The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides...The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.展开更多
Objective Alzheimer’s disease(AD)has become a significant global concern,but effective drugs able to slow down AD progression is still lacked.Electroacupuncture(EA)has been demonstrated to ameliorate cognitive impair...Objective Alzheimer’s disease(AD)has become a significant global concern,but effective drugs able to slow down AD progression is still lacked.Electroacupuncture(EA)has been demonstrated to ameliorate cognitive impairment in individuals with AD.However,the underlying mechanisms remains poorly understood.This study aimed at examining the neuroprotective properties of EA and its potential mechanism of action against AD.Methods APP/PS1 transgenic mice were employed to evaluate the protective effects of EA on Shenshu(BL 23)and Baihui(GV 20).Chemogenetic manipulation was used to activate or inhibit serotonergic neurons within the dorsal raphe nucleus(DRN).Learning and memory abilities were assessed by the novel object recognition and Morris water maze tests.Golgi staining,western blot,and immunostaining were utilized to determine EA-induced neuroprotection.Results EA at Shenshu(BL 23)and Baihui(GV 20)effectively ameliorated learning and memory impairments in APP/PS1 mice.EA attenuated dendritic spine loss,increased the expression levels of PSD95,synaptophysin,and brain-derived neurotrophic factor in hippocampus.Activation of serotonergic neurons within the DRN can ameliorate cognitive deficits in AD by activating glutamatergic neurons mediated by 5-HT1B.Chemogenetic inhibition of serotonergic neurons in the DRN reversed the effects of EA on synaptic plasticity and memory.Conclusion EA can alleviate cognitive dysfunction in APP/PS1 mice by activating serotonergic neurons in the DRN.Further study is necessary to better understand how the serotonergic neurons-related neural circuits involves in EA-induced memory improvement in AD.展开更多
A good quality(5 at.%Yb:GdScO_(3))single crystal of F30 mm37 mm was grown successfully by the Czochralski method.Its structure is studied by the x-ray diffraction(XRD),and its atomic coordinates are obtained by Rietve...A good quality(5 at.%Yb:GdScO_(3))single crystal of F30 mm37 mm was grown successfully by the Czochralski method.Its structure is studied by the x-ray diffraction(XRD),and its atomic coordinates are obtained by Rietveld refinement.The crystal field energy level splitting of Yb^(3+)in GdScO_(3) is determined by employing the absorption and photoluminescence spectra at 8 K.Only ^(2)F_(7/2)(4)is far from the ground state ^(2)F_(7/2)(1)by 710 cm-1 among the crystal field energy levels split from ^(2)F_(7/2),so it is more easier to realize the laser operation of ^(2)F5/2(1)^(2)F_(7/2)(4)with wavelength 1060 nm.The spin–orbit coupling parameters and intrinsic crystal field parameters(CFPs).The intrinsic crystal field parameters¯B k(k=2,4,6)of the crystal were fitted by the superposition model.The CFPs evaluated with¯Bk and coordination factor are taken as the initial parameters to fit the crystal field energy levels of the crystal,and the crystal field parameters Bk q are obtained finally with the root-mean-square deviation 9 cm-1.It is suggested that the ligand point charge,covalency and overlap interaction are slightly weaker than charge interpenetration and coulomb exchange interaction for Yb^(3+)in GdScO_(3).The obtained Hamiltonian parameters can be used to calculate crystal field energy levels and wave functions of Yb:GdScO_(3) to analyze the mechanism of the luminescence or laser.展开更多
BACKGROUND The precise role of mitochondrial carrier homolog 2(MTCH2)in promoting malignancy in gastric mucosal cells and its involvement in gastric cancer cell metastasis have not been fully elucidated.AIM To determi...BACKGROUND The precise role of mitochondrial carrier homolog 2(MTCH2)in promoting malignancy in gastric mucosal cells and its involvement in gastric cancer cell metastasis have not been fully elucidated.AIM To determine the role of MTCH2 in gastric cancer.METHODS We collected 65 samples of poorly differentiated gastric cancer tissue and adjacent tissues,constructed MTCH2-overexpressing and MTCH2-knockdown cell models,and evaluated the proliferation,migration,and invasion of human gastric epithelial cells(GES-1)and human gastric cancer cells(AGS)cells.The mito-chondrial membrane potential(MMP),mitochondrial permeability transformation pore(mPTP)and ATP fluorescence probe were used to detect mitochondrial function.Mitochondrial function and ATP synthase protein levels were detected via Western blotting.RESULTS The expression of MTCH2 and ATP2A2 in gastric cancer tissues was significantly greater than that in adjacent tissues.Overexpression of MTCH2 promoted colony formation,invasion,migration,MMP expression and ATP production in GES-1 and AGS cells while upregulating ATP2A2 expression and inhibiting cell apoptosis;knockdown of MTCH2 had the opposite effect,promoting overactivation of the mPTP and promoting apoptosis.CONCLUSION MTCH2 can increase the malignant phenotype of GES-1 cells and promote the proliferation,invasion,and migration of gastric cancer cells by regulating mitochondrial function,providing a basis for targeted therapy for gastric cancer cells.展开更多
BACKGROUND Gastric ulcers(GUs)have a high risk of clinical morbidity and recurrence,and further exploration is needed for the prevention,diagnosis,and treatment of the disease.AIM To investigated the effects of a diet...BACKGROUND Gastric ulcers(GUs)have a high risk of clinical morbidity and recurrence,and further exploration is needed for the prevention,diagnosis,and treatment of the disease.AIM To investigated the effects of a diet plan on pepsinogen(PG)I,PG II,gastrin-17(G-17)levels and nutritional status in patients with GUs.METHODS A total of 100 patients with GUs treated between May 2022 and May 2023 were enrolled,with 47 patients in the control group receiving routine nursing and 53 patients in the experimental group receiving dietary nursing intervention based on a diet plan.The study compared the two groups in terms of nursing efficacy,adverse events(vomiting,acid reflux,and celialgia),time to symptom improvement(burning sensation,acid reflux,and celialgia),gastric function(PG I,PG II,and G-17 levels),and nutritional status[prealbumin(PA)and albumin(ALB)levels].RESULTS The experimental group showed a markedly higher total effective rate of nursing,a significantly lower incidence of adverse events,and a shorter time to symptom improvement than the control group.Additionally,the experimental group’s post-intervention PG I,PG II,and G-17 levels were significantly lower than preintervention or control group levels,whereas PA and ALB levels were significantly higher.CONCLUSION The diet plan significantly reduced PG I,PG II,and G-17 levels in patients with GUs and significantly improved their nutritional status.展开更多
The basic leucine zipper(bZIP)transcription factor HY5 plays a multifaceted role in plant growth and development.Here the apple MdHY5 gene was cloned based on its homology with Arabidopsis HY5.Expression analysis demo...The basic leucine zipper(bZIP)transcription factor HY5 plays a multifaceted role in plant growth and development.Here the apple MdHY5 gene was cloned based on its homology with Arabidopsis HY5.Expression analysis demonstrated that MdHY5 transcription was induced by light and abscisic acid treatments.Electrophoretic mobility shift