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The wings of butterflies are relatively heavier than those of other insects, and the inertial force and torque due to the wing mass are likely to have a significant effect on agility and manoeuvrability in the flapping flight of butterflies. In the present study, the effect of wing mass on the free flight of butterflies is investigated by numerical simulations based on an immersed boundary–lattice Boltzmann method. We use a butterfly-like model consisting of two square wings with mass connected by a rod-shaped body. We simulate the free flights of the model by changing the ratio of the wing mass to the total mass of the model and also changing the mass distributions of the wings. As a result, we find that the aerodynamic vertical and horizontal forces decrease as the wing-mass ratio increases, since for a large wing-mass ratio the body has large vertical and horizontal oscillations in each stroke and consequently the speeds of the wing tip and the leading edge relatively decrease. In addition, we find that the wing-mass ratio has a dominant effect on the rotational motion of the model, and a large wing-mass ratio reduces aerodynamic force and intensifies the time variation of the pitching angle. From the results of our free flight simulations, we clarify the critical wing-mass ratio between upward flight and downward flight and find that the critical wing-mass ratio is a function of the non-dimensional total mass and almost independent of the wing length. Then, we evaluate the effect of the wing-mass distribution on the critical wing-mass ratio. Finally, we discuss the limitations of the model.
MXenes are a novel class of two dimensional materials, discovered by Barsoum and Gogotsi [M. Naguib, J. Come, B. Dyatkin, V. Presser, P. Taberna, P. Simon, M. W. Barsoum, and Y. Gogotsi, Electrochemistry Communications 16, 61-64 (2012); B. Anasori, M. R. Lukatskaya, and Y. Gogotsi, Nature Reviews Materials vol. 2, 16098 (2017)]. Their large specific surface area and the tunability of their physicochemical properties as a function of the transition metal and surface terminal group make them a unique design platform for various applications, a primary example of which is pseudocapacitive energy storage. However, there is still incomplete understanding of how the transition metal chemistry and stoichiometry, and the surface termination affect charge storage mechanisms in MXene. In this study, we have performed systematic first-principles calculations for bulk MXene and found that the atomic charge of the metal cations, which is related to their valence, decreases across the d-electron metal series. Electronic-structure indicators of performance are examined to understand the energy storage behavior, whereby charges are stored between the terminal groups and adsorbing cations. Importantly, we found that the differential Bader charges show good agreement with theoretical capacitances and are useful in predicting charge storage trends in MXene-based pseudocapacitors. Furthermore, we have performed first-principles and grand canonical Monte Carlo calculations for the slab systems, finding that the solvent plays a critical role in enhancing the pseudocapacitive response.
Tuberculosis (TB) remains an important problem among end-stage renal disease (ESRD) patients. We reviewed the epidemiology of TB and ESRD, investigations of TB exposures in US dialysis facilities, and published guidelines to inform screening and treatment practices among US ESRD patients. Compared to TB in the general population, ESRD patients have 6–25-fold higher TB incidence rates, and mortality during treatment is 2–3-fold higher. Most TB cases among ESRD patients (~90%) occur among non–US-born persons, and an analysis of genotyping data suggests that 80% of all cases result from latent TB infection (LTBI) reactivation. Published TB contact investigations in dialysis facilities have reported cases among ESRD patients and healthcare workers. However, transmission of TB is rare: there were no reports of secondary cases of TB because of exposure to an index-case patient and there were few TB infections, which was demonstrated by low occurrence of newly positive tuberculin skin tests (12%–16%) and conversions (8%–17%) among contacts. Targeted TB education, screening, and treatment for ESRD patients at highest risk for TB exposure (eg, non–US-born persons), using interferon-gamma release assays and short course LTBI regimens (ie, isoniazid-rifapentine weekly for 12 weeks or rifampin daily for 4 months) may be an effective overall strategy for reducing TB burden in ESRD patients.
Cognitive–behavioral therapy (CBT) is thought to be useful for chronic pain, with the pathology of the latter being closely associated with cognitive–emotional components. However, there are few resting-state functional magnetic resonance imaging (R-fMRI) studies. We used the independent component analysis method to examine neural changes after CBT and to assess whether brain regions predict treatment response.
