Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a...Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a big challenge.Herein,a three-dimensional(3D)hierarchical W_(18)O_(49)/WTe_(2) hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO_(3).The light absorption towards near-infrared spectral region and CO_(2) adsorption are enhanced by the formation of half-metal WTe_(2) and the unique hierarchical hollow architecture.Combining with the generation of oxygen vacancy with strengthened CO_(2) capture,the photothermal effect on the samples can be sufficiently exploited for activating the CO_(2) molecules.In particular,the close contact between W_(18)O_(49)and WTe_(2) largely promotes the photoinduced charge separation and mass transfer,and thus the~*CHO intermediate formation and fixedness are facilitated.As a result,the C-C coupling can be evoked between tungsten and tellurium atoms on WTe_(2).The ethylene production by optimized W_(18)O_(49)/WTe_(2) reaches 147.6μmol g^(-1)with the selectivity of 80%.The in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C-C coupling.The half-metallic WTe_(2) cocatalyst proposes a new approach for efficient CO_(2) conversion with solar energy,and may especially create a new platform for the generation of multi-carbon products.展开更多
By using first-principles electronic structure calculations,we predict a new two-dimensional half-metallic ferromagnet(2DHMF)with distorted square structure,i.e.,the LiCrTe_(2) monolayer.The results show that the LiCr...By using first-principles electronic structure calculations,we predict a new two-dimensional half-metallic ferromagnet(2DHMF)with distorted square structure,i.e.,the LiCrTe_(2) monolayer.The results show that the LiCrTe_(2) monolayer is dynamically,thermally,and mechanically stable,and takes a large in-plane magnetic anisotropy,a wide spin gap,a large magnetization,and a very high Curie temperature.Under a biaxial strain ranging from-5% to+5%,the ferromagnetism,half-metallicity,and high Curie temperature are maintained well.Both tensile and compressive strains can significantly increase the magnitude of the magnetocrystalline anisotropy energy(MAE)and a transition from in-plane easy-x(y)-axis to out-of-plane easy-z-axis occurs when the compressive strain exceeds 1%.Our systematic study of the LiCrTe_(2) monolayer enables its promising applications in spintronics.展开更多
The geometrical structures of wurtzite CrX (X=As, Sb, O, Se, and Te) were optimized, then their electric and magnetic properties were investigated by the first-principle calculations within the generalized gradient ...The geometrical structures of wurtzite CrX (X=As, Sb, O, Se, and Te) were optimized, then their electric and magnetic properties were investigated by the first-principle calculations within the generalized gradient approximation for the exchange-correlation functional based on the density functional theory. These Cr-phosphides and Cr-sulphides were predicted to be half-metallic ferromagnets whose spin-polarization at the Fermi level is absolutely 100%. The molecular magnetic moments of Cr-phosphides and Cr-sulphides are 3.00 and 4.00 μB, which arise mainly from Cr-ions, respectively. There is ferromagnetic coupling in both Cr- phosphides and Cr-sulphides. The Curie temperatures of Cr-sulphides and Cr-phosphides are high. The electronic structures of Cr-ions are a1g^2↑↓t1u^4↑↓t1u^1↑↓eg^2↑↓in Cr-phosphides and a1g^2↑↓t1u^4↑↓t1u^1↑t2g^3↑in Cr-sulphides, respectively.展开更多
The electronic structure and half-metallicity of molecule-based ferromagnet Cr[N(CN)2]2 have been investigated using first-principles with generalized gradient approximation. The total energy, spin-polarized electro...The electronic structure and half-metallicity of molecule-based ferromagnet Cr[N(CN)2]2 have been investigated using first-principles with generalized gradient approximation. The total energy, spin-polarized electronic band structure, density of states (DOSs) and spin magnetic moments were all calculated. The calculations reveal that the compound Cr[N(CN)2]2 is a really half-metallic ferromagnet with a integral magnetic moment of 2.0000 μB per molecule in the optimized lattice constant. Based on the spin distribution and the DOS, it is found that the total magnetic moment is mainly from the Cr2+ with relative small contribution from C and N atoms. The sensitivity of the half-metallicity to small change in lattice constant is also discussed.展开更多
Using THz emission spectroscopy,we investigate the elementary spin dynamics in ferromagnetic single-layer Fe on a sub-picosecond timescale.We demonstrate that THz radiation changes its polarity with reversal of the ma...Using THz emission spectroscopy,we investigate the elementary spin dynamics in ferromagnetic single-layer Fe on a sub-picosecond timescale.We demonstrate that THz radiation changes its polarity with reversal of the magnetization applied by the external magnetic field.In addition,it is found that the sign of THz polarity excited from different sides is defined by the thickness of the Fe layer and Fe/dielectric interface.Based on the thickness and symmetry dependences of THz emission,we experimentally distinguish between the two major contributions:ultrafast demagnetization and the anomalous Hall effect.Our experimental results not only enrich understanding of THz electromagnetic generation induced by femtosecond laser pulses but also provide a practical way to access laser-induced ultrafast spin dynamics in magnetic structures.展开更多
Several rocksalt Sr4X3N (X = O, S, Se, and Te) are predicted to be potential half-metallic ferromagnets free of transition-metal and rare-earth elements by performing the first-principles calculations. Then their ma...Several rocksalt Sr4X3N (X = O, S, Se, and Te) are predicted to be potential half-metallic ferromagnets free of transition-metal and rare-earth elements by performing the first-principles calculations. Then their magnetic properties, such as the half metallicity and the crystal-cell magnetic moments are investigated. The Sr4X3N possibly have higher Curie temperatures and have more stable half metallicity than the Sr4X3C. Their crystal-cell magnetic moments are all 1.00 μB. The crystal-cell magnetic moments and the half metallicity arise mainly from the N ions. The main mechanism is the strong covalent interaction leading to the sp2 hybridized orbitals in the Sr4X3N. Then two Sr-5s and three N-2p electrons enter into three sp2 hybridized orbitals. Among these five electrons, four electrons are paired and one is unpaired, so there are three spin-up electrons and two spin-down electrons in these sp2 hybridized orbitals.展开更多
Searching for one-dimensional(1D)nanostructure with ferromagnetic(FM)half-metallicity is of significance for the development of miniature spintronic devices.Here,based on the first-principles calculations,we propose t...Searching for one-dimensional(1D)nanostructure with ferromagnetic(FM)half-metallicity is of significance for the development of miniature spintronic devices.Here,based on the first-principles calculations,we propose that the 1D CrN nanostructure is a FM half-metal,which can generate the fully spin-polarized current.The ab initio molecular dynamic simulation and the phonon spectrum calculation demonstrate that the 1D CrN nanostructure is thermodynamically stable.The partially occupied Cr-d orbitals endow the nanostructure with FM half-metallicity,in which the half-metallic gap(?s)reaches up to 1.58 eV.The ferromagnetism in the nanostructure is attributed to the superexchange interaction between the magnetic Cr atoms,and a sizable magnetocrystalline anisotropy energy(MAE)is obtained.Moreover,the transverse stretching of nanostructure can effectively modulate?s and MAE,accompanied by the preservation of half-metallicity.A nanocable is designed by encapsulating the CrN nanostructure with a BN nanotube,and the intriguing magnetic and electronic properties of the nanostructure are retained.These novel characteristics render the 1D CrN nanostructure as a compelling candidate for exploiting high-performance spintronic devices.展开更多
