Above-threshold ionization of hydrogen atom in chirped laser fields

Above-threshold ionization （ATI） of a hydrogen atom exposed to chirped laser fields is investigated theoretically by solving the time-dependent Schrodinger equation. By comparing the energy spectra, the two-dimensional momentum spectra, and the angular distributions of photoelectron for the laser pulses with different chirp rates, we show a very clear chirp dependence both in the multiphoton and tunneling ionization processes but no chirp dependence in the single-photon ionization. We find that the chirp dependence in the multiphoton ionization based ATI can be attributed to the excited bound states. In the single-photon and tunneling ionization regimes, the electron can be removed directly from the ground state and thus the excited states may not be very important. It indicates that the chirp dependence in the tunneling ionization based ATI processes is mainly due to the laser pulses with different chirp rates,

Endoscopic retrograde cholangiopancreatography in the treatment of pancreaticopleural fistula in children

BACKGROUND Pancreaticopleural fistula(PPF)is a rare disease,especially in children.Conservative treatment and surgery are traditional therapies,but surgery is invasive.The emergence of endoscopic retrograde cholangiopancreatography(ERCP)has provided a new noninvasive treatment for PPF and may become the first choice for children with PPF.AIM To explore the treatment response to ERCP for PPF in children.METHODS Seven children with PPF were hospitalized in the Gastroenterology Department of Beijing Children’s Hospital from December 2007 to May 2019.Data on these seven patients’clinical characteristics,diagnosis,treatments,and outcomes were analyzed,and their treatment responses following surgery and ERCP were compared.The correlation between the length of hospital stay and conservative treatment was analyzed.Peer-reviewed articles written in English and Chinese published from January 2009 to December 2019 were obtained from various open data sources and reviewed.RESULTS The seven patients comprised three boys and four girls with a mean age of 6.57±3.26 years.The main symptoms were chest tightness and pain(n=4),intermittent fever(n=3),dyspnea(n=3),and abdominal pain(n=1),and all patients had bloody pleural effusion.All seven patients were diagnosed with PPF by magnetic resonance cholangiopancreatography,and all were initially treated conservatively for a mean of 34.67±22.03 d with a poor response.Among five patients who underwent ERCP,one required surgery because of intubation failure;thus,the success rate of ERCP was 80%.Two patients were successfully treated with surgery(100%).The postoperative hospital stay of the two patients treated by surgery was 20 and 30 d,respectively(mean of 25 d),and that of the four patients treated by ERCP ranged from 12 to 30 d(mean of 19.25±8.85 d).The recovery time after ERCP was short[time to oral feeding,4-6 d(mean,5.33±1.15 d);duration of closed thoracic drainage,2-22 d(mean,13.3 d)].Analysis of previous cases of PPF published worldwide during the past decade showed that the treatment success rate of ERCP is not lower than that of surgery.There was no significant difference in the postoperative hospital stay between surgery(16±10.95 d)and ERCP(18.7±6.88 d,P>0.05).A positive linear correlation was found between the overall hospital stay and ERCP intervention time(R2=0.9992).CONCLUSION ERCP is recommended as the first-choice treatment for PPF in children.ERCP should be performed as early as possible if conditions permit.

Broadband Terahertz Wave Generation from Monolayer Graphene Driven by Few-Cycle Laser Pulse

We theoretically investigate the characteristics of terahertz(THz) radiation from monolayer graphene exposed to normal incident few-cycle laser pulses, by numerically solving the extended semiconductor Bloch equations. Our simulations show that the THz spectra in low frequency regions are highly dependent on the carrier envelope phase(CEP) of driving laser pulses. Using an optimal CEP of few-cycle laser pulses, we can obtain broadband strong THz waves, due to the symmetry breaking of the laser-graphene system. Our results also show that the strength of the THz spectra depend on both the intensity and central wavelength of the laser pulses. The intensity dependence of the THz wave can be described by the excitation rate of graphene, while wavelength dependence can be traced back to the band velocity and the population of graphene. We find that a near single-cycle THz pulse can be obtained from graphene driven by a mid-infrared laser pulse.