We performed R-fMRI on a group of 29 chronic pain (somatoform pain disorder) patients and 30 age-matched healthy controls (T1). Patients were enrolled in a weekly 12-session group CBT (T2). We assessed selected regions of interest that exhibited differences in intrinsic connectivity network (ICN) connectivity strength between the patients and controls at T1, and compared T1 and T2. We also examined the correlations between treatment effects and rs-fMRI data.
Abnormal ICN connectivity of the orbitofrontal cortex (OFC) and inferior parietal lobule within the dorsal attention network (DAN) and of the paracentral lobule within the sensorimotor network in patients with chronic pain normalized after CBT. Higher ICN connectivity strength in the OFC indicated greater improvements in pain intensity. Furthermore, ICN connectivity strength in the dorsal posterior cingulate cortex (PCC) within the DAN at T1 was negatively correlated with CBT-related clinical improvements.
We conclude that the OFC is crucial for CBT-related improvement of pain intensity, and that the dorsal PCC activation at pretreatment also plays an important role in improvement of clinical symptoms via CBT.
It has been demonstrated that negatively distorted self-referential processing, in which individuals evaluate one's own self, is a pathogenic mechanism in subthreshold depression that has a considerable impact on the quality of life and carries an elevated risk of developing major depression. Behavioural activation (BA) is an effective intervention for depression, including subthreshold depression. However, brain mechanisms underlying BA are not fully understood. We sought to examine the effect of BA on neural activation during other perspective self-referential processing in subthreshold depression.
A total of 56 subjects underwent functional magnetic resonance imaging scans during a self-referential task with two viewpoints (self/other) and two emotional valences (positive/negative) on two occasions. Between scans, while the intervention group (n = 27) received BA therapy, the control group (n = 29) did not.
The intervention group showed improvement in depressive symptoms, increased activation in the dorsal medial prefrontal cortex (dmPFC), and increased reaction times during other perspective self-referential processing for positive words after the intervention. Also, there was a positive correlation between increased activation in the dmPFC and improvement of depressive symptoms. Additionally, there was a positive correlation between improvement of depressive symptoms and increased reaction times.
BA increased dmPFC activation during other perspective self-referential processing with improvement of depressive symptoms and increased reaction times which were associated with improvement of self-monitoring function. Our results suggest that BA improved depressive symptoms and objective monitoring function for subthreshold depression.
We report here the fabrication and characterization of GaAs tunnel diode (TD) and ErAs nanoparticles (Nps) enhanced GaAs TD. Four GaAs TDs with different contact area were fabricated by using MOCVD. We found extremely high peak current density of ∼250A/cm2 for the TD with r=0.25mm contact area. Moreover a hysteresis loop was appeared during sweeping up and sweeping down the external voltage. A ‘vector load line model’ was proposed to explain the origin of the shape of the hysteresis loop and the onset of the bistability occurred at the intersect of the loadline and the current-voltage (I-V) curve of TD. Meanwhile, we have grown ErAs Nps on GaAs(100) surface by using MBE and succeeded in overgrowth of GaAs after ErAs deposition. GaAs(p+)/ErAs(Nps)/GaAs(n+) TDs were fabricated and characterized. We found the GaAs sample containing 70s deposition of ErAs showed the best TD behavior. No TD behavior was observed for the sample without addition of ErAs Nps, clearly indicating the strong tunneling enhancement effect from ErAs Nps.
