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Background p-Coumaric acid (pCA) is an essential bioactive compound for nutraceutical and pharmaceutical purposes; however, high-level pCA biosynthesis via in vivo is challenging due to the complexity of pathways and genetic designs. Hence, to produce pCA in a one-step reaction, it is crucial to establish whole-cell (WC) biocatalyst of recombinant tyrosine ammonia lyase (EC 4.3.1.23) with high activity, stability, and robustness properties. Methods Three different tyrosine ammonia lyase (TAL) genes were cloned and overexpressed under T7 promoter in Escherichia coli BL21(DE3). First, a copy GroELS was integrated in E. coli chromosome using a phage attack approach while rare codons and fusion TrxA-tag were cloned in a plasmid with the best TAL (Rhodotorula toluroides; RtTAL) for pCA production. Further optimization was conducted to the effect of temperature, medium, inducer, and metal ions, as well as biotransformation parameters. Significant findings Optimal pCA biotransformation was first explored using recombinant RtTAL in a low-cost medium with glycerol and lactose. Integrating a single copy of GroELS in E. coli chromosome and inserting the TrxA-tag, p32a-RtTAL/BD::7G, exhibited markedly elevated specific enzymatic activity of 16.14 μM mg−1 min−1 and conversion up to 94.8%. Moreover, RtTAL showed a 50% increase in the presence Mn2+ metal ions, while the whole-cell biocatalyst converted tyrosine to high-level of pCA up to 2.1 g/L by summation of 5-repeated batch reaction.

Electric currents in condensed-matter systems driven by the intense laser fields are opening new frontiers in petahertz electronics. However, new challenges are arising as the role of band structure in solid-state high-order harmonic generation (SHHG) has yet to be resolved. Here, we adopt a derivative-free unconstrained optimization algorithm to optimize the band structure for the SHHG, and investigate the sensitivity of the SHHG to the band structure of the solid by using a single-band model. We find that the band structure play an important role in SHHG.

We present an ab initio precision investigation of the subtle details of the spectral and temporal fine structures of high-order harmonic generation (HHG) in laser-driven electron-rescattering by using a new synchrosqueezing transform method (SST). The SST time-frequency analysis allows us to explore the in depth dynamics and contributions of the quantum trajectories in HHG associated with the electron-rescattering. Particularly it uncovers the subtle details of the spectral and temporal fine structures of the HHG and provides novel insights regarding the dynamical origin of the HHG in below-threshold harmonic regimes.

We present an ab initio study of quantitative extraction of the time–frequency spectra of multiple rescattering processes of the electrons driven by the mid-infrared laser field in a high-order har...

Efficient biological carbon dioxide sequestration for slowing down the climate changes requires a highly active and stable carbonic anhydrase (CA). A CA from Mesorhizobium loti (i.e., MlCA) was first over-expressed in E. coli via different vectors and a concentration of up to 5 g/L was obtained with pET32a(+). The whole cell biocatalyst was stable between pH 4.0 and pH 9.0 and maintained 82% activity within 6% salinity. The cations NH4+, K+, Na+, Mg2+, Ca2+ and Mn2+ did not affect the catalytic activity, while Co2+, Cu2+, and Zn2+ inhibited >70% biocatalyst activity at 5 mM. The Kcat and Km of whole cell CA was observed to be 1.76 × 106 /s and 0.0133 mM, while that of the crude enzyme was of 2.35 × 106 s−1 and 0.0364 mM, respectively. The effective diffusivity coefficient (De) of whole cell CA was 3.98 μ m2/s. Whole cell biocatalyst immobilized in 2% (w/v) agar could be reused for 6 times for CO2 sequestration and remained stable for 40 days. A novel two-column system with immobilized whole cell biocatalyst and recombinant MlCA effectively converted 100% CO2 to CaCO3 within 3.5 min. This provides an alternative, eco-friendly and low-cost process for carbon capture and storage (CCS) in the future.

It has been widely reported that the serum anion gap is significantly associated with mortality in intensive care unit (ICU); however, it remains unknown whether the association is present in aortic aneurysm (AA) patients. The present study aimed to investigate the association between the admission serum anion gap and ICU mortality in AA patients. Data extracted from a publicly accessible clinical database using a modifiable data mining technique were analyzed retrospectively, mainly by employing multivariable logistic regression analysis. The primary study outcome was ICU mortality. A total of 273 patient records were analyzed. The ICU mortality was 8.79% (24/273). The median serum anion gap was significantly higher in non-survivors [17.50 mEq/l, interquartile range (IQR) 15.75-22.50 mEq/l] compared with survivors [13.00 mEq/l, IQR 11.00-15.00 mEq/l, P

