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The implementation of advanced multi-level modulation schemes such as quadrature phase-shift keying (QPSK) in contrast to the conventional on–off keying is crucial to further boost the terahertz (THz) communications speed. Thereby, carrier phase noise reduction in the THz range is one of the key goals that need to be urgently achieved. In this paper, the photonic-based THz sources and the phase noise problem are briefly summarized. Then, a low phase-noise photonic source based on the stimulated Brillouin scattering (SBS) optical fiber cavity is first applied for a 300-GHz-band QPSK wireless communication link. The highest data rate at forward-error-correction limited condition was 15 Gbaud utilizing the SBS-based photonic source with a small transmit power of ~ −36 dBm. Its transmission characteristics are evaluated and compared with the conventional optical frequency comb generator (OFCG)-based source at 5 Gbaud. The proposed SBS-based photonic source has been proven to offer better performances than the OFCG-based source with respect to the phase noise, optical carrier to noise ratio, and bit error rate in communications.
Atmospheric supply of iron (Fe) to the ocean has been suggested to regulate marine productivity in large parts of the world’s ocean. However, there are still large uncertainties regarding how the atmospheric inputs of dissolved Fe (DFe) influence the seawater DFe concentrations and thus net primary production (NPP). Here, we use an atmospheric chemistry model and two ocean biogeochemistry models with high (Model H) and low (Model L) sensitivities to atmospheric sources of DFe to explore the responses of ocean biogeochemistry to different types of atmospheric inputs of DFe: mineral dust and combustion aerosols. When both Fe content in mineral dust of 3.5% and Fe solubility of 2% are prescribed in sensitivity simulations, the ocean models overestimate DFe concentration in the surface ocean downwind from the North African and East Asian dust plumes. Considering different degrees of atmospheric Fe processing reduces the overestimates of DFe concentration in the North Atlantic and North Pacific. The two ocean biogeochemistry models show substantially different magnitudes of responses to the atmospheric input of DFe. The more detailed Model H shows a much higher sensitivity of NPP to the change in combustion aerosols than to mineral dust, regardless of relative inputs of the sedimentary sources. This finding suggests that pyrogenic Fe-containing aerosols are more important sources of atmospheric bioavailable Fe for marine productivity than would be expected from the small amount of DFe deposition, especially in the Pacific and Southern oceans.
It is thought that protoplanets formed in protoplanetary disks excite the orbital motion of the surrounding planetesimals, and the bow shocks caused by the highly excited planetesimals heat their icy component evaporating into gas. We have performed model calculations to study the evolution of molecular abundances of the evaporated icy component, which suggests sulfur-bearing molecules can be good tracers of icy planetesimal evaporation. Here we report the result of our ALMA observations of sulfur-bearing molecules towards protoplanetary disks. The lines were undetected but the obtained upper limits of the line fluxes and our model calculations give upper limits of the fractional abundances of x(H2S) < 10−11 and x(SO) < 10−10 in the outer disk. These results are consistent with the molecular abundances in comets in our Solar system.
Microcavity exciton-polaritons are interacting Bose particles which are confined in a two-dimensional (2D) system suitable for studying coherence properties in an inherently nonequilibrium condition. A primary question of interest here is whether a true long-range order exists among the 2D exciton-polaritons in a driven open system. We give an overview of theoretical and experimental works concerning this question, and we summarize the current understanding of coherence properties in the context of Berezinskii-Kosterlitz-Thouless transition.
Strange but striking phenomena, which are accessed by advanced experimental techniques, become a fuel to stimulate both experimental and theoretical research. Experimentalists concoct new tools for sophisticated measurements, and theorists establish models in order to explain the surprising observation, ultimately expanding our knowledge boundary. A classic example of the seed to the knowledge expansion is the feature of abnormally high heat conductivity in liquid helium reported by Kapitza and Allen's group, who used cryogenic liquefaction techniques in 1938 [1, 2]. It is a precursor to a “resistance-less flow” a new phase of matter, coined as superfluidity in the He-II phase. Immediately after this discovery, London conceived a brilliant insight between superfluidity and Bose-Einstein condensation (BEC) of noninteracting ideal Bose gases , which has led to establish the concept of coherence as off-diagonal long-range order emerging in the exotic states of matter. Since then, it is one of the core themes in equilibrium Bose systems to elucidate the intimate link of superfluidity and BEC in natural and artificial materials, where dimensionality and interaction play a crucial role in determining the system phase.
Let us consider the noninteracting ideal Bose gases whose particle number N is fixed in a three-dimensional box with a volume V. According to the Bose-Einstein statistics, the average occupation number Ni in the state i with energy is given by with the chemical potential and a temperature parameter (Boltzmann constant kB and temperature T). For the positive real number of is restricted to be smaller than, and the ground-state particle number N0 diverges as approaches the lowest energy. Its thermodynamic phase transition refers to BEC, in which the macroscopic occupation in the ground state is represented by the classical field operator, where is the particle density and is the phase.