Repetitive transcranial magnetic stimulation has been increasingly studied in different neurological diseases,and although most studies focus on its effects on neuronal cells,the contribution of nonneuronal cells to t...Repetitive transcranial magnetic stimulation has been increasingly studied in different neurological diseases,and although most studies focus on its effects on neuronal cells,the contribution of nonneuronal cells to the improvement trigge red by repetitive transcranial magnetic stimulation in these diseases has been increasingly suggested.To systematically review the effects of repetitive magnetic stimulation on non-neuronal cells two online databases.Web of Science and PubMed were searched fo r the effects of high-frequency-repetitive transcranial magnetic stimulation,low-frequencyrepetitive transcranial magnetic stimulation,intermittent theta-bu rst stimulation,continuous thetaburst stimulation,or repetitive magnetic stimulation on non-neuronal cells in models of disease and in unlesioned animals or cells.A total of 52 studies were included.The protocol more frequently used was high-frequency-repetitive magnetic stimulation,and in models of disease,most studies report that high-frequency-repetitive magnetic stimulation led to a decrease in astrocyte and mic roglial reactivity,a decrease in the release of pro-inflammatory cyto kines,and an increase of oligodendrocyte proliferation.The trend towards decreased microglial and astrocyte reactivity as well as increased oligodendrocyte proliferation occurred with intermittent theta-burst stimulation and continuous theta-burst stimulation.Few papers analyzed the low-frequency-repetitive transcranial magnetic stimulation protocol,and the parameters evaluated were restricted to the study of astrocyte reactivity and release of pro-inflammatory cytokines,repo rting the absence of effects on these paramete rs.In what concerns the use of magnetic stimulation in unlesioned animals or cells,most articles on all four types of stimulation reported a lack of effects.It is also important to point out that the studies were developed mostly in male rodents,not evaluating possible diffe rential effects of repetitive transcranial magnetic stimulation between sexes.This systematic review supports that thro ugh modulation of glial cells repetitive magnetic stimulation contributes to the neuroprotection or repair in various neurological disease models.Howeve r,it should be noted that there are still few articles focusing on the impact of repetitive magnetic stimulation on non-neuronal cells and most studies did not perform in-depth analyses of the effects,emphasizing the need for more studies in this field.展开更多
The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection process.To explore electron acceleration in a 3D magnetic null topol...The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection process.To explore electron acceleration in a 3D magnetic null topology,we constructed a pair of 3D magnetic nulls in the PKU Plasma Test(PPT)device and observed acceleration of electrons near magnetic nulls.This study measured the plasma floating potential and ion density profiles around the 3D magnetic null.The potential wells near nulls may be related to the energy variations of electrons,so we measured the electron distribution functions(EDFs)at different spatial positions.The axial variation of EDF shows that the electrons deviate from the Maxwell distribution near magnetic nulls.With scanning probes that can directionally measure and theoretically analyze based on curve fitting,the variations of EDFs are linked to the changes of plasma potential under 3D magnetic null topology.The kinetic energy of electrons accelerated by the electric field is 6 eV(v_(e)~7v_(Alfvén-e))and the scale of the region where accelerating electrons exist is in the order of serval electron skin depths.展开更多
Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infue...Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder.展开更多
BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diff...BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diffusion models for liver fibrosis in one cohort.AIM To evaluate the clinical potential of six diffusion-weighted models in liver fibrosis staging and compare their diagnostic performances.METHODS This prospective study enrolled 59 patients suspected of liver disease and scheduled for liver biopsy and 17 healthy participants.All participants underwent multi-b value DWI.The main DWI-derived parameters included Mono-apparent diffusion coefficient(ADC)from mono-exponential DWI,intravoxel incoherent motion model-derived true diffusion coefficient(IVIM-D),diffusion kurtosis imaging-derived apparent diffusivity(DKI-MD),stretched exponential model-derived distributed diffusion coefficient(SEM-DDC),fractional order calculus(FROC)model-derived diffusion coefficient(FROC-D)and FROC model-derived microstructural quantity(FROC-μ),and continuous-time random-walk(CTRW)model-derived anomalous diffusion coefficient(CTRW-D)and CTRW model-derived temporal diffusion heterogeneity index(CTRW-α).The correlations between DWI-derived parameters and fibrosis stages and the parameters’diagnostic efficacy in detecting significant fibrosis(SF)were assessed and compared.RESULTS CTRW-D(r=-0.356),CTRW-α(r=-0.297),DKI-MD(r=-0.297),FROC-D(r=-0.350),FROC-μ(r=-0.321),IVIM-D(r=-0.251),Mono-ADC(r=-0.362),and SEM-DDC(r=-0.263)were significantly correlated with fibrosis stages.The areas under the ROC curves(AUCs)of the combined index of the six models for distinguishing SF(0.697-0.747)were higher than each of the parameters alone(0.524-0.719).The DWI models’ability to detect SF was similar.The combined index of CTRW model parameters had the highest AUC(0.747).CONCLUSION The DWI models were similarly valuable in distinguishing SF in patients with liver disease.The combined index of CTRW parameters had the highest AUC.展开更多