Background Shewanella genus is famous for applications like electron transfer in microbe fuel cells and bioremediation of heavy metals through the Mtr pathway. A potential way to enhance the electron genesis ability of Shewanella is to express exogenous mtr genes via recombinant DNA technology. Thus, to design and develop expression vectors capable of replicating in Shewanella and enhance the genetic toolbox of the same is important. Result In this study, a plasmid construct with a replication origin, repB, and pLacI promoter is reported for the first time to drive the expression of green fluorescent protein in S. oneidensis MR-1. Based on the same vector, the Mtr pathway genes mtrA, mtrC, and mtrCAB were also successfully expressed in MR-1. The recombinant strains had higher ferric reductase activity compared to the wild type. The highest enzymatic activity of 508.33 U/L in genetic Shewanella with mtrC gene is obtained, which is 1.53-fold higher than that of wild strain. The plasmids were stable up to 90 generations. Conclusion We have demonstrated an expression system based on pLacI promoter and repB ori in Shewanella. Consequently, the combination of repB and pLacI will have great potential in Shewanella to turn on expression of different genes constitutively.

We propose an efficient method for the enhancement of below-threshold harmonic generation (BTHG) by mid-infrared laser-driven excited states of a Cs atom. The BTHG is calculated by solving three-dimensional time-dependent Schrodinger equation accurately and efficiently using the time-dependent generalized pseudospectral method. We adopt an excited state as the initial state of a Cs atom. As a result, the BTHG is significantly enhanced by two orders of magnitude compared with the case of the initial ground state. Furthermore, we find that a single vacuum-ultraviolet pulse can be generated by mid-infrared laser-driven excited states by superposing several below-threshold harmonics of a Cs atom. Our finding suggests that the generation of below-threshold harmonics by laser-driven excited states of an atom can provide a powerful methodology for the production of intense vacuum-ultraviolet pulses.

We present ab initio simulations of optimal control of high-order-harmonic generation spectra that enable the synthesis of a circularly polarized 53-attosecond pulse in a single Helium atom response. The Bayesian optimization is used to achieve control of a two-color polarization gating laser waveform such that a series of harmonics in the plateau region are phase-matched, which can be used for attosecond pulse synthesis. To find the underlying mechanisms for generating these harmonics, we perform a wavelet analysis for the induced dipole moment in acceleration form, and compare the time-energy representation with the quantum paths extracted from the semiclassical calculation. We found that these coherent harmonics are excited along the short trajectories. The proposed method has the potential to migrate to laboratories for generation of isolated circularly polarized ultrashort attosecond pulses.

Recently, studies of high-order harmonic generation (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields have received considerable attention for this process could be a potential source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup. In this paper, we address the problem with molecular targets and perform a detailed quantum study of the ${\mathrm{H}}_{2}{}^{+}$ molecule in bichromatic (${\ensuremath{\omega}}_{0}, 2{\ensuremath{\omega}}_{0}$) counter-rotating circular polarized laser fields where we adopt wavelengths (790 and 395 nm) and intensities ($2\ifmmode\times\else\texttimes\fi{}{10}^{14}\phantom{\rule{0.28em}{0ex}}\mathrm{W}/{\mathrm{cm}}^{2}$) reported in a recent experiment [K. M. Dorney et al., Phys. Rev. Lett. 119, 063201 (2017)]. Here, we demonstrate appropriate conditions to produce perfectly circular polarized harmonics. The calculated radiation spectrum contains doublets of left and right circularly polarized harmonics which display perfect circular polarization with use of the trapezoidal pulse shape, and substantial deviations from perfect circular polarization with use of the sine-squared pulse shape. We also study in detail short- and long-cycle counter-rotating circularly polarized driving pulses with a time delay between the two driving fields, ${\ensuremath{\omega}}_{0}$ and $2{\ensuremath{\omega}}_{0}$. These time delayed circularly polarized driving pulses are applied to H atoms and ${\mathrm{H}}_{2}{}^{+}$ molecules, and in both atomic and molecular cases we conclude a zero time delay corresponds to the highest HHG intensity for short pulses. For longer pulses there are no distinct differences in HHG intensities between the zero and nonzero time delays if the latter are within a few optical cycles of the fundamental frequency.

We demonstrate the ability to control the electron recollisions giving three returns per one cycle of the fundamental frequency ω using tailored bichromatic (ω, 2ω) counter-rotating circularly polarized laser fields with a molecular target.

We demonstrate the feasibility to control electron recollisions giving three returns per fundamental frequency cycle for generating circularly polarized (CP) attosecond pulse using tailored bichromatic (ω, 2ω) counter-rotating CP laser fields with molecular target.