Insufficient nutrition during the perinatal period causes structural alterations in humans and experimental animals, leading to increased vulnerability to diseases in later life. Japanese quail, Coturnix japonica, in which partial (8–10%) egg white was withdrawn (EwW) from eggs before incubation had lower birth weights than controls (CTs). EwW birds also had reduced hatching rates, smaller glomeruli and lower embryo weight. In EwW embryos, the surface condensate area containing mesenchymal cells was larger, suggesting that delayed but active nephrogenesis takes place. In mature EwW quail, the number of glomeruli in the cortical region (mm2) was significantly lower (CT 34.7±1.4, EwW 21.0±1.2); capillary loops showed focal ballooning, and mesangial areas were distinctly expanded. Immunoreactive cell junction proteins, N-cadherin and podocin, and slit diaphragms were clearly seen. With aging, the mesangial area and glomerular size continued to increase and were significantly larger in EwW quail, suggesting compensatory hypertrophy. Furthermore, apoptosis measured by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling analysis was higher in EwWs than in CTs on embryonic day 15 and postnatal day 4 (D4). Similarly, plasma glucocorticoid (corticosterone) was higher (P<0.01) on D4 in EwW quail. These results suggest that although nephrogenic activity is high in low-nutrition quail during the perinatal period, delayed development and increased apoptosis may result in a lower number of mature nephrons. Damaged or incompletely mature mesangium may trigger glomerular injury, leading in later life to nephrosclerosis. The present study shows that birds serve as a model for ‘fetal programming,’ which appears to have evolved phylogenetically early.
To verify the effectiveness and safety of the addition of adipose-derived regenerative cells to autologous fat injection therapy.
Unilateral vocal fold paralysis models were made by cutting the right recurrent laryngeal nerve in two pigs. At day 30, 0.5 ml adipose-derived regenerative cells mixed with 1 ml autologous fat was injected into the right vocal fold of one pig, with the other receiving 0.5 ml Ringer's solution mixed with 1 ml autologous fat. At day 120, fibrescopy, laser Doppler flowmeter, computed tomography, vocal function evaluation and histological assessment were conducted.
Although histological assessment revealed atrophy of the thyroarytenoid muscle fibre in both pigs, there was remarkable hypertrophy of the thyroarytenoid muscle fibre in the area surrounding the adipose-derived regenerative cells injection site.
The addition of a high concentration of adipose-derived regenerative cells to autologous fat injection therapy has the potential to improve the treatment outcome for unilateral vocal fold paralysis.
Stabilized Au NPs were directly deposited on nanostructured ZnO and ZrO2 by a simple one-step strategy based on sacrificial anode electrolysis. The annealed nanocomposites are proposed as active layers in resistive gas sensors for low-cost processes. Results on the performance of gas sensors based on pristine and Au-doped MOx nanostructured thin films, used for the detection of NO2 gas, were reported at an operating temperature of 300°C, evaluating the effects of the MOx chemical composition and morphology, and the Au-doping.
We report the investigation of ZnO thin films delta-doped with lithium and phosphorus introduced simultaneously. The films were deposited from high purity ceramic targets of ZnO and Li3PO4 on c-plane sapphire substrates by RF magnetron sputtering. An undoped ZnO film with a low background electron concentration was used as the buffer layer on the sapphire substrate. The doped films were prepared by carrying simultaneous sputtering from the ZnO and Li3PO4 ceramic targets. For uniform doped films, the simultaneous deposition from the ZnO and Li3PO4 was uninterrupted. For the delta-doped films on the other hand, deposition from the ZnO target was uninterrupted while that from the Li3PO4 was interrupted periodically using a shutter. Post-deposition annealing was carried using a rapid thermal processor in O2 at 900 oC for 3 min. Results obtained from photoluminescence spectroscopy measurements at 12 K revealed acceptor-related luminescence peaks at 3.35 eV, possibly due to the transition from exciton bound to a neutral acceptor. The x-ray diffraction 2θ-scans showed a single peak at about 34.4o. Hall effect measurements revealed p-type conductivities with an average Hall concentrations of 3.8 x 1013 cm-3 in uniform doped samples and 1.5 x 1016 cm-3 in delta doped samples. However, in some cases the Hall coefficients had both positive and negative values, making the determination of the carrier type inconclusive. The fluctuation in the carrier type could be due to the lateral inhomogeneity in the hole concentration caused by signal noise impacting the small Hall voltages in the measurements.