BACKGROUND Perineural invasion(PNI)has been used as an important pathological indicator and independent prognostic factor for patients with rectal cancer(RC).Preoperative prediction of PNI status is helpful for indivi...BACKGROUND Perineural invasion(PNI)has been used as an important pathological indicator and independent prognostic factor for patients with rectal cancer(RC).Preoperative prediction of PNI status is helpful for individualized treatment of RC.Recently,several radiomics studies have been used to predict the PNI status in RC,demonstrating a good predictive effect,but the results lacked generalizability.The preoperative prediction of PNI status is still challenging and needs further study.AIM To establish and validate an optimal radiomics model for predicting PNI status preoperatively in RC patients.METHODS This retrospective study enrolled 244 postoperative patients with pathologically confirmed RC from two independent centers.The patients underwent preoperative high-resolution magnetic resonance imaging(MRI)between May 2019 and August 2022.Quantitative radiomics features were extracted and selected from oblique axial T2-weighted imaging(T2WI)and contrast-enhanced T1WI(T1CE)sequences.The radiomics signatures were constructed using logistic regression analysis and the predictive potential of various sequences was compared(T2WI,T1CE and T2WI+T1CE fusion sequences).A clinical-radiomics(CR)model was established by combining the radiomics features and clinical risk factors.The internal and external validation groups were used to validate the proposed models.The area under the receiver operating characteristic curve(AUC),DeLong test,net reclassification improvement(NRI),integrated discrimination improvement(IDI),calibration curve,and decision curve analysis(DCA)were used to evaluate the model performance.RESULTS Among the radiomics models,the T2WI+T1CE fusion sequences model showed the best predictive performance,in the training and internal validation groups,the AUCs of the fusion sequence model were 0.839[95%confidence interval(CI):0.757-0.921]and 0.787(95%CI:0.650-0.923),which were higher than those of the T2WI and T1CE sequence models.The CR model constructed by combining clinical risk factors had the best predictive performance.In the training and internal and external validation groups,the AUCs of the CR model were 0.889(95%CI:0.824-0.954),0.889(95%CI:0.803-0.976)and 0.894(95%CI:0.814-0.974).Delong test,NRI,and IDI showed that the CR model had significant differences from other models(P<0.05).Calibration curves demonstrated good agreement,and DCA revealed significant benefits of the CR model.CONCLUSION The CR model based on preoperative MRI radiomics features and clinical risk factors can preoperatively predict the PNI status of RC noninvasively,which facilitates individualized treatment of RC patients.展开更多
We perform a first-principles study of electronic structure and magnetism of C-doped zinc-blende ZnO using the full-potential linearized augmented plane wave method. Results show that C-doped zinc-blende ZnO exhibits ...We perform a first-principles study of electronic structure and magnetism of C-doped zinc-blende ZnO using the full-potential linearized augmented plane wave method. Results show that C-doped zinc-blende ZnO exhibits half-metallic ferromagnetism with a stable ferromagnetic ground state. The calculated magnetic moment of the 32-atom supercell containing one C dopant is 2.00 μ B , and the C dopant contributes most. The calculated low formation energy suggests that C-doped zinc-blende ZnO is energetically stable. The hole-mediated double exchange mechanism can be used to explain the ferromagnetism in C-doped zinc-blende ZnO.展开更多
The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magne...The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.展开更多
To determine the cause(s)of perturbations seen in dayside equatorial ground magnetograms,we conducted a systematic survey of simultaneous ground-based and geosynchronous satellite-based observations during the 90-day ...To determine the cause(s)of perturbations seen in dayside equatorial ground magnetograms,we conducted a systematic survey of simultaneous ground-based and geosynchronous satellite-based observations during the 90-day period from December 1,2020 to February 28,2021.We examined Huancayo ground magnetometer observations from 14:00:00 to 20:00:00 UT each day,during which Huancayo passed through local noon.From those data we chose perturbation events selected on the basis of large(>20 nT)event amplitude and classified the selected events as responding primarily to solar wind pressure,or to variations in the north/south component of the interplanetary magnetic field(IMF Bz),or perhaps in part to both.The results show that an equivalent number of events were identified for each model during this 90-day period.Variations in the lagged solar wind dynamic pressure routinely correspond to nearly simultaneous sudden impulses recorded at both geosynchronous orbit and on the ground.Variations in IMF Bz produce erosion signatures at geosynchronous orbit and can correspond to ground events if lag times for reconnection to enhance convection in the magnetosphere are taken into account.展开更多
AIM:To investigate the difference of medial rectus(MR)and lateral rectus(LR)between acute acquired concomitant esotropia(AACE)and the healthy controls(HCs)detected by magnetic resonance imaging(MRI).METHODS:A case-con...AIM:To investigate the difference of medial rectus(MR)and lateral rectus(LR)between acute acquired concomitant esotropia(AACE)and the healthy controls(HCs)detected by magnetic resonance imaging(MRI).METHODS:A case-control study.Eighteen subjects with AACE and eighteen HCs were enrolled.MRI scanning data were conducted in target-controlled central gaze with a 3-Tesla magnetic resonance scanner.Extraocular muscles(EOMs)were scanned in contiguous image planes 2-mm thick spanning the EOM origins to the globe equator.To form posterior partial volumes(PPVs),the LR and MR cross-sections in the image planes 8,10,12,and 14 mm posterior to the globe were summed and multiplied by the 2-mm slice thickness.The data were classified according to the right eye,left eye,dominant eye,and non-dominant eye,and the differences in mean cross-sectional area,maximum cross-sectional area,and PPVs of the MR and LR muscle in the AACE group and HCs group were compared under the above classifications respectively.RESULTS:There were no significant differences between the two groups of demographic characteristics.The mean cross-sectional area of the LR muscle was significantly greater in the AACE group than that in the HCs group in the non-dominant eyes(P=0.028).The maximum cross-sectional area of the LR muscle both in the dominant and non-dominant eye of the AACE group was significantly greater than the HCs group(P=0.009,P=0.016).For the dominant eye,the PPVs of the LR muscle were significantly greater in the AACE than that in the HCs group(P=0.013),but not in the MR muscle(P=0.698).CONCLUSION:The size and volume of muscles dominant eyes of AACE subjects change significantly to overcome binocular diplopia.The LR muscle become larger to compensate for the enhanced convergence in the AACE.展开更多
The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, a...The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.展开更多
BACKGROUND High-grade pancreatic intraepithelial neoplasia(PanIN)exhibits no mass and is not detected by any examination modalities.However,it can be diagnosed by pancreatic juice cytology from indirect findings.Most ...BACKGROUND High-grade pancreatic intraepithelial neoplasia(PanIN)exhibits no mass and is not detected by any examination modalities.However,it can be diagnosed by pancreatic juice cytology from indirect findings.Most previous cases were diagnosed based on findings of a focal stricture of the main pancreatic duct(MPD)and caudal MPD dilatation and subsequent pancreatic juice cytology using endoscopic retrograde cholangiopancreatography(ERCP).We experienced a case of high-grade PanIN with an unclear MPD over a 20-mm range,but without caudal MPD dilatation on magnetic resonance cholangiopancreatography(MRCP).CASE SUMMARY A 60-year-old female patient underwent computed tomography for a follow-up of uterine cancer post-excision,which revealed pancreatic cysts.MRCP revealed an unclear MPD of the pancreatic body at a 20-mm length without caudal MPD dilatation.Thus,course observation was performed.After 24 mo,MRCP revealed an increased caudal MPD caliber and a larger pancreatic cyst.We performed ERCP and detected atypical cells suspected of adenocarcinoma by serial pancreatic juice aspiration cytology examination.We performed a distal pancreatectomy and obtained a histopathological diagnosis of high-grade PanIN.Pancreatic parenchyma invasion was not observed,and curative resection was achieved.CONCLUSION High-grade Pan-IN may cause MPD narrowing in a long range without caudal MPD dilatation.展开更多
