Stabilization of carbon nanotubes by filling with inner tubes: An optical spectroscopy study on double-walled carbon nanotubes under hydrostatic pressure

The stabilization of carbon nanotubes via the filling with inner tubes is demonstrated by probing the optical transitions in double-walled carbon nanotube bundles under hydrostatic pressure with optical spectroscopy. Double-walled carbon nanotube films were prepared from fullerene peapods and characterized by HRTEM and optical spectroscopy. In comparison to single-walled carbon nanotubes, the pressure-induced redshifts of the optical transitions in the outer tubes are significantly smaller below $\sim$10 GPa, demonstrating the enhanced mechanical stability due to the inner tube already at low pressures. Anomalies at the critical pressure P$_d$$\approx$12 GPa signal the onset of the pressure-induced deformation of the tubular cross-sections. The value of P$_d$ is in very good agreement with theoretical predictions of the pressure-induced structural transitions in double-walled carbon nanotube bundles with similar average diameters.Comment: 6 pages, 4 figures; to appear in Phys. Rev.

Stress and its associated factors among medical students in a public medical faculty, Malaysia

Background: Stress is common among university students. Levels of stress vary between the students of different courses in the university and many factors are associated with it. As compared to other professional courses, medical students are more prone to get depressed because medical education is known to be stressful and very demanding. Materials and Methods: This is a cross-sectional study using a pretested, self-administered questionnaire involving all medical students in academic session 2013/2014. The questionnaire consists of 3 parts; socio-demographic information, family factors and personal factors; Depression, Anxiety and Stress Score 21 questionnaire (DASS 21) and Duke University Religion Index (DUREL). DUREL measures religiosity in 3 scales namely; organized religious activity (ORA), non-organized religious activity (NORA) and intrinsic religiosity (IR). The questionnaire was distributed to all medical students available in FMHS during the data collection period. Data collected were analyzed using IBM SPSS version 21. Result: Of 409 medical students, 329 (80.4%) responded. Most (50.5%) were aged 22 years and above, majority (62.3%) were female students. Respondents were mainly Malay (54.4%) and Muslims (56.8%). Stress prevalence in medical students were 19.8%. Stress prevalence was higher among students aged ≤ 21 years (22.1%), male (20.2%), Indian (24.0%) and Hindus (31.6%),among students with father of primary education level (21.4%), mother of tertiary education level (25%) and low income family (21.4%). Prevalence of stress among students in pre-clinical year (21.4%) and clinical year students (17.9%), p>0.05. Stress among students who did not undergo matriculation course and those who attended were 21.7% and 18.8%, respectively. Proportion of stress students who entered medical school not on their own choice and on their own choice were 24.3% and 18.5%, respectively, p>0.05. Medical students with poor ORA and NORA showed higher proportion of stress (20.2%, 20.6% respectively) however, students with good IR had higher proportion of stress compared to those with poor IR (20.0%, 19.5%, p>0.05). Conclusion: Stress is prevalent among almost one-fifth of medical students, especially those in their pre-clinical years of studies. Students’ involvement in religious activities could be beneficial to prevent stress. Further research is needed to assess the effect of medical training on stress and the effect of religiosity on stress coping

Carrier-envelope phase control over pathway interference in strong-field dissociation of H2+_2^+

The dissociation of an H$_2^+$ molecular-ion beam by linearly polarized, carrier-envelope-phase-tagged 5 fs pulses at 4$\times10^{14}$W/cm$^2$ with a central wavelength of 730 nm was studied using a coincidence 3D momentum imaging technique. Carrier-envelope-phase-dependent asymmetries in the emission direction of H$^+$ fragments relative to the laser polarization were observed. These asymmetries are caused by interference of odd and even photon number pathways, where net-zero photon and 1-photon interference predominantly contributes at H$^+$+H kinetic energy releases of 0.2 -- 0.45 eV, and net-2-photon and 1-photon interference contributes at 1.65 -- 1.9 eV. These measurements of the benchmark H$_2^+$ molecule offer the distinct advantage that they can be quantitatively compared with \textit{ab initio} theory to confirm our understanding of strong-field coherent control via the carrier-envelope phase