Novel mutation of the TJP2 gene in a Chinese child with progressive cholestatic liver disease coexistent with hearing impairment

To the Editor:Diagnosis and management of infantile cholestatic liver disease with unknown etiology remain challenging.With recent rapid development of genetic technology,several gene mutations have been found to be the cause of this disease[1].Progressive familial intrahepatic cholestasis(PFIC)is a group of rare diseases that mainly occur in neonates and infants.Some children might progress to end-stage liver disease that requires liver transplantation.

Acute pulmonary embolism originating from upper limb venous thrombosis following breast cancer surgery:Two case reports

BACKGROUND Upper limb venous thrombosis(ULVT)is rarer than lower-extremity deep venous thrombosis,and is related to Paget-Schroetter syndrome,central venous catheterization,and malignancy.There are few reports of pulmonary embolism(PE)from upper-extremity vein thrombosis due to surgery.Herein,we report two cases of PE that originated from upper limb venous thrombosis on the surgical side in two patients undergoing modified radical mastectomy for breast cancer.These cases challenge the traditional theory that PE originate only from the lower extremities.CASE SUMMARY We describe two female patients,aged 68 and 65 years,respectively,who had undergone modified radical mastectomy for breast cancer.They did not have a central venous catheter and did not undergo preoperative neoadjuvant chemotherapy.They were transferred to the intensive care unit due to symptomatic PE on the first day after surgery.Colour Doppler ultrasound identified fresh thrombosis in their upper limb veins,which was the presumed source of the PE.They all received anticoagulation therapy,and one of them experienced bleeding that required discontinuation of the drug.Ultimately,they were discharged in stable condition.CONCLUSION ULVT as a source of PE after breast cancer surgery cannot be ignored.

An improved method for the investigation of high-order harmonic generation from graphene

High-order harmonic generation (HHG) of bulk crystals in strong laser field is typically investigated with semiconductor Bloch equations (SBEs). However, in the length gauge, it suffers from the divergence for the crystals with a zero band gap, such as graphene, using both Bloch- and Houston-states expansion methods. Here, we present a method of solving the SBEs based on time-dependent Bloch basis, which is equivalent to semiconductor Bloch equations in the velocity gauge. Using this method, we investigate the HHG of a single-layer graphene. It is found that our results for population are in good agreement with the other results. For a initial condition py = 0, we find the electrons just move in single valence band or conduction band, which are in accord with classical results. Our simulations on the HHG dependence of polarization of driving laser pulse confirm that 5th, 7th, and 9th harmonic yields increase to the maximal value when laser ellipticity ε ≈ 0.3. What is more, similar to the case of atoms in the laser field, the total strength of 3rd harmonic decrease monotonically with the increase of ε. In addition, we simulate the dependence of HHG on crystallographic orientation with respect to the polarization direction of linear mid-infrared laser pulse, and the results reveal that for higher harmonics, their radiation along with the change of rotation angle θ reflects exactly the sixfold symmetry of graphene. Our method can be further used to investigate the behaviors of other materials having Dirac points (i.e., surface states of topological insulators) in the strong laser fields.

High-order harmonic generation of Li^+ with combined infrared and extreme ultraviolet fields

We investigate high-order harmonic generation （HHG） ofLi＋ ion driven by an intense infrared （IR） laser field in corn-bination with a weak XUV pulse. To achieve this, we first construct an accurate single-active electron angular-momentumdependent model potential of Li＋ ion, by which the accurate singlet energy levels of Li＋ for the ground state and excited states with higher quantum numbers can be obtained. Then, we solve numerically the three dimensional time-dependent Schr/Sdinger equation of Li＋ ion by means of the generalized pseudospectral method to obtain HHG. Our results show that the strength of assisted XUV is not amplified during the harmonic generation process, but the yield of HHG power spectrum in the whole plateau has a significant enhancement. Furthermore, the optimal phase delay between the IR and XUV pulses allows the production of ultrabroadband supercontinuum spectra. By superposing some harmonics, a strong new single 27-attosecond ultrashort pulse can be obtained.