BACKGROUND Fecal incontinence(FI)is an involuntary passage of fecal matter which can have a significant impact on a patient’s quality of life.Many modalities of treatment exist for FI.Sacral nerve stimulation is a we...BACKGROUND Fecal incontinence(FI)is an involuntary passage of fecal matter which can have a significant impact on a patient’s quality of life.Many modalities of treatment exist for FI.Sacral nerve stimulation is a well-established treatment for FI.Given the increased need of magnetic resonance imaging(MRI)for diagnostics,the In-terStim which was previously used in sacral nerve stimulation was limited by MRI incompatibility.Medtronic MRI-compatible InterStim was approved by the United States Food and Drug Administration in August 2020 and has been widely used.AIM To evaluate the efficacy,outcomes and complications of the MRI-compatible InterStim.METHODS Data of patients who underwent MRI-compatible Medtronic InterStim placement at UPMC Williamsport,University of Minnesota,Advocate Lutheran General Hospital,and University of Wisconsin-Madison was pooled and analyzed.Patient demographics,clinical features,surgical techniques,complications,and outcomes were analyzed.Strengthening the Reporting of Observational studies in Epidemiology(STROBE)cross-sectional reporting guidelines were used.RESULTS Seventy-three patients had the InterStim implanted.The mean age was 63.29±12.2 years.Fifty-seven(78.1%)patients were females and forty-two(57.5%)patients had diabetes.In addition to incontinence,overlapping symptoms included diarrhea(23.3%),fecal urgency(58.9%),and urinary incontinence(28.8%).Fifteen(20.5%)patients underwent Peripheral Nerve Evaluation before proceeding to definite implant placement.Thirty-two(43.8%)patients underwent rechargeable InterStim placement.Three(4.1%)patients needed removal of the implant.Migration of the external lead connection was observed in 7(9.6%)patients after the stage I procedure.The explanation for one patient was due to infection.Seven(9.6%)patients had other complications like nerve pain,hematoma,infection,lead fracture,and bleeding.The mean follow-up was 6.62±3.5 mo.Sixty-eight(93.2%)patients reported significant improvement of symptoms on follow-up evaluation.CONCLUSION This study shows promising results with significant symptom improvement,good efficacy and good patient outcomes with low complication rates while using MRI compatible InterStim for FI.Further long-term follow-up and future studies with a larger patient population is recommended.展开更多
First-principles spin-polarized density functional theory (DFT) investigations of the structural, electronic, magnetic, and thermodynamics characteristics of the half-Heusler, CoMnTe and RuMnTe compounds are carried...First-principles spin-polarized density functional theory (DFT) investigations of the structural, electronic, magnetic, and thermodynamics characteristics of the half-Heusler, CoMnTe and RuMnTe compounds are carried out. Calculations are accomplished within a state of the art full-potential (FP) linearized (L) augmented plane wave plus a local orbital (APW + lo) computational approach framed within DFT. The generalized gradient approximation (GGA) parameterized by Perdew, Burke, and Ernzerhof (PBE) is implemented as an exchange correlation functional as a part of the total energy calculation. From the analysis of the calculated electronic band structure as well as the density of states for both compounds, a strong hybridization between d states of the higher valent transition metal (TM) atoms (Co, Ru) and lower valent TM atoms of (Mn) is observed. Furthermore, total and partial density of states (PDOS) of the ground state and the results of spin magnetic moments reveal that these compounds are both stable and ideal half-metallic ferromagnetic. The effects of the unit cell volume on the magnetic properties and half-metaliicity are crucial. It is worth noting that our computed results of the total spin magnetic moments, for CoMnTe equal to 4 ~tB and 3 p-B per unit cell for RuMnTe, nicely follow the rule μ2tot = Zt - 18. Using the quasi-harmonic Debye model, which considers the phononic effects, the effecs of pressure P and temperature T on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature, and heat capacity for these compounds are investigated for the first time.展开更多
基金the National Natural Science Foundation of China(51303083)the National Natural Science Foundation of China for Excellent Young Scholars(51922050)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20191293)the Fundamental Research Funds for the Central Universities(30920021123)。
文摘Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a big challenge.Herein,a three-dimensional(3D)hierarchical W_(18)O_(49)/WTe_(2) hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO_(3).The light absorption towards near-infrared spectral region and CO_(2) adsorption are enhanced by the formation of half-metal WTe_(2) and the unique hierarchical hollow architecture.Combining with the generation of oxygen vacancy with strengthened CO_(2) capture,the photothermal effect on the samples can be sufficiently exploited for activating the CO_(2) molecules.In particular,the close contact between W_(18)O_(49)and WTe_(2) largely promotes the photoinduced charge separation and mass transfer,and thus the~*CHO intermediate formation and fixedness are facilitated.As a result,the C-C coupling can be evoked between tungsten and tellurium atoms on WTe_(2).The ethylene production by optimized W_(18)O_(49)/WTe_(2) reaches 147.6μmol g^(-1)with the selectivity of 80%.The in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C-C coupling.The half-metallic WTe_(2) cocatalyst proposes a new approach for efficient CO_(2) conversion with solar energy,and may especially create a new platform for the generation of multi-carbon products.
基金the National Key R&D Program of China(Grant No.2019YFA0308603)the National Natural Science Foundation of China(Grant No.11934020)。
文摘By using first-principles electronic structure calculations,we predict a new two-dimensional half-metallic ferromagnet(2DHMF)with distorted square structure,i.e.,the LiCrTe_(2) monolayer.The results show that the LiCrTe_(2) monolayer is dynamically,thermally,and mechanically stable,and takes a large in-plane magnetic anisotropy,a wide spin gap,a large magnetization,and a very high Curie temperature.Under a biaxial strain ranging from-5% to+5%,the ferromagnetism,half-metallicity,and high Curie temperature are maintained well.Both tensile and compressive strains can significantly increase the magnitude of the magnetocrystalline anisotropy energy(MAE)and a transition from in-plane easy-x(y)-axis to out-of-plane easy-z-axis occurs when the compressive strain exceeds 1%.Our systematic study of the LiCrTe_(2) monolayer enables its promising applications in spintronics.