Effect of Combining Electron Beam Irradiation and Alkaline Pretreatments of OPEFB for Enzymatic Hydrolysis and Fermentation of Ethanol

The effect of pretreatment process from the combination of electron beam irradiation and alkaline to Oil Palm Empty Fruit Bunch (OPEFB) was studied. The combination of pretreatment method was considered as an alternative way to increase glucose yield. In this study, OPEFB was pretreated using Electron Beam Irradiation (EBI) at 100 kGy and 300 kGy and followed by chemical pretreatment. In chemical pretreatment, irradiated OPEFB was reacted with sodium hydroxide 6% and 10% in stirred vessel at 4 bars and 150 oC for 30 min. The effectiveness of pretreatment was evaluated by calculating the composition of chemical component using National Renewable Energy Laboratory (NREL) Method. The samples which were hydrolyzed using enzymes with the addition of 30 FPU of Cellic®CTec2 per gram of pretreated biomass resulted high glucose in the amount of 9.86%. The fermentation process using Saccharomyces cereviceae obtained the highest ethanol concentration for 5.36% at 72h. The combination of the two pretreatment methods gave an effect on the weight loss, chemical composition, structure, and enzymatic hydrolysis produc

Differences in angiographic profile and immediate outcome of primary percutaneous coronary intervention in otherwise risk-free young male smokers

Introduction: Cigarette smoking is a well-established risk factor for the development and progression of coronary artery disease (CAD) and it is strongly related to cardiac morbidity and mortality. Therefore, this study aimed to compare the angiographic profile and immediate clinical outcomes in young male smokers and non-smokers without any other cardiac risk factors presented with ST-elevation myocardial infarction (STEMI).Methods: This study includes young (≤40 years) male patients presented without cardiac risk factors other than smoking. Angiographic profile and immediate outcome of primary percutaneous coronary intervention (PCI) were collected from the hospital database.Results: A total of 580 young male patients were included in this study, 51.2% (297) were smokers. Baseline characteristics and presentation were similar for smoker and non-smoker groups. Angiographic profile was not significantly different for smokers in terms of pre-procedure thrombolysis in myocardial infarction (TIMI) flow (p = 0.373), the number of vessels involved (p = 0.813), infarct-related artery (p = 0.834), and left ventricular dysfunction (p = 0.311). Similarly, in-hospital outcomes of primary PCI were not significantly different in smokers. Post-procedure no-reflow was in 3.4% vs. 2.8%; p = 0.708, acute stent thrombosis in 1.7% vs. 0.4%; p = 0.114 and in-hospital mortality in 1.0% vs. 1.4%; p = 0.657 of the smoker and non-smoker group, respectively.Conclusion: Our study concludes smoking has no significant impact on the angiographic profile and immediate clinical outcomes of primary PCI after STEMI in young males, without any other conventional cardiac risk factors. With these findings, further multicenter prospective studies are needed to identify other potential causes in such patients

Field-free orientation of CO molecules by femtosecond two-color laser fields

We report the first experimental observation of non-adiabatic field-free orientation of a heteronuclear diatomic molecule (CO) induced by an intense two-color (800 and 400 nm) femtosecond laser field. We monitor orientation by measuring fragment ion angular distributions after Coulomb explosion with an 800 nm pulse. The orientation of the molecules is controlled by the relative phase of the two-color field. The results are compared to quantum mechanical rigid rotor calculations. The demonstrated method can be applied to study molecular frame dynamics under field-free conditions in conjunction with a variety of spectroscopy methods, such as high-harmonic generation, electron diffraction and molecular frame photoemission