Biological carbon fixation is a feasible strategy to reduce atmospheric carbon dioxide levels (CO2). In this platform, carbonic anhydrase (CA) enzyme is employed to accelerate the sequestration of CO2. The present work explored the effect of chaperone GroELS and TrxA-tag on improving soluble expression of the recombinant Sulfurihydrogenibium yellowstonense CA which activity and biomineralization capability were taken into consideration. At first, the expression of GroELS using the inducible T7 promoter and constitutive J23100 promoter were investigated. The results indicated that 1.4 folds increment of soluble protein and 100% of CA activity enhancement were achieved with GroELS co-expression driven by J23100 promoter. Furthermore, the involvement of TrxA fusion tag displayed a significant enhancement of soluble protein production which was about 2.67 times higher than that of original SyCA. Besides, co-expression with GroELS intensified the thermostability of SyCA at 60 °C owing to changes in the structural conformation of the protein, which was proved by an in vitro assay. The SyCA was further entrapped and immobilized into polyacrylamide gel (i.e., PAGE-SyCA). The biomineralization capability of the PAGE-SyCA and whole-cell (WC) was compared in a two-column system. After 5 cycles of reuse, PAGE-SyCA maintained 29.8% activity and formed 774 mg of CaCO3 solids in the B::JG strain. This study presents the recombinant engineering strategies to improve SyCA productivity, activity, thermostability, and effective carbon dioxide conversion.

We present the recent new developments of time-dependent Schrödinger equation and time-dependent density-functional theory for accurate and efficient treatment of the electronic structure and time-dependent quantum dynamics of many-electron atomic and molecular systems in intense laser fields. We extend time-dependent generalized pseudospectral (TDGPS) numerical method developed for time-dependent wave equations in multielectron systems. The TDGPS method allows us to obtain highly accurate time-dependent wave functions with the use of only a modest number of spatial grid point for complex quantum dynamical calculations. The usefulness of these procedures is illustrated by a few case studies of atomic and molecular processes of current interests in intense laser fields, including multiphoton ionization, above-threshold ionization, high-order harmonic generation, attosecond pulse generation, and quantum dynamical processes related to multielectron effects. We conclude this paper with some open questions and perspectives of multiphoton quantum dynamics of many-electron atomic and molecular systems in intense laser fields.

Recently, studies of high-order harmonics (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields as a source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup have received considerable attention. Here, we demonstrate the ability to control the electron recollisions giving three returns per one cycle of the fundamental frequency $\ensuremath{\omega}$ by using tailored bichromatic ($\ensuremath{\omega}$, $2\ensuremath{\omega}$) counter-rotating circularly polarized laser fields with a molecular target. The full control of the electronic pathway is first analyzed by a classical trajectory analysis and then extended to a detailed quantum study of ${\mathrm{H}}_{2}{}^{+}$ molecules in bichromatic ($\ensuremath{\omega}$, $2\ensuremath{\omega}$) counter-rotating circularly polarized laser fields. The radiation spectrum contains doublets of left- and right-circularly polarized harmonics in the XUV ranges. We study in detail the below-, near-, and above-threshold harmonic regions and describe how excited-state resonances alter the ellipticity and phase of the generated harmonic peaks.

Context. The Gaia spacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs. These asteroids have been already identified and have been numbered by the Minor Planet Center repository. Positions are provided for each Gaia observation at CCD level. As additional information, complementary to astrometry, the apparent brightness of SSOs in the unfiltered G band is also provided for selected observations. Aims. We explain the processing of SSO data, and describe the criteria we used to select the sample published in Gaia DR2. We then explore the data set to assess its quality. Methods. To exploit the main data product for the solar system in Gaia DR2, which is the epoch astrometry of asteroids, it is necessary to take into account the unusual properties of the uncertainty, as the position information is nearly one-dimensional. When this aspect is handled appropriately, an orbit fit can be obtained with post-fit residuals that are overall consistent with the a-priori error model that was used to define individual values of the astrometric uncertainty. The role of both random and systematic errors is described. The distribution of residuals allowed us to identify possible contaminants in the data set (such as stars). Photometry in the G band was compared to computed values from reference asteroid shapes and to the flux registered at the corresponding epochs by the red and blue photometers (RP and BP). Results. The overall astrometric performance is close to the expectations, with an optimal range of brightness G ∼ 12 - 17. In this range, the typical transit-level accuracy is well below 1 mas. For fainter asteroids, the growing photon noise deteriorates the performance. Asteroids brighter than G ∼ 12 are affected by a lower performance of the processing of their signals. The dramatic improvement brought by Gaia DR2 astrometry of SSOs is demonstrated by comparisons to the archive data and by preliminary tests on the detection of subtle non-gravitational effects., 0, info:eu-repo/semantics/published