基金ACKNOWLEDGMENTS This work was supported by the Chongqing Natural Science Foundation (No.CSTC2007BB4391 and No.CSTC2008BB4083) and the Chongqing Science and Technology Foundation (No.kj060515 and No.kj080518)
文摘The geometrical structures of wurtzite CrX (X=As, Sb, O, Se, and Te) were optimized, then their electric and magnetic properties were investigated by the first-principle calculations within the generalized gradient approximation for the exchange-correlation functional based on the density functional theory. These Cr-phosphides and Cr-sulphides were predicted to be half-metallic ferromagnets whose spin-polarization at the Fermi level is absolutely 100%. The molecular magnetic moments of Cr-phosphides and Cr-sulphides are 3.00 and 4.00 μB, which arise mainly from Cr-ions, respectively. There is ferromagnetic coupling in both Cr- phosphides and Cr-sulphides. The Curie temperatures of Cr-sulphides and Cr-phosphides are high. The electronic structures of Cr-ions are a1g^2↑↓t1u^4↑↓t1u^1↑↓eg^2↑↓in Cr-phosphides and a1g^2↑↓t1u^4↑↓t1u^1↑t2g^3↑in Cr-sulphides, respectively.
基金ACKNOWLEDGMENTS This work was supported by the the National Natural Science Foundation of China (No.10974048) and the Excellent Middle Age and Youth People Science and Technology Creative Team Foundation of the Educational Department of the Hubei Province (No.T200805).
文摘The electronic structure and half-metallicity of molecule-based ferromagnet Cr[N(CN)2]2 have been investigated using first-principles with generalized gradient approximation. The total energy, spin-polarized electronic band structure, density of states (DOSs) and spin magnetic moments were all calculated. The calculations reveal that the compound Cr[N(CN)2]2 is a really half-metallic ferromagnet with a integral magnetic moment of 2.0000 μB per molecule in the optimized lattice constant. Based on the spin distribution and the DOS, it is found that the total magnetic moment is mainly from the Cr2+ with relative small contribution from C and N atoms. The sensitivity of the half-metallicity to small change in lattice constant is also discussed.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFF0719200 and 2022YFA1404004)the National Natural Science Foundation of China(Grant Nos.61988102,62322115,61975110,and 62335012)+3 种基金the 111 Project(Grant No.D18014)the Key Project supported by Science and Technology Commission Shanghai Municipality(Grant No.YDZX20193100004960)Science and Technology Commission of Shanghai Municipality(Grant No.22JC1400200)General Administration of Customs People’s Republic of China(Grant No.2019HK006)。
文摘Using THz emission spectroscopy,we investigate the elementary spin dynamics in ferromagnetic single-layer Fe on a sub-picosecond timescale.We demonstrate that THz radiation changes its polarity with reversal of the magnetization applied by the external magnetic field.In addition,it is found that the sign of THz polarity excited from different sides is defined by the thickness of the Fe layer and Fe/dielectric interface.Based on the thickness and symmetry dependences of THz emission,we experimentally distinguish between the two major contributions:ultrafast demagnetization and the anomalous Hall effect.Our experimental results not only enrich understanding of THz electromagnetic generation induced by femtosecond laser pulses but also provide a practical way to access laser-induced ultrafast spin dynamics in magnetic structures.
基金Project supported by Chongqing Natural Science Foundation,China (Grant Nos.CSCT2010BB4405 and CSTC2008BB4083)the Doctoral Foundation of Chongqing University of Posts and Telecommunications,China(Grant No.A2008-63)
文摘Several rocksalt Sr4X3N (X = O, S, Se, and Te) are predicted to be potential half-metallic ferromagnets free of transition-metal and rare-earth elements by performing the first-principles calculations. Then their magnetic properties, such as the half metallicity and the crystal-cell magnetic moments are investigated. The Sr4X3N possibly have higher Curie temperatures and have more stable half metallicity than the Sr4X3C. Their crystal-cell magnetic moments are all 1.00 μB. The crystal-cell magnetic moments and the half metallicity arise mainly from the N ions. The main mechanism is the strong covalent interaction leading to the sp2 hybridized orbitals in the Sr4X3N. Then two Sr-5s and three N-2p electrons enter into three sp2 hybridized orbitals. Among these five electrons, four electrons are paired and one is unpaired, so there are three spin-up electrons and two spin-down electrons in these sp2 hybridized orbitals.
基金the National Natural Science Foundation of China(Grant Nos.12004137,62071200,and 12104236)Shandong Provincial Natural Science Foundation of China(Grant Nos.ZR2020QA052,ZR2020ZD28,ZR2021MA040,and ZR2021MA060).
文摘Searching for one-dimensional(1D)nanostructure with ferromagnetic(FM)half-metallicity is of significance for the development of miniature spintronic devices.Here,based on the first-principles calculations,we propose that the 1D CrN nanostructure is a FM half-metal,which can generate the fully spin-polarized current.The ab initio molecular dynamic simulation and the phonon spectrum calculation demonstrate that the 1D CrN nanostructure is thermodynamically stable.The partially occupied Cr-d orbitals endow the nanostructure with FM half-metallicity,in which the half-metallic gap(?s)reaches up to 1.58 eV.The ferromagnetism in the nanostructure is attributed to the superexchange interaction between the magnetic Cr atoms,and a sizable magnetocrystalline anisotropy energy(MAE)is obtained.Moreover,the transverse stretching of nanostructure can effectively modulate?s and MAE,accompanied by the preservation of half-metallicity.A nanocable is designed by encapsulating the CrN nanostructure with a BN nanotube,and the intriguing magnetic and electronic properties of the nanostructure are retained.These novel characteristics render the 1D CrN nanostructure as a compelling candidate for exploiting high-performance spintronic devices.
基金the scope of the CICS-UBI projects UIDP/Multi/00709/2019,UIDB/Multi/00709/2019,UIDP/00709/2020,UIDB/00709/2020,financed by national funds through the Portuguese Foundation for Science and Technology/MCTESby funds to the PPBI-Portuguese Platform of Bio Imaging through the Project POCI-01-0145-FEDER-022122(to GB,MVP,NP)supported by a grant from the Portuguese Foundation for Science and Technology/MCTES(2021.07854.BD)(to IS)。
文摘Repetitive transcranial magnetic stimulation has been increasingly studied in different neurological diseases,and although most studies focus on its effects on neuronal cells,the contribution of nonneuronal cells to the improvement trigge red by repetitive transcranial magnetic stimulation in these diseases has been increasingly suggested.To systematically review the effects of repetitive magnetic stimulation on non-neuronal cells two online databases.Web of Science and PubMed were searched fo r the effects of high-frequency-repetitive transcranial magnetic stimulation,low-frequencyrepetitive transcranial magnetic stimulation,intermittent theta-bu rst stimulation,continuous thetaburst stimulation,or repetitive magnetic stimulation on non-neuronal cells in models of disease and in unlesioned animals or cells.A total of 52 studies were included.The protocol more frequently used was high-frequency-repetitive magnetic stimulation,and in models of disease,most studies report that high-frequency-repetitive magnetic stimulation led to a decrease in astrocyte and mic roglial reactivity,a decrease in the release of pro-inflammatory cyto kines,and an increase of oligodendrocyte proliferation.The trend towards decreased microglial and astrocyte reactivity as well as increased oligodendrocyte proliferation occurred with intermittent theta-burst stimulation and continuous theta-burst stimulation.Few papers analyzed the low-frequency-repetitive transcranial magnetic stimulation protocol,and the parameters evaluated were restricted to the study of astrocyte reactivity and release of pro-inflammatory cytokines,repo rting the absence of effects on these paramete rs.In what concerns the use of magnetic stimulation in unlesioned animals or cells,most articles on all four types of stimulation reported a lack of effects.It is also important to point out that the studies were developed mostly in male rodents,not evaluating possible diffe rential effects of repetitive transcranial magnetic stimulation between sexes.This systematic review supports that thro ugh modulation of glial cells repetitive magnetic stimulation contributes to the neuroprotection or repair in various neurological disease models.Howeve r,it should be noted that there are still few articles focusing on the impact of repetitive magnetic stimulation on non-neuronal cells and most studies did not perform in-depth analyses of the effects,emphasizing the need for more studies in this field.