Dynamic stabilization of Na atom in an intense pulsed laser field

We investigate theoretically the ionization properties of the valence electron for the alkali metal atom Na in an intense pulsed laser field by solving numerically the time-dependent Schrodinger equation with an accurate l-dependent model potential.By calculating the variations of the ionization probabilities with laser peak intensity for wavelengths ranging from 200 nm to 600 nm,our results present a dynamic stabilization trend for the Na atom initially in its ground state（3 s） and the excited states（3 p and 4 s） exposed to an intense pulsed laser field.Especially a clear ＂window＂ of dynamic stabilization at lower laser intensities and longer wavelengths for the initial state 4 s（the second excited state） is found.By analyzing the time-dependent population distributions of the valence electron in the bound states with the different values of principal quantum number n and orbital quantum number l,we can attribute the dynamic stabilization to the periodic population in the low-excited states since the valence electron oscillates rapidly between the lowly excited states and the continuum states.

New Insight into the Graphene Based Films Prepared from Carbon Fibers

In this work, ultrathin sections from longitudinal polyacrylonitrile (PAN) based T700 and T300 carbon fibers were prepared by ultramicrotomy, a promising graphene based thin films were developed in one step at ambient temperature. It is investigated that the network-graphene planes composed with carbon atoms are partly straight and partly twisted in the thin films prepared from T700 carbon fibers, the distance between the carbon atoms of network-graphene plane decreases, the order design of graphene in the films prepared from T700 carbon fibers is denser and its arrangement shows a preferred orientation along the drawing direction, its consistency of the neighboring graphene based planes is better, moreover, the relative content of the forming SP2-hybridized orbit of carbon atoms in the films prepared from T700 carbon fibers is higher, in the other words, the fact of the graphene based film prepared from carbon fibers without having the characteristic of skin-core structure has been verified.

CEPC Technical Design Report

The Circular Electron Positron Collider(CEPC)is a large scientific project initiated and hosted by China,fostered through extensive collaboration with international partners.The complex comprises four accelerators:a 30 GeV Linac,a 1.1 GeV Damping Ring,a Booster capable of achieving energies up to 180 GeV,and a Collider operating at varying energy modes(Z,W,H,and tt).The Linac and Damping Ring are situated on the surface,while the subterranean Booster and Collider are housed in a 100 km circumference underground tunnel,strategically accommodating future expansion with provisions for a potential Super Proton Proton Collider(SPPC).The CEPC primarily serves as a Higgs factory.In its baseline design with synchrotron radiation(SR)power of 30 MW per beam,it can achieve a luminosity of 5×10^(34)cm^(-2)s^(-1)per interaction point(IP),resulting in an integrated luminosity of 13 ab^(-1)for two IPs over a decade,producing 2.6 million Higgs bosons.Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons,facilitating precise measurements of Higgs coupling at sub-percent levels,exceeding the precision expected from the HL-LHC by an order of magnitude.This Technical Design Report(TDR)follows the Preliminary Conceptual Design Report(Pre-CDR,2015)and the Conceptual Design Report(CDR,2018),comprehensively detailing the machine's layout,performance metrics,physical design and analysis,technical systems design,R&D and prototyping efforts,and associated civil engineering aspects.Additionally,it includes a cost estimate and a preliminary construction timeline,establishing a framework for forthcoming engineering design phase and site selection procedures.Construction is anticipated to begin around 2027-2028,pending government approval,with an estimated duration of 8 years.The commencement of experiments and data collection could potentially be initiated in the mid-2030s.

Anti-inflammatory effects of Tao Hong Si Wu Tang in mice with lung cancer and chronic obstructive pulmonary disease