The technology acceptance model (TAM) has been applied in various fields to study a wide range of information technologies. Although TAM has been developed in this research stream in Taiwan, TAM's issues of measurement have received scant attention. A robust model must perform measurement invariance across different respondent subgroups to ensure that various sample profiles have the same relationship. A survey of regarding E-portfolio system reuse intention was constructed, resulting in 360 valid responses across subgroups differing in gender, grade, and levels of willingness to share, to examine the measurement invariance of TAM. The results empirically support the validity of our TAM instrument for evaluating E-portfolio reuse intentions behavior. These findings suggest that men and women, differing grades, levels of willingness to share conceptualize the TAM construct in similarly. The implications of these results enable us to understand TAM's validity in E-portfolio acceptance research. This study explains individuals' intention of E-portfolio information platforms usage.This study performs the invariance analysis to understand the moderation of different subgroups in TAM.This study proposes an empirical case of verification process for TAM's invariance testing.

Generation of circularly polarized high-order harmonics is studied with the targets of diatomic molecules subject to bichromatic counter-rotating circularly polarized laser fields. It is also found that with the driving field polarized perpendicular to the molecular axis, even-order harmonics polarized along the molecular axis can be generated by heteronuclear molecules, even if the permanent dipole moment of the molecules is very small.

We study high-order-harmonic generation (HHG) by the incident laser beam in the Laguerre-Gaussian mode with a nonzero topological charge. We find that the harmonic signal in the central spot on the beam axis does not always vanish and depends on the distribution of the medium in the focal region of the incident laser beam. The HHG spectra on the beam axis can be controlled by changing the spatial medium distribution. General theoretical results are confirmed by calculations of HHG in the medium of argon atoms, with the single-atom response obtained by means of the time-dependent density functional theory.

Bundled carbon nanotube (CNT)-based sensor has been fabricated on paper substrate for chemical sensing applications. Integration of the sensor and fluidic channel was demonstrated for the potential development of a paper-based microfluidic device. In this work, electrical pH measurement of analyte solution was presented to show the functionality of the device. The device with the functions of fluidic transportation and chemical sensing was fabricated on a single paper. The bundled CNT-based sensor was first formed on a sheet of paper by vacuum filtration process. Hence, the hydrophilic channel across the sensor was defined by the application of polydimethylsiloxane (PDMS) material. Therefore, aqueous solution, e.g., sample, can be passively transported along the channels by wicking through the hydrophilic fibers of paper. The pH value of the solution can be electrically measured by the sensor. Determination of the pH value from 3 to 11 of the solutions was demonstrated by measuring the resistance change of the sensor. Because the proposed device is low cost, simple, flexible, and disposable, it is suitable for the development of the analytical device for the developing countries and harsh environments. Moreover, because CNT has excellent properties and can be functionalized by various molecules, the proposed paper-based microfluidic device has potential to realize more chemical and biological assays on paper with high sensitivity and specificity.

Recently, the study of near- and below- threshold regime harmonics as a potential source of intense coherent vacuum-ultraviolet radiation has received considerable attention. However, the dynamical origin of these lower harmonics, particularly for the molecular systems, is less understood and largely unexplored. Here we perform the first fully ab initio and high precision 3D quantum study of the below- and near-threshold harmonic generation of "Equation missing" molecules in an intense 800-nm near-infrared (NIR) laser field. Combining with a synchrosqueezing transform of the quantum time-frequency spectrum and an extended semiclassical analysis, we explore in-depth the roles of various quantum trajectories, including short- and long trajectories, multiphoton trajectories, resonance-enhanced trajectories, and multiple rescattering trajectories of the below- and near- threshold harmonic generation processes. Our results shed new light on the dynamical origin of the below- and near-threshold harmonic generation and various quantum trajectories for diatomic molecules for the first time.

Multiple rescattering processes play an important role in high-order harmonic generation (HHG) in an intense laser field. However, the underlying multi-rescattering dynamics are still largely unexplored. Here we investigate the dynamical origin of multiple rescattering processes in HHG associated with the odd and even number of returning times of the electron to the parent ion. We perform fully ab initio quantum calculations and extend the empirical mode decomposition method to extract the individual multiple scattering contributions in HHG. We find that the tunneling ionization regime is responsible for the odd number times of rescattering and the corresponding short trajectories are dominant. On the other hand, the multiphoton ionization regime is responsible for the even number times of rescattering and the corresponding long trajectories are dominant. Moreover, we discover that the multiphoton- and tunneling-ionization regimes in multiple rescattering processes occur alternatively. Our results uncover the dynamical origin of multiple rescattering processes in HHG for the first time. It also provides new insight regarding the control of the multiple rescattering processes for the optimal generation of ultrabroad band supercontinuum spectra and the production of single ultrashort attosecond laser pulse.