基金supported by National Natural Science Foundation of China(No.11975038)the National Key Research and Development Program of China(No.2022YFA1604600)。
文摘The acceleration of electrons near three-dimensional(3D)magnetic nulls is crucial to the energy conversion mechanism in the 3D magnetic reconnection process.To explore electron acceleration in a 3D magnetic null topology,we constructed a pair of 3D magnetic nulls in the PKU Plasma Test(PPT)device and observed acceleration of electrons near magnetic nulls.This study measured the plasma floating potential and ion density profiles around the 3D magnetic null.The potential wells near nulls may be related to the energy variations of electrons,so we measured the electron distribution functions(EDFs)at different spatial positions.The axial variation of EDF shows that the electrons deviate from the Maxwell distribution near magnetic nulls.With scanning probes that can directionally measure and theoretically analyze based on curve fitting,the variations of EDFs are linked to the changes of plasma potential under 3D magnetic null topology.The kinetic energy of electrons accelerated by the electric field is 6 eV(v_(e)~7v_(Alfvén-e))and the scale of the region where accelerating electrons exist is in the order of serval electron skin depths.
基金supported by the National Key R&D Program of China(Grant No.2022YFB4600300)the National Natural Science Foundation of China(No.U22A20189,52175364)the China Scholarship Council(Grant No.202206290134)。
文摘Nd-Fe-B permanent magnets play a crucial role in energy conversion and electronic devices.The essential magnetic properties of Nd-Fe-B magnets,particularly coercivity and remanent magnetization,are significantly infuenced by the phase characteristics and microstructure.In this work,Nd-Fe-B magnets were manufactured using vacuum induction melting(VIM),laser directed energy deposition(LDED)and laser powder bed fusion(LPBF)technologies.Themicrostructure evolution and phase selection of Nd-Fe-B magnets were then clarified in detail.The results indicated that the solidification velocity(V)and cooling rate(R)are key factors in the phase selection.In terms of the VIM-casting Nd-Fe-B magnet,a large volume fraction of theα-Fe soft magnetic phase(39.7 vol.%)and Nd2Fe17Bxmetastable phase(34.7 vol.%)areformed due to the low R(2.3×10-1?C s-1),whereas only a minor fraction of the Nd2Fe14B hard magnetic phase(5.15 vol.%)is presented.For the LDED-processed Nd-Fe-B deposit,although the Nd2Fe14B hard magnetic phase also had a low value(3.4 vol.%)as the values of V(<10-2m s-1)and R(5.06×103?C s-1)increased,part of theα-Fe soft magnetic phase(31.7vol.%)is suppressed,and a higher volume of Nd2Fe17Bxmetastable phases(47.5 vol.%)areformed.As a result,both the VIM-casting and LDED-processed Nd-Fe-B deposits exhibited poor magnetic properties.In contrast,employing the high values of V(>10-2m s-1)and R(1.45×106?C s-1)in the LPBF process resulted in the substantial formation of the Nd2Fe14B hard magnetic phase(55.8 vol.%)directly from the liquid,while theα-Fe soft magnetic phase and Nd2Fe17Bxmetastable phase precipitation are suppressed in the LPBF-processed Nd-Fe-B magnet.Additionally,crystallographic texture analysis reveals that the LPBF-processedNd-Fe-B magnets exhibit isotropic magnetic characteristics.Consequently,the LPBF-processed Nd-Fe-B deposit,exhibiting a coercivity of 656 k A m-1,remanence of 0.79 T and maximum energy product of 71.5 k J m-3,achieved an acceptable magnetic performance,comparable to other additive manufacturing processed Nd-Fe-B magnets from MQP(Nd-lean)Nd-Fe-Bpowder.
基金the Cuiying Scientific and Technological Innovation Program of Lanzhou University Second Hospital,NO.CY2021-QNB09the Science and Technology Project of Gansu Province,NO.21JR11RA122+1 种基金Department of Education of Gansu Province:Innovation Fund Project,NO.2022B-056Gansu Province Clinical Research Center for Functional and Molecular Imaging,NO.21JR7RA438.
文摘BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diffusion models for liver fibrosis in one cohort.AIM To evaluate the clinical potential of six diffusion-weighted models in liver fibrosis staging and compare their diagnostic performances.METHODS This prospective study enrolled 59 patients suspected of liver disease and scheduled for liver biopsy and 17 healthy participants.All participants underwent multi-b value DWI.The main DWI-derived parameters included Mono-apparent diffusion coefficient(ADC)from mono-exponential DWI,intravoxel incoherent motion model-derived true diffusion coefficient(IVIM-D),diffusion kurtosis imaging-derived apparent diffusivity(DKI-MD),stretched exponential model-derived distributed diffusion coefficient(SEM-DDC),fractional order calculus(FROC)model-derived diffusion coefficient(FROC-D)and FROC model-derived microstructural quantity(FROC-μ),and continuous-time random-walk(CTRW)model-derived anomalous diffusion coefficient(CTRW-D)and CTRW model-derived temporal diffusion heterogeneity index(CTRW-α).The correlations between DWI-derived parameters and fibrosis stages and the parameters’diagnostic efficacy in detecting significant fibrosis(SF)were assessed and compared.RESULTS CTRW-D(r=-0.356),CTRW-α(r=-0.297),DKI-MD(r=-0.297),FROC-D(r=-0.350),FROC-μ(r=-0.321),IVIM-D(r=-0.251),Mono-ADC(r=-0.362),and SEM-DDC(r=-0.263)were significantly correlated with fibrosis stages.The areas under the ROC curves(AUCs)of the combined index of the six models for distinguishing SF(0.697-0.747)were higher than each of the parameters alone(0.524-0.719).The DWI models’ability to detect SF was similar.The combined index of CTRW model parameters had the highest AUC(0.747).CONCLUSION The DWI models were similarly valuable in distinguishing SF in patients with liver disease.The combined index of CTRW parameters had the highest AUC.