BACKGROUND Lung cancer(LC)combined with chronic obstructive pulmonary disease(COPD)is a common combination of comorbidities.Anti-inflammation and modulation of oxidative/antioxidative imbalance may prevent COPD-induced LC,and are also crucial to the treatment of LC combined with COPD.Modern studies have shown that Tao Hong Si Wu Tang(THSW)has vasodilatory,anti-inflammatory,anti-fatigue,anti-shock,immunoregulatory,lipid-reducing,micronutrient-supplementing,and anti-allergy effects.AIM To observe the effects of THSW on COPD and LC in mice.METHODS A total of 100 specific pathogen-free C57/BL6 mice were randomly divided into five groups:Blank control group(group A),model control group(group B),THSW group(group C),IL-6 group(group D),and THSW+IL-6 group(group E),with 20 mice in each group.A COPD mouse model was established using fumigation plus lipopolysaccharide intra-airway drip,and an LC model was replicated by in situ inoculation using the Lewis cell method.RESULTS The blank control group exhibited a clear alveolar structure.The model control and IL-6 groups had thickened alveolar walls,with smaller alveolar lumens,interstitial edema,and several inflammatory infiltrating cells.Histopathological changes in the lungs of the THSW and THSW+IL-6 groups were less than those of the model control group.The serum IL-1β,IL-6,and TNF-αlevels and IL-6R,JAK,p-JAK,STAT1/3,p-STAT1/3,FOXO,p-FOXO,and IL-7R expression levels in lung tissues of mice in the rest of the groups were significantly higher than those of the blank control group(P<0.01).Compared with the model control group,the IL-6 group demonstrated significantly higher levels for the abovementioned proteins in the serum and lung tissues(P<0.01),and the THSW group had significantly higher serum IL-1β,IL-6,and TNF-αlevels and IL-7R expression levels in lung tissues(P<0.01)but significantly decreased IL-6R,JAK,p-JAK,STAT1/3,p-STAT1/3,FOXO,p-FOXO,and IL-7R levels(P<0.01).CONCLUSION THSW reduces the serum IL-1β,IL-6,and TNF-αlevels in the mouse model with anti-inflammatory effects.Its antiinflammatory mechanism lies in inhibiting the overactivation of the JAK/STAT1/3 signaling pathway.

Diagnosis of intellectual disability/global developmental delay via genetic analysis in a central region of China

Background:Advanced technology has become a valuable tool in etiological studies of intellectual disability/global developmental delay(ID/GDD).The present study investigated the role of genetic analysis to confirm the etiology in ID/GDD patients where the cause of the disease was uncertain in central China.Methods:We evaluated 1051 ID/GDD children aged 6 months to 18 years from March 2009 to April 2017.Data concerning basic clinical manifestations were collected,and the method of etiology confirmation was recorded.Genome-wide copy number variations(CNVs)detection and high-throughput sequencing of exons in the targeted regions was performed to identify genetically-based etiologies.We compared the incidence of different methods used to confirm ID/GDD etiology among groups with differing degrees of ID/GDD using the Chi-square or Fisher exact probability test.Results:We recruited 1051 children with mild(367,34.9%),moderate(301,28.6%),severe(310,29.5%),and profoundly severe(73,6.9%)ID/GDD.The main causes of ID/GDD in the children assessed were perinatal factors,such as acquired brain injury,as well as single gene imbalance and chromosomal gene mutation.We identified karyotype and/or CNVs variation in 46/96(47.9%)of cases in severe ID/GDD patients,which was significantly higher than those with mild and moderate ID/GDD of 34/96(35.4%)and 15/96(15.6%),respectively.A total of 331/536(61.8%)patients with clear etiology have undergone genetic analysis while 262/515(50.9%)patients with unclear etiology have undergone genetic analysis(x^2=12.645,P<0.001).Gene structure variation via karyotype analysis and CNV detection increased the proportion of children with confirmed etiology from 51.0%to 56.3%,and second-generation high-throughput sequencing dramatically increased this to 78.9%.Ten novel mutations were detected,recessive mutations in X-linked genes(ATPase copper transporting alpha and bromodomain and WD repeat domain containing 3)and dominant de novo heterozygous mutations in X-linked genes(cyclin-dependent kinase like 5,protocadherin 19,IQ motif and Sec7 domain 2,and methyl-CpG binding protein 2)were reported in the study.Conclusions:The present study indicates that genetic analysis is an effective method to increase the proportion of confirmed etiology in ID/GDD children and is highly recommended,especially in ID/GDD children with uncertain etiology.