Electron multiple recollision dynamics under intense midinfrared laser fields is studied by means of the de Broglie--Bohm framework of Bohmian mechanics. Bohmian trajectories contain all the information embedded in the time-dependent wave function. This makes the method suitable to investigate the coherent dynamic processes for which the phase information is crucial. In this study, the appearance of the subpeaks in the high-harmonic-generation time-frequency profiles and the asymmetric fine structures in the above-threshold ionization spectrum are analyzed by the comprehensive and intuitive picture provided by Bohmian mechanics. The time evolution of the individual electron trajectories is closely studied to address some of the major structural features of the photoelectron angular distributions.

Below- and near-threshold harmonic generation provides a potential approach to achieve a high conversion efficiency of vacuum-ultraviolet and extreme-ultraviolet sources for the advancement of spectroscopy. Here, we perform a time-dependent density functional theory study for the nonperturbative treatment of below- and near-threshold harmonic generation of CO and ${\mathrm{N}}_{2}$ diatomic molecules subject to short near-infrared laser pulses and aligned parallel to the laser field polarization. We find that with the use of different driving laser pulse shapes, we can control and enhance harmonic generation through the excited-state resonance structures. Depending on the pulse shape, the enhancement can reach five to seven orders of magnitude as compared to the reference sine-squared laser pulse of the same duration. The results for different driving laser intensities are also presented and discussed in detail.

Photoelectron momentum distributions (PMDs) of the hydrogen atom driven by multicycle elliptically polarized strong laser fields are studied in detail, based on the numerical solution of the time-dependent Schr\"odinger equation and the Volkov wave propagation. Both short and long driving pulses of the 800-nm field are considered, as well as the ellipticity dependence, to describe the mechanism of symmetry breaking in the hydrogen-atom PMD. Moreover, we demonstrate that the value of a retardation angle in the longitudinal PMD can depend on the order of above-threshold ionization spectra.

A fabrication method for carbon nanotube (CNT)-based sensors on paper is proposed and provides a repeatable and well-controlled method for constructing a functional paper-based analytical device. The proposed method is based on vacuum filtration process with a metal mask covering on a filter paper for the definition of the sensor dimension. The length, width, and thickness of the CNT-based sensors are readily controlled by the metal mask and the weight of the CNT powder used during the filtration process, respectively. Homogeneous deposition of CNTs with well-defined dimensions on paper can be achieved. The CNT-based sensors showed linear I-V response and their resistances can be designed from 0.3 to [email protected] based on their dimensions. Moreover, the CNT-based sensor on paper has been demonstrated on the detection of the pH value of the analyte solution. It showed the CNT is sensitive to the chemical molecules and the CNT-based sensor is a possible candidate for chemical and biosensors. Thus, electrical bio-assays on paper-based microfluidics can be realized to develop low cost, sensitive, and specific diagnostic devices.

In the framework of the time-dependent density functional theory, we have performed 3D calculations of multiphoton ionization of Li and Be atoms by strong near-infrared laser fields. The results for the intensity-dependent probabilities of single and double ionization are presented. We make use of the time-dependent Krieger-Li-Iafrate exchange-correlation potential with self-interaction correction (TD-KLI-SIC). Such a potential possesses an integer discontinuity which improves description of the ionization process. However, we have found that the discontinuity of the TD-KLI-SIC potential is not sufficient to reproduce characteristic feature of double ionization.

An accurate three-dimensional numerical scheme for the De Broglie--Bohm framework of Bohmian mechanics is presented. This method is utilized to explore the subcycle multiphoton ionization dynamics of the hydrogen atom subject to intense near-infrared laser fields on the subfemtosecond time scale. The analysis of the time-dependent electron density reveals that several distinct density portions can be shaped and detached from the core within a half cycle of the laser field. As a complementary perspective, we identify several distinct groups of the Bohmian trajectories which represent the multiple detachments of the electron density at different times. The method presented provides very accurate electron densities and Bohmian trajectories that allow to uncover the origin of the formation of the transient and distinct electron structures seen in the multiphoton ionization processes.