文摘BACKGROUND Perineural invasion(PNI)has been used as an important pathological indicator and independent prognostic factor for patients with rectal cancer(RC).Preoperative prediction of PNI status is helpful for individualized treatment of RC.Recently,several radiomics studies have been used to predict the PNI status in RC,demonstrating a good predictive effect,but the results lacked generalizability.The preoperative prediction of PNI status is still challenging and needs further study.AIM To establish and validate an optimal radiomics model for predicting PNI status preoperatively in RC patients.METHODS This retrospective study enrolled 244 postoperative patients with pathologically confirmed RC from two independent centers.The patients underwent preoperative high-resolution magnetic resonance imaging(MRI)between May 2019 and August 2022.Quantitative radiomics features were extracted and selected from oblique axial T2-weighted imaging(T2WI)and contrast-enhanced T1WI(T1CE)sequences.The radiomics signatures were constructed using logistic regression analysis and the predictive potential of various sequences was compared(T2WI,T1CE and T2WI+T1CE fusion sequences).A clinical-radiomics(CR)model was established by combining the radiomics features and clinical risk factors.The internal and external validation groups were used to validate the proposed models.The area under the receiver operating characteristic curve(AUC),DeLong test,net reclassification improvement(NRI),integrated discrimination improvement(IDI),calibration curve,and decision curve analysis(DCA)were used to evaluate the model performance.RESULTS Among the radiomics models,the T2WI+T1CE fusion sequences model showed the best predictive performance,in the training and internal validation groups,the AUCs of the fusion sequence model were 0.839[95%confidence interval(CI):0.757-0.921]and 0.787(95%CI:0.650-0.923),which were higher than those of the T2WI and T1CE sequence models.The CR model constructed by combining clinical risk factors had the best predictive performance.In the training and internal and external validation groups,the AUCs of the CR model were 0.889(95%CI:0.824-0.954),0.889(95%CI:0.803-0.976)and 0.894(95%CI:0.814-0.974).Delong test,NRI,and IDI showed that the CR model had significant differences from other models(P<0.05).Calibration curves demonstrated good agreement,and DCA revealed significant benefits of the CR model.CONCLUSION The CR model based on preoperative MRI radiomics features and clinical risk factors can preoperatively predict the PNI status of RC noninvasively,which facilitates individualized treatment of RC patients.
基金Project supported by the National Natural Science Foundation of China (Grants Nos. 11004066 and 11074081)the Research Foundation for the Doctoral Program of Higher Education of China (Grant Nos. 20100142120080 and 20090142110063)
文摘We perform a first-principles study of electronic structure and magnetism of C-doped zinc-blende ZnO using the full-potential linearized augmented plane wave method. Results show that C-doped zinc-blende ZnO exhibits half-metallic ferromagnetism with a stable ferromagnetic ground state. The calculated magnetic moment of the 32-atom supercell containing one C dopant is 2.00 μ B , and the C dopant contributes most. The calculated low formation energy suggests that C-doped zinc-blende ZnO is energetically stable. The hole-mediated double exchange mechanism can be used to explain the ferromagnetism in C-doped zinc-blende ZnO.
基金support from the UK Space Agency under Grant Number ST/T002964/1partly supported by the International Space Science Institute(ISSI)in Bern,through ISSI International Team Project Number 523(“Imaging the Invisible:Unveiling the Global Structure of Earth’s Dynamic Magnetosphere”)。
文摘The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.
文摘To determine the cause(s)of perturbations seen in dayside equatorial ground magnetograms,we conducted a systematic survey of simultaneous ground-based and geosynchronous satellite-based observations during the 90-day period from December 1,2020 to February 28,2021.We examined Huancayo ground magnetometer observations from 14:00:00 to 20:00:00 UT each day,during which Huancayo passed through local noon.From those data we chose perturbation events selected on the basis of large(>20 nT)event amplitude and classified the selected events as responding primarily to solar wind pressure,or to variations in the north/south component of the interplanetary magnetic field(IMF Bz),or perhaps in part to both.The results show that an equivalent number of events were identified for each model during this 90-day period.Variations in the lagged solar wind dynamic pressure routinely correspond to nearly simultaneous sudden impulses recorded at both geosynchronous orbit and on the ground.Variations in IMF Bz produce erosion signatures at geosynchronous orbit and can correspond to ground events if lag times for reconnection to enhance convection in the magnetosphere are taken into account.
基金Supported by National Natural Science Foundation of China(No.82070998)Young Scientists Fund of the National Natural Science Foundation of China(No.82101174)+3 种基金Program of Beijing Hospitals Authority(No.XMLX202103)Program of Beijing Municipal Science&Technology Commission(No.Z201100005520044)Capital Health Development Research Special Project(No.2022-1-2053)Beijing Hospitals Authority Youth Programme(No.QML20230205).
文摘AIM:To investigate the difference of medial rectus(MR)and lateral rectus(LR)between acute acquired concomitant esotropia(AACE)and the healthy controls(HCs)detected by magnetic resonance imaging(MRI).METHODS:A case-control study.Eighteen subjects with AACE and eighteen HCs were enrolled.MRI scanning data were conducted in target-controlled central gaze with a 3-Tesla magnetic resonance scanner.Extraocular muscles(EOMs)were scanned in contiguous image planes 2-mm thick spanning the EOM origins to the globe equator.To form posterior partial volumes(PPVs),the LR and MR cross-sections in the image planes 8,10,12,and 14 mm posterior to the globe were summed and multiplied by the 2-mm slice thickness.The data were classified according to the right eye,left eye,dominant eye,and non-dominant eye,and the differences in mean cross-sectional area,maximum cross-sectional area,and PPVs of the MR and LR muscle in the AACE group and HCs group were compared under the above classifications respectively.RESULTS:There were no significant differences between the two groups of demographic characteristics.The mean cross-sectional area of the LR muscle was significantly greater in the AACE group than that in the HCs group in the non-dominant eyes(P=0.028).The maximum cross-sectional area of the LR muscle both in the dominant and non-dominant eye of the AACE group was significantly greater than the HCs group(P=0.009,P=0.016).For the dominant eye,the PPVs of the LR muscle were significantly greater in the AACE than that in the HCs group(P=0.013),but not in the MR muscle(P=0.698).CONCLUSION:The size and volume of muscles dominant eyes of AACE subjects change significantly to overcome binocular diplopia.The LR muscle become larger to compensate for the enhanced convergence in the AACE.