Mapping MOS-HIV to HUI3 and EQ-5D-3L in Patients With HIV

Objectives: The Medical Outcomes Study HIV Health Survey (MOS-HIV) is frequently used in HIV clinical trials; however, scores generated from the MOS-HIV are not suited for cost-effectiveness analyses as they do not assign utility values to health states. Our objective was to estimate and externally validate several mapping algorithms to predict Health Utilities Index Mark 3 (HUI3) and EQ-5D-3L utility values from the MOS-HIV. Methods: We developed and validated mapping algorithms using data from two HIV clinical trials. Data from the first trial (n = 367) formed the estimation data set for the HUI3 (4,610 observations) and EQ-5D-3L (4,662 observations) mapping algorithms; data from the second trial (n = 168) formed the HUI3 (1,135 observations) and EQ-5D-3L (1,152 observations) external validation data set. We compared ordinary least squares (OLS) models of increasing complexity with the more flexible two-part, beta regression, and finite mixture models. We assessed model performance using mean absolute error (MAE) and mean squared error (MSE). Results: The OLS model that used MOS-HIV dimension scores along with squared terms gave the best HUI3 predictions (mean observed 0.84; mean predicted 0.80; MAE 0.0961); the finite mixture model gave the best EQ-5D-3L predictions (mean observed 0.90; mean predicted 0.88; MAE 0.0567). All models produced higher prediction errors at the lower end of the HUI3 and EQ-5D-3L score ranges

Loading capacity calculation of integrated precast slab and column panel using cold-formed steel

In the current study, the precast panel using a cold-formed steel section integrated with a cold-formed steel section integrated with self-compacting concrete was connected to the precast column panel. A T-shaped plate was used as a joint connector. Point loading applied onto the free-side of the slab panel. The material used to form a composite slab panel was C12524-type of cold-formed steel section as the reinforcements and it was integrated with self-compacting concrete. The connection in this research was divided into two-part. It was the side part and the middle part. The quality of cold-formed steel was fy = 530 MPa and fu = 590 MPa, the quality of the T-shaped plate connector grade was S355. The bolt diameter was variated with 10 mm, 12 mm, 14 mm, and 16 mm. The bolt quality was grade 8.8 (fy = 800 MPa). The calculation was the moment joint capacity of the connection and the stiffness. The moment joint capacity was increased within the bolt diameter increased. The side part of the specimen had the highest stiffness value; the bolts that could be used were M10, M12, and M14. To use the M16 bolt, configure the bolt spacing to be compatible with the standard BS EN 1-8:2005 [1]

Potential antimutagenic activity of berberine, a constituent of Mahonia aquifolium

BACKGROUND: As part of a study aimed at developing new pharmaceutical products from natural resources, the purpose of this research was twofold: (1) to fractionate crude extracts from the bark of Mahonia aquifolium and (2) to evaluate the strength of the antimutagenic activity of the separate components against one of the common direct-acting chemical mutagens. METHODS: The antimutagenic potency was evaluated against acridine orange (AO) by using Euglena gracilis as an eukaryotic test model, based on the ability of the test compound/fraction to prevent the mutagen-induced damage of chloroplast DNA. RESULTS: It was found that the antimutagenicity of the crude Mahonia extract resides in both bis-benzylisoquinoline (BBI) and protoberberine alkaloid fractions but only the protoberberine derivatives, jatrorrhizine and berberine, showed significant concentration-dependent inhibitory effect against the AO-induced chloroplast mutagenesis of E. gracilis. Especially berberine elicited, at a very low dose, remarkable suppression of the AO-induced mutagenicity, its antimutagenic potency being almost three orders of magnitude higher when compared to its close analogue, jatrorrhizine. Possible mechanisms of the antimutagenic action are discussed in terms of recent literature data. While the potent antimutagenic activity of the protoberberines most likely results from the inhibition of DNA topoisomerase I, the actual mechanism(s) for the BBI alkaloids is hard to be identified. CONCLUSIONS: Taken together, the results indicate that berberine possesses promising antimutagenic/anticarcinogenic potential that is worth to be investigated further