We present an efficient high-order-harmonic optimal control scheme for the generation of the ultrabroad supercontinuum spectrum and an isolated ultrashort attosecond pulse in gases with a two-color mid-IR laser field. The optimal control scheme is implemented using a derivative-free unconstrained optimization algorithm called NEWUOA (NEW Unconstrained Optimization Algorithm). For illustration, the high-order-harmonic generation (HHG) of a hydrogen atom is considered for optimization. It is shown that optimally shaped laser waveforms can greatly enhance and extend the HHG plateau and efficiently generate an isolated ultrashort attosecond pulse. Moreover, by performing accurate semiclassical simulations and a detailed wavelet time-frequency analysis, we found that the optimized supercontinuum harmonics corresponding to long-trajectory electrons are responsible for an isolated ultrashort 21-as pulse.

We present a nonperturbative quantum study of high-order above-threshold detachment of H− in intense laser fields using an accurate one-electron model potential and a new time-dependent non-Hermitian Floquet approach. Detailed exploration of the electron energy and angular distributions is pursued for the laser field intensities 1010–1011 W cm−2 and wavelength 10.6 µm. In accordance with semiclassical predictions, the electron energy spectrum exhibits a plateau region in the higher energy part. Transformation of the electron angular distributions in the plateau region is discussed. The computational method involves the complex-scaling generalized pseudospectral (CSGPS) spatial discretization of the Hamiltonian and non-Hermitian time propagation of the time-evolution operator by means of the split-operator technique in the energy representation. The approach is designed for effective treatment of multiphoton processes in very intense and/or low-frequency laser fields, which are generally more difficult to treat using the conventional time-independent Floquet matrix techniques.

A scheme is proposed for realizing quantum entanglement, information transfer, CNOT gates, and SWAP gates with superconducting-quantum-interference-device (SQUID) qubits in cavity QED. In the scheme, the two logical states of a qubit are the two lowest levels of the SQUID. An intermediate level of the SQUID is utilized to facilitate coherent control and manipulation of quantum states of the qubits. The method presented here does not involve a real excitation of the intermediate levels during the operations. Thus, decoherence due to energy relaxation of intermediate levels is minimized. In addition, the present method does not require the adjustment of the SQUID level spacings, which simplifies the operation significantly.

Article history: We present a numerical method based on the generalized pseudospectral discretization in prolate spheroidal coordinates and split-operator time propagation. The method has been applied for the study of multiphoton processes of H + and N2 diatomic molecules in intense laser fields. It proves very accurate while using only moderate computer resources.

We present an ab initio investigation of the below-threshold harmonic generation of helium (He) atoms in few-cycle infrared laser fields by accurately solving the time-dependent Schr\"odinger equation and Maxwell's equation simultaneously. We find that the enhancement of the below-threshold harmonic generation only occurs to near the resonance structure of He, for which this mechanism is in agreement with the recent experimental study [M. Chini et al., Nat. Photonics 8, 437 (2014)]. Moreover, we perform the quantum and semiclassical trajectories analysis, including both the atomic potential and the laser field, as well as the synchrosqueezed transform of the harmonic spectra. Our results reveal that several multirescattering trajectories contribute to the resonance-enhanced below-threshold harmonic generation.

We perform an ab initio and accurate exploration of the subcycle transient multiphoton-ionization dynamics of atomic and molecular systems subject to intense near-infrared laser fields on the subfemtosecond time scale. Multiple-ionization bursts within a single optical cycle are found in the time-dependent ionization rates not only for diatomic molecules ${{\mathrm{H}}_{2}}^{+}$ and ${\mathrm{HHe}}^{2+}$, but also for the hydrogen atom. The analysis of the electron density reveals that several distinct density portions can be shaped and detached from the target within a half cycle of the laser field.

In the framework of the self-interaction-free time-dependent density-functional theory, we have performed three-dimensional (3D) ab initio calculations of He atoms in near-infrared (NIR) laser fields subject to excitation by a single extreme ultraviolet (XUV) attosecond pulse (SAP). We have explored the dynamical behavior of the subcycle high harmonic generation (HHG) for transitions from the excited states to the ground state and found oscillation structures with respect to the time delay between the SAP and NIR fields. The oscillatory pattern in the photon emission spectra has a period of $\ensuremath{\sim}$$1.3$ fs which is half of the NIR laser optical cycle, similar to that recently measured in the experiments on transient absorption of He [M. Chini et al., Sci. Rep. 3, 1105 (2013)]. We present the photon emission spectra from $1s2p$, $1s3p$, $1s4p$, $1s5p$, and $1s6p$ excited states as functions of the time delay. We explore the subcycle Stark shift phenomenon in NIR fields and its influence on the photon emission process. Our analysis reveals several interesting features of the subcycle HHG dynamics and we identify the mechanisms responsible for the observed peak splitting in the photon emission spectra.

