent spinal-induced hypotension in elective CD seems feasible and was not observed to be associated with adverse outcomes. Practically, we suggest an ED90 dose of 6 µg. Further work is warranted to elucidate the comparative effects of intermittent IV bolus doses of phenylephrine and norepinephrine, in terms of efficacy and safety.
The nonlinear transient response of functionally graded graphene reinforced composite (FG-GRC) laminated plates resting on visco-Pasternak foundations in thermal environments under impact load is ...investigated in this paper. Each layer of a laminated plate is assumed to have the same thickness, but the volume fraction of graphene is assumed to be functionally graded in a piece-wise pattern along the plate thickness direction. The stiffness of FG-GRC is then obtained by an extended Halpin-Tsai model, where the graphene efficiency parameters are introduced and determined by molecular dynamics (MD) simulations. The impactor is assumed to be a metal sphere and the contact process between the impactor and the laminated plate is described by a modified Hertz model. The effects of the visco-Pasternak foundation and the temperature variation as well as the initial load are taken into consideration. In the framework of von Kármán type of kinematic nonlinearity, the motion equations of an FG-GRC laminated plate are established based on a higher-order shear deformation theory and solved by a two-step perturbation technique. Finally, the motion equations of the impactor and the FG-GRC laminated plate can be simultaneously solved by the Runge-Kutta approach. The numerical results illustrate the effects of functionally graded graphene distribution, foundation stiffness, temperature variation, initial in-plane load and different impactor velocities on the contact force and the deflection of the FG-GRC laminated plate.
This Article is concerned with the interfacial thermal resistance for polymer composites reinforced by various covalently functionalized graphene. By using molecular dynamics simulations, the ...obtained results show that the covalent functionalization in graphene plays a significant role in reducing the graphene–paraffin interfacial thermal resistance. This reduction is dependent on the coverage and type of functional groups. Among the various functional groups, butyl is found to be the most effective one in reducing the interfacial thermal resistance, followed by methyl, phenyl, and formyl. The other functional groups under consideration such as carboxyl, hydroxyl, and amines are found to produce negligible reduction in the interfacial thermal resistance. For multilayer graphene with a layer number up to four, the interfacial thermal resistance is insensitive to the layer number. The effects of the different functional groups and the layer number on the interfacial thermal resistance are also elaborated using the vibrational density of states of the graphene and the paraffin matrix. The present findings provide useful guidelines in the application of functionalized graphene for practical thermal management.
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