Sustained friction drag reduction and heat transfer augmentation are simultaneously achieved in a fully developed channel flow where the averaged transport equations and wall boundary conditions for momentum and heat have identical form. Zero-net-mass-flux wall blowing and suction is assumed as a control input and its spatio-temporal distribution is determined based on optimal control theory. When the root-mean-square value of the control input is 5 % of the bulk mean velocity, the friction drag is decreased by 24 % from the uncontrolled value, whereas the heat transfer is more than doubled. Optimizations with different amplitudes of the control input and different Reynolds numbers reveal that the optimal control inputs commonly exhibit the property of a downstream travelling wave, whose wavelength is ∼250 in wall units and phase velocity is ∼30 % of the bulk mean velocity. Detailed analyses of the controlled velocity and thermal fields show that the travelling wave input contributes to dissimilar heat transfer enhancement through two distinct mechanisms, i.e. direct modification of the coherent velocity and thermal fields and an indirect effect on the random fields. The present results show that the divergence-free velocity vector and the conservative scalar are essentially different, and this is a key to achieving dissimilar heat transfer enhancement in turbulent shear flows.
A human immunodeficiency virus-1 (HIV-1)-positive male undergoing antiretroviral therapy was diagnosed with an axillary lymph node abscess caused by Corynebacterium ulcerans, and an environmental survey revealed that the patient's cat as the source of infection.
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.
Altered levels of phenylalanine and its metabolites in blood and cerebrospinal fluid have previously been reported in schizophrenia. This study attempted to examine whether phenylalanine kinetics is altered in schizophrenia using the 13C-phenylalanine breath test (13C-PBT).
Subjects were 20 patients with schizophrenia and the same number of controls. 13C-phenylalanine was administered and then 13CO2 concentration in breath was monitored for 120 minutes. The Δ 13CO2 at each collecting time, the maximal Δ 13CO2 (Cmax), the time to reach Cmax (Tmax), the area under the curve of time course of Δ13CO2 (AUC), the cumulative recovery rate (CRR) at each collecting time of the 13C-PBT were calculated for each subject.
Body weight (BW) and diagnostic status were significant predictors for Cmax. BW, age and diagnostic status were significant predictors for AUC and CRR at 120 minutes (CRR0-120). A repeated measures ANCOVA controlling for age and BW revealed a different pattern of change in CRR over time between the patients and controls and that Δ13CO2 in schizophrenia were lower than that in healthy control at all sampling point during 120 min, with an overall significant differences between healthy control and schizophrenia. The ANCOVA controlling for age and BW, showed that Cmax, AUC and CRR0-120 were significantly lower in schizophrenics than in controls.
Our data indicate the different change of Δ13CO2 and CRR over time and the decreased Cmax, AUC and CRR0-120 of 13C-PBT in schizophrenia patients compared to healthy controls, suggesting the altered phenylalanine kinetics in schizophrenia.
This study examined the crystallization of vanadate glasses by using microwave irradiation. A second aim was comparing the thermoelectric properties of crystallized glasses when using microwave irradiation to conventional heating. V2O5-P2O5-Fe2O3-CuO glasses were prepared by using the melt quenching method. These glasses were irradiated by 2.45-GHz microwaves and heated in an electric furnace. MxV2O5 (M= Cu, Fe x=0.26-055) crystals were selectively precipitated by using the microwave irradiation. The crystal growth was also promoted by it. As a result, precipitation crystals formed a fiber-like structure. The electrical conductivity of the microwave irradiated glass was 6.3×101S/m at room temperature, which was three times higher than the value of conventionally-heated glass. The Seebeck coefficient of the microwave irradiated glass was -127 μV/K at room temperature, which was two times higher than that of conventionally-heated glass. This caused the power factor to be improved about 12 times. These results show that microwave irradiation is a potential candidate for obtaining conductive crystallized vanadate glasses.
We have investigated the effect of temperature annealing on bilayer heterojunction solar cells based on poly[9,9’-hexyl-fluorene-alt-bithiophene] as active layer. Film morphology for different temperature annealing was probed by atomic force microscopy (AFM) and the values of roughness range from 0.59 up to 2.15 nm. The best photovoltaic performance was found for devices with active layer annealed at 200°C with power conversion efficiency (η) of 2.8 % while devices without annealing presented only 0.4%. This performance enhancement is attributed to the reduction of traps and increased hole mobility after the thermal annealing.
The LaFeO3 and CaFeOX layers are grown using highly dense target prepared by Pechini method, with which accurate growth rate is achieved. Since the LaFeO3demonstrates the obvious RHEED oscillation until the end of growth, constant growth rate, and the step-terraces structure, the LFO is employed as a buffer and/or reference layer to determine the required pulses to deposit the thickness we desire in the superlattice. Superlattices show the clear satellite peaks and Laue oscillation in the XRD spectra as well as the oscillations caused by the film thickness with a flat surface and superstructure with a flat interface in the x-ray reflection spectrum. The streaky RHEED patterns and step-terraces surface are consistent with the results of spectra using x-ray.