We propose an efficient method for the generation of ultrabroadband supercontinuum spectra and isolated ultrashort attosecond laser pulses from He atoms with two-color midinfrared laser fields. High-order harmonic generation (HHG) is obtained by solving the time-dependent Schr\"odinger equation accurately by means of the time-dependent generalized pseudospectral method. We found that the optimizing two-color midinfrared laser pulse allows the HHG cutoff to be significantly extended, leading to the production of an ultrabroadband supercontinuum. As a result, an isolated 18-attosecond pulse can be generated directly by the superposition of the supercontinuum harmonics. To facilitate the exploration of the ultrashort attosecond generation mechanisms, we perform both a semiclassical simulation and a wavelet time-frequency transform.

We present a scheme to achieve maximally entangled states, controlled phase-shift gate, and SWAP gate for two superconducting-quantum-interference-device (SQUID) qubits, by placing SQUIDs in a microwave cavity. We also show how to transfer quantum information from one SQUID qubit to another. In this scheme, no transfer of quantum information between the SQUIDs and the cavity is required, the cavity field is only virtually excited and thus the requirement on the quality factor of the cavity is greatly relaxed., Comment: 10 pages, 4 figures

We demonstrate a dramatic enhancement of the below-threshold harmonics in the vicinity of atomic resonances. The dependence on the driving laser carrier-envelope phase suggests a nonperturbative mechanism. Phase matching promises scalability to microJoule pulse energies.

We perform a nonperturbative study of the effect of static magnetic fields on the multiple high-order harmonic generation (HHG) processes of atomic H in intense pulsed laser fields. The time-dependent Schr?dinger equation in three spatial dimensions can be solved accurately and efficiently by means of the recently developed time-dependent generalized pseudospectral method (Tong X M and Chu S I 1997 Chem. Phys. 217 119). We found that the presence of a static magnetic field perpendicular to the laser field polarization direction can introduce a second HHG plateau, allowing significant extension of the cut-off. The high harmonics in the second plateau reach a maximum enhancement when the cyclotron frequency of the electron is about equal to one half of the laser frequency. Through a detailed time-frequency wavelet analysis of the HHG spectra, we have identified a `synchrotron radiation'-like new mechanism responsible for the production of the second plateau.

We present a scheme for the production of circularly polarized multiple high-order harmonic generation (HHG). The proposed experimental setup involves the use of two-color laser fields, consisting of a circularly polarized fundamental laser field and a linearly polarized second-harmonic laser field, in crossed-beam configuration. The feasibility of such a scheme is demonstrated by an ab initio quantal study of the HHG power spectrum of He atoms by means of the time-dependent density-functional theory with optimized effective potential and self-interaction correction recently developed. The theoretical study also provides insights regarding the different mechanisms responsible for the production of HHG in different energy regimes as well as the mechanism for the generation of continuous background radiation.

We present a time-dependent density-functional theory (TDDFT) with optimized effective potential (OEP) and self-interaction correction (SIC) for nonperturbative treatment of multiphoton and nonlinear optical processes of many-electron systems in intense laser fields. The resulting TDOEP/KLI-SIC equations are structurally similar to the time-dependent Hartree-Fock equations but include the many-body effects through an orbital-independent single-particle local time-dependent exchange-correlation (xc) potential. The method is applied to the all-electron study of the coherent control of multiple high-order harmonic generation (HHG) of He atoms in two-color mixed laser fields. A generalized pseudospectral time propagation method is introduced for efficient and accurate solution of the TDOEP/KLI-SIC equations in three spatial dimensions. It is found that the mixing of a strong second-harmonic (527 nm) field with a weak fundamental (1053 nm) field can lead to the production of both odd and even harmonics simultaneously with relatively high yield. Further, the relative efficiency of the HHG production can be controlled by varying the relative polarization of the two laser beams. The theoretical predictions are in accord with recent experimental observations. (C) 1998 John Wiley & Sons, Inc.

We generalize the Floquet formulation of the time-dependent density . w . x functional theory TDDFT Telnov and Chu, Chem. Phys. Lett. 264, 466 1997 to the case of many-electron systems in multicolor or polychromatic time-dependent fields. It is shown that the time-dependent Kohn)Sham equations can be transformed into an equivalent time-independent infinite-dimensional Floquet Hamiltonian eigenvalue problem. For the case of bound-free transitions, we introduce the notion of complex density and present a non-Hermitian many-mode Floquet formulation of TDDFT. A procedure is presented for the determination of the complex quasi-energies and the calculation of the total and partial ionization rates from individual electron orbitals. The theory is illustrated by a case study of multiphoton ionization of He atoms in the presence of an intense 248 nm laser field and its third harmonic. Novel intensity- and phase-dependent behavior of multiphoton processes in two-color fields is reported.