Low birth weight was associated with cardiometabolic diseases in adult age. Insulin-like growth factor-1 (IGF-1) has a crucial role in fetal growth and also associates with cardiometabolic risks in adults. Therefore, we elucidated the association between IGF-1 level and serum lipids in cord blood of preterm infants. The subjects were 41 consecutive, healthy preterm neonates (27 male, 14 female) born at <37-week gestational age, including 10 small for gestational age (SGA) infants (<10th percentile). IGF-1 levels and serum lipids were measured in cord blood, and high-density lipoprotein cholesterol (HDLC), low-density lipoprotein cholesterol (LDLC) and very low-density lipoprotein triglyceride (VLDLTG) levels were determined by HPLC method. SGA infants had lower IGF-1 (13.1 ± 5.3 ng/ml), total cholesterol (TC) (55.0 ± 14.8), LDLC (21.6 ± 8.3) and HDLC (26.3 ± 11.3) levels, and higher VLDLTG levels (19.0 ± 12.7 mg/dl) than in appropriate for gestational age (AGA) infants (53.6 ± 25.6, 83.4 ± 18.9, 36.6 ± 11.1, 38.5 ± 11.6, 8.1 ± 7.0, respectively). In simple regression analyses, log IGF-1 correlated positively with birth weight (r = 0.721, P < 0.001), TC (r = 0.636, P < 0.001), LDLC (r = 0.453, P = 0.006), and HDLC levels (r = 0.648, P < 0.001), and negatively with log TG (r = −0.484, P = 0.002) and log VLDL-TG (r = −0.393, P = 0.018). Multiple regression analyses demonstrated that IGF-1 was an independent predictor of TC, HDLC and TG levels after the gestational age and birth weight were taken into account. In preterm SGA infants, cord blood lipids profile altered with the concomitant decrease in IGF-1 level.
To increase X-ray photon number generated by laser-cluster interaction, it is important to understand the dependence of X-ray generation on cluster size. We carried out Xe K-shell X-ray generation using a conical nozzle with Xe clusters, the radius of which was controllable by adjusting the backing pressure. The experiment clarifies the result that the Xe K-shell X-ray photon number increases with increasing cluster radius from 8 to 12 nm, and saturates at the radius between 12 and 17 nm. We also investigated the Xe K-shell X-ray photon number dependence on laser intensity, and found that the threshold laser intensity of the Xe K-shell X-ray generation exists between 2 × 1017 and 5 × 1018 W/cm2.
The near-infrared (NIR) spectral range (2–5 μm) contains a number of interesting features for the study of the interstellar medium. In particular, the aromatic and aliphatic components in carbonaceous dust can be investigated most efficiently with the NIR spectroscopy. We analyze NIR spectra of the diffuse Galactic emission taken with the Infrared Camera onboard AKARI and find that the aliphatic to aromatic emission band ratio decreases toward the ionized gas, which suggests processing of the band carriers in the ionized region.
Lasing characteristics of a single Zinc oxide (ZnO) nanosheet and a single ZnO nanowire were investigated by an ultraviolet light excitation. ZnO nanocrystals were synthesized by chemical vapor deposition (CVD) method, and those ZnO nanocrystals were excited by a third-harmonic Q-switched Nd:YAG laser beam (355 nm, 5 ns). The emission spectra from a single ZnO nanocrystal was collected by an objective lens with a magnification factor of 100 or 50, coupled with a spectrometer with a light fiber. The area observed by the spectrometer is about 10 μm in diameter, and therefore the emission spectra from a single ZnO nanocrystal can be observed. The emission spectra showed the obvious lasing characteristics having mode structure and a threshold for lasing. The lasing threshold power density of a ZnO nanosheet and a ZnO nanowire were measured to be about 60 kW/cm2 and 150 kW/cm2, respectively. ZnO nanosheet can be a superior laser medium due to the lower threshold for lasing compared to the threshold of the ZnO nanowire. However, since the lasing spectra had mode structure, a single-longitudinal mode lasing would be required for a practical application. The single longitudinal mode lasing can be realized by a nanomachining of a grating on the ZnO nanocrystal surface due to distributed bragg reflector (DBR) laser. The minimum DBR pitch was estimated to be about 81 nm, which can be machined by focused-ion beam (FIB) focused up to 7 nm at minimum, and therefore, we demonstrated the nanomachining on a single ZnO nanowire. However, the single-longitudinal mode lasing was not observed so far, and thus optimization of experimental conditions such as the DBR pitch, ion dose amount and increasing the number of repetition of DBR would be required.
Within the Herschel key project “The Warm And Dense ISM” (WADI) we systematically observe
a number of prominent photon-dominated regions (PDRs) to measure the impact of varying UV
fields on the energy balance, the chemical and dynamical structure of heated molecular
We report the analysis of the mid-infrared spectral maps observed by Spitzer/IRS toward star-forming regions where the Herschel key program WADI has observed / will observe with HIFI and PACS. The IRS spectra are fitted using 4 components of small grains: PAH0, PAH+, PAHx, and evaporating VSG, and the spatial distributions of these components are derived.