基金Project supported by the DST-FIST Program for Higher Education Institutions of India(No. SR/FST/MS-I/2018/23(C))。
文摘The thermal examination of a non-integer-ordered mobile fin with a magnetism in the presence of a trihybrid nanofluid(Fe_3O_4-Au-Zn-blood) is carried out. Three types of nanoparticles, each having a different shape, are considered. These shapes include spherical(Fe_3O_4), cylindrical(Au), and platelet(Zn) configurations. The combination approach is utilized to evaluate the physical and thermal characteristics of the trihybrid and hybrid nanofluids, excluding the thermal conductivity and dynamic viscosity. These two properties are inferred by means of the interpolation method based on the volume fraction of nanoparticles. The governing equation is transformed into a dimensionless form, and the Adomian decomposition Sumudu transform method(ADSTM) is adopted to solve the conundrum of a moving fin immersed in a trihybrid nanofluid. The obtained results agree well with those numerical simulation results, indicating that this research is reliable. The influence of diverse factors on the thermal overview for varying noninteger values of γ is analyzed and presented in graphical representations. Furthermore, the fluctuations in the heat transfer concerning the pertinent parameters are studied. The results show that the heat flux in the presence of the combination of spherical, cylindrical, and platelet nanoparticles is higher than that in the presence of the combination of only spherical and cylindrical nanoparticles. The temperature at the fin tip increases by 0.705 759% when the value of the Peclet number increases by 400%, while decreases by 11.825 13% when the value of the Hartman number increases by 400%.
文摘BACKGROUND High-grade pancreatic intraepithelial neoplasia(PanIN)exhibits no mass and is not detected by any examination modalities.However,it can be diagnosed by pancreatic juice cytology from indirect findings.Most previous cases were diagnosed based on findings of a focal stricture of the main pancreatic duct(MPD)and caudal MPD dilatation and subsequent pancreatic juice cytology using endoscopic retrograde cholangiopancreatography(ERCP).We experienced a case of high-grade PanIN with an unclear MPD over a 20-mm range,but without caudal MPD dilatation on magnetic resonance cholangiopancreatography(MRCP).CASE SUMMARY A 60-year-old female patient underwent computed tomography for a follow-up of uterine cancer post-excision,which revealed pancreatic cysts.MRCP revealed an unclear MPD of the pancreatic body at a 20-mm length without caudal MPD dilatation.Thus,course observation was performed.After 24 mo,MRCP revealed an increased caudal MPD caliber and a larger pancreatic cyst.We performed ERCP and detected atypical cells suspected of adenocarcinoma by serial pancreatic juice aspiration cytology examination.We performed a distal pancreatectomy and obtained a histopathological diagnosis of high-grade PanIN.Pancreatic parenchyma invasion was not observed,and curative resection was achieved.CONCLUSION High-grade Pan-IN may cause MPD narrowing in a long range without caudal MPD dilatation.
文摘BACKGROUND Fecal incontinence(FI)is an involuntary passage of fecal matter which can have a significant impact on a patient’s quality of life.Many modalities of treatment exist for FI.Sacral nerve stimulation is a well-established treatment for FI.Given the increased need of magnetic resonance imaging(MRI)for diagnostics,the In-terStim which was previously used in sacral nerve stimulation was limited by MRI incompatibility.Medtronic MRI-compatible InterStim was approved by the United States Food and Drug Administration in August 2020 and has been widely used.AIM To evaluate the efficacy,outcomes and complications of the MRI-compatible InterStim.METHODS Data of patients who underwent MRI-compatible Medtronic InterStim placement at UPMC Williamsport,University of Minnesota,Advocate Lutheran General Hospital,and University of Wisconsin-Madison was pooled and analyzed.Patient demographics,clinical features,surgical techniques,complications,and outcomes were analyzed.Strengthening the Reporting of Observational studies in Epidemiology(STROBE)cross-sectional reporting guidelines were used.RESULTS Seventy-three patients had the InterStim implanted.The mean age was 63.29±12.2 years.Fifty-seven(78.1%)patients were females and forty-two(57.5%)patients had diabetes.In addition to incontinence,overlapping symptoms included diarrhea(23.3%),fecal urgency(58.9%),and urinary incontinence(28.8%).Fifteen(20.5%)patients underwent Peripheral Nerve Evaluation before proceeding to definite implant placement.Thirty-two(43.8%)patients underwent rechargeable InterStim placement.Three(4.1%)patients needed removal of the implant.Migration of the external lead connection was observed in 7(9.6%)patients after the stage I procedure.The explanation for one patient was due to infection.Seven(9.6%)patients had other complications like nerve pain,hematoma,infection,lead fracture,and bleeding.The mean follow-up was 6.62±3.5 mo.Sixty-eight(93.2%)patients reported significant improvement of symptoms on follow-up evaluation.CONCLUSION This study shows promising results with significant symptom improvement,good efficacy and good patient outcomes with low complication rates while using MRI compatible InterStim for FI.Further long-term follow-up and future studies with a larger patient population is recommended.
基金financial support provided by the Deanship of Scientific Research at King Saud University for funding this work through research group project No: RPG-VPP-088
文摘First-principles spin-polarized density functional theory (DFT) investigations of the structural, electronic, magnetic, and thermodynamics characteristics of the half-Heusler, CoMnTe and RuMnTe compounds are carried out. Calculations are accomplished within a state of the art full-potential (FP) linearized (L) augmented plane wave plus a local orbital (APW + lo) computational approach framed within DFT. The generalized gradient approximation (GGA) parameterized by Perdew, Burke, and Ernzerhof (PBE) is implemented as an exchange correlation functional as a part of the total energy calculation. From the analysis of the calculated electronic band structure as well as the density of states for both compounds, a strong hybridization between d states of the higher valent transition metal (TM) atoms (Co, Ru) and lower valent TM atoms of (Mn) is observed. Furthermore, total and partial density of states (PDOS) of the ground state and the results of spin magnetic moments reveal that these compounds are both stable and ideal half-metallic ferromagnetic. The effects of the unit cell volume on the magnetic properties and half-metaliicity are crucial. It is worth noting that our computed results of the total spin magnetic moments, for CoMnTe equal to 4 ~tB and 3 p-B per unit cell for RuMnTe, nicely follow the rule μ2tot = Zt - 18. Using the quasi-harmonic Debye model, which considers the phononic effects, the effecs of pressure P and temperature T on the lattice parameter, bulk modulus, thermal expansion coefficient, Debye temperature, and heat capacity for these compounds are investigated for the first time.