We present a new time-dependent method for accurate and efficient non-perturbative treatment of multiple high-order harmonic generation (HHG) in intense laser fields. The time development of the wavefunction is obtained by a new split-operator time-propagation technique in the energy representation. The generalized pseudospectral technique is extended to perform an optimal spatial grid discretization, leading to significant improvement of the quality of the wavefunction over that obtained by the equal-spacing spatial discretization techniques. The accuracy of the method is demonstrated by several benchmark calculations including the excellent agreement of the HHG power spectra in length and acceleration forms. The method is applied to a detailed study of the coherent control of HHG spectra of atomic hydrogen in intense ultrashort pulsed laser fields with or without the chirp. Several novel chirp-dependent and pulse-duration-dependent phenomena are predicted. Comparison with available experimental observation is made.

BACKGROUND Data are limited on the efficacy and safety of pegylated interferon plus ribavirin for patients with hepatitis C virus genotype 1 (HCV-1) receiving hemodialysis. OBJECTIVE To compare the efficacy and safety of combination therapy with pegylated interferon plus low-dose ribavirin and pegylated interferon monotherapy for treatment-naive patients with HCV-1 receiving hemodialysis. DESIGN Open-label, randomized, controlled trial. (ClinicalTrials.gov: NCT00491244). SETTING 8 centers in Taiwan. PATIENTS 205 treatment-naive patients with HCV-1 receiving hemodialysis. INTERVENTION 48 weeks of pegylated interferon-α2a, 135 µg weekly, plus ribavirin, 200 mg daily (n = 103), or pegylated interferon-α2a, 135 µg weekly (n = 102). MEASUREMENTS Sustained virologic response rate and adverse event-related withdrawal rate. RESULTS Compared with monotherapy, combination therapy had a greater sustained virologic response rate (64% vs. 33%; relative risk, 1.92 [95% CI, 1.41 to 2.62]; P < 0.001). More patients receiving combination therapy had hemoglobin levels less than 8.5 g/dL than those receiving monotherapy (72% vs. 6%; risk difference, 66% [CI, 56% to 76%]; P < 0.001). Patients receiving combination therapy required a higher dosage (mean, 13 946 IU per week [SD, 6449] vs. 5833 IU per week [SD, 1169]; P = 0.006) and longer duration (mean, 29 weeks [SD, 9] vs. 18 weeks [SD, 7]; P = 0.004) of epoetin-β than patients receiving monotherapy. The adverse event-related withdrawal rates were 7% in the combination therapy group and 4% in the monotherapy group (risk difference, 3% [CI, -3% to 9%]). LIMITATION Open-label trial; results may not be generalizable to patients on peritoneal dialysis. CONCLUSION In treatment-naive patients with HCV-1 receiving hemodialysis, combination therapy with pegylated interferon plus low-dose ribavirin achieved a greater sustained virologic response rate than pegylated interferon monotherapy. PRIMARY FUNDING SOURCE National Center of Excellence for Clinical Trial and Research.

We present a theoretical study of transient absorption spectra of laser-dressed hydrogen atoms, based on numerical solutions of the time-dependent Schr\"odinger equation. The timing of absorption is controlled by the delay between an extreme ultra violet (XUV) pulse and an infrared (IR) laser field. The XUV pulse is isolated and several hundred attoseconds in duration, which acts as a pump to drive the ground-state electron to excited $p$ states. The subsequent interaction with the IR field produces dressed states, which manifest as sidebands between the 1s-$np$ absorption spectra separated by one IR-photon energy. We demonstrate that the population of dressed states is maximized when the timing of the XUV pulse coincides with the zero crossing of the IR field, and that their energies can be manipulated in a subcycle time scale by adding a chirp to the IR field. An alternative perspective to the problem is to think of the XUV pulse as a probe to detect the dynamical ac Stark shifts. Our results indicate that the accidental degeneracy of the hydrogen excited states is removed while they are dressed by the IR field, leading to large ac Stark shifts. Furthermore, we observe the Autler-Townes doublets for the $n=2$ and 3 levels using the 656 nm dressing field, but their separation does not agree with the prediction by the conventional three-level model that neglects the dynamical ac Stark shifts.

With the popularity of wireless networks, it needs to support user's mobility cross different base stations, hence, the handover mechanism becomes an important issue. When the user frequently moves between two cells, it will occur the Ping-Pong effect that increases the delay time and reduces the efficiency of system. In this paper, we proposed a new handover mechanism over relay networks to reduce the unnecessary handover. It uses the value of signal to interference and noise ratio (SINR) and the parameter of distance to make handover decision. The simulation results indicate the proposed handover mechanism can reduce more than 8% of the handover number in average in comparison to the competing method in the best case.