Mg1-zCaz (0.03 < z < 0.17) alloy thin films covered with thin Pd are hydrogenated using 4% H2 in Ar under atmospheric pressure at room temperature. The optical indices, which are refractive indices and extinction coefficients, in the wavelength between 250 and 1700 nm of these hydrides were evaluated with spectroscopic ellipsometry. The evaluated refractive indices were about 2.0 for all hydrides, while the extinction coefficients showed the values less than 0.06 in the visible range for hydride with Ca composition of z ≤ 0.08 and the coefficients increased sharply to more than 0.3 with Ca composition z > 0.08.
Near-infrared (NIR; 2.5–5 μm) low-resolution
(λ/Δλ ~ 100) spectra were obtained for a
number of Galactic and extragalactic objects with the Infrared Camera (IRC) in the AKARI
warm mission. These data provide us with the first opportunity to make a systematic study
of the 3.3–3.5 μm PAH features in a galactic scale as well as within an
object. Whereas the 3.3 μm band is well resolved in most spectra, the
3.5 μm band is not clearly separated from the 3.4 μm
band in the IRC spectrum. The intensity ratio of the summation of the 3.4 and
3.5 μm bands to the 3.3 μm band shows a tendency to
increase towards the Galactic center, although a large variation in the ratio is also seen
in a local scale. A search for deuterated PAH features in the 4 μm region
is carried out in IRC NIR spectra. Emission lines originating from the ionized gas
together with the detector anomaly hamper an accurate search at certain wavelengths, but
little convincing evidence has so far been obtained for the presence of significant
features in 4.2–4.7 μm. A conservative upper limit of a few percents is
obtained for the integrated intensity ratio of the 4.4–4.7 μm possible
features to the 3.3–3.5 μm PAH features in the spectra so far
Leachabilities and solubilities of the synthesized iodide sodalite and natural (chloride) sodalite were measured by leach test. The iodide sodalite was synthesized in nitrogen gas flow at 800°C for 2 hours. The crystalline structure of the product was certified by XRD analysis. The natural sodalite containing chlorine was obtained at Bancroft, Canada. The several types of solution were used to evaluate the influence of the solubility of sodalite that included the varied pH and the chemical compositions. The solubilities of chloride sodalite were calculated by the thermodynamics data. The solubility measured for the synthesized iodide sodalite was compared with that calculated. The solubility of the synthesized iodide sodalite was approximately 2 x 10-4 mol/L, which shows a good agreement with the calculated one of the natural sodalite.
Electrical characteristics of Spindt-type Molybdenum (Mo) field emitter triode devices with varied emitter tip-height have been studied based on device modeling and experiment. Potential and electric field distributions with varied the emitter tip-height has been simulated. It is observed that the electric field of the top of the higher emitter tip was strongly affected with the anode-gate distance and the anode voltage compared to conventional field emitter triode device. Experimental results with varied different tip-height were in good agreement with that of calculated results. We present the possibility of “depletion mode” field emitter triode device.
The existence of effective pinning in single T1-layer 1223 superconductors has been reported [1–3], as opposed to lower values in T1- and Bi-double layer systems, which is intimately related to their crystal structures. In order to investigate the possibility of T1–1223 being applied as a practical superconductor, tape shaped wires of the chemical composition (T10.5Pb0.51 (Sr0.8Ba0.2Ca2Cu3O9were prepared. Transport Jc of T1–1223 was measured to be 1.8 × 104 A/cm2 at 77K in the absence of a magnetic field. These results seem to imply that T1–1223 has, not only effective pinning because of having a more 3-dimensional vortex line lattice like YBa2Cu3O7, but also better grain boundary weak-link performance than YBa2Cu3O7. PresenT1y it appears that T1–1223 may be a superior choice to make better superconducting wire, because of these considerations and of the higher Tc of 120K.
(T10.5Pb0.5)1Sr2CaCu2O7 (T1–1212) also seems to have effective pinning, as well as T1–1223, supporting the idea that shorter Cu-O plane spacing, or absence of thicker insulating region such as T12O2 or Bi2O2 double layer, are beneficial for effective pinning through facilitating a better 3D-like vortex line lattice [4, 5]. Our “1212” and “1223” samples are good counter examples to the 2D pancake-like vortex theory [6, 7].