Dissipation-induced topological phase transition and periodic-driving-induced photonic topological state transfer in a small optomechanical lattice

We propose a scheme to investigate the topological phase transition and the topological state transfer based on the small optomechanical lattice under the realistic parameters regime.We find that the optomechanical lattice can be equivalent to a topologically nontrivial Su-Schrieffer Heeger(SSH)model via designing the effective optomechanical coupling.Especially,the optomechanical lattice experiences the phase transition between topologically nontrivial SSH phase and topologically trivial SSH phase by controlling the decay of the cavity field and the opto mechanical coupling.We stress that the to pological phase transition is mainly induced by the decay of the cavity field,which is counter-intuitive since the dissipation is usually detrimental to the system.Also,we investigate the photonic state transfer between the two cavity fields via the topologically protected edge channel based on the small optomechanical lattice.We find that the quantum st ate transfer assisted by the topological zero energy mode can be achieved via implying the external lasers with the periodical driving amplitudes into the cavity fields.Our scheme provides the fundamental and the insightful explanations towards the mapping of the photonic topological insulator based on the micro-nano optomechanical quantum optical platform.

Doubly-charged scalar in four-body decays of neutral flavored mesons

We study the four-body decays of neutral flavored mesons,including■,and■.These processes,which could be induced by a hypothetical doubly-charged scalar particle,do not conserve the lepton number.Assuming,as an example,that the mass of the doubly-charged particle is 1000 Ge V,and using the upper bounds of the couplings,we calculate the branching ratios of different channels.For■,and,it is of the order of 10^(-30),10^(-32)–10^(-29),and 10^(-33)–10^(-28),respectively.Based on the experimental results for the■channels,we also find the upper limit for the

Determination of structure parameters in strong-field ionization models of atoms

The Ammosov–Delone–Krainov(ADK) and Perelomov–Popov–Terent'ev(PPT) ionization models were widely used in strong-field physics and attosecond science due to their many attractive advantages such as simpler analytical formula, less computational demands, and satisfied accuracy of ionization rate. Based on the density-functional theory, we systematically determine accurate structure parameters of 25 atoms, 24 positive ions and 13 negative ions and tabulate for future applications. The wave function with correct asymptotic behavior is obtained by solving the time-independent Schr?dinger equation with B-spline basis sets and the accurate structure parameters are extracted from this wave function in the asymptotic region. The accuracies of structure parameters are carefully examined by comparing the ionization probabilities(or yields) calculated by PPT and ADK models with those of solving the threedimensional time-dependent Schr?dinger equation and the experimental data.

Revisiting the heavy vector quarkonium leptonic widths

We revisit the heavy quarkonium leptonic decays ψ(nS)→■^+■^- and Υ(nS)→■^+■^- using the Bethe-Salpeter method.The emphasis is on the relativistic corrections.For the ψ(1S-5S)decays,the relativistic effects are 22-2^+3%,34-2^+5%,41-6^+6%,52-13^+11% and 62-12^+14%,respectively.For the Υ(1S-5S) decays,the relativistic effects are 14-2^+1%,23-3^+0%,20-2^+8%,21-7^+6% and 28-7^+2%,respectively.Thus,the relativistic corrections are large and important in heavy quarkonium leptonic decays,especially for the highly excited charmonium.Our results forΥ(nS)→■^+■^- are consistent with the experimental data.

Spatio-Temporal Expression Patterns of Aurora Kinases A, B in Mouse Zygotes during the First Mitosis

Objective To investigate the expression and localization of Aurora kinase A （A URKA ） and Aurora kinase B （A URKB） in mouse zygotes during the process of the first mitosis. Methods Quantitative real-time RT-PCR and Western blotting were performed to analyze the expression of AURKA and AURKB. The subcellular location of AURKA and A URKB was studied by confocal microscopy. Results A URKA and A URKB were increasingly expressed from phase G1 and peaked at phase M. After the entrance into mitosis A URKB became the predominant form both in mRNA and protein levels. The proteins of A URKA and A URKB both distributed in the cytoplasm and were associated with nucleus during the first mitosis of mouse zygotes, with some details in different. Conclusion The expression and localization of Aurora kinases A and B was in a cell- cycle regulated manner during the process of the cleavage of mouse zygotes. This discovery will aid in future investigations on their specific roles and molecular mecha- nisms in the regulation of mammalian early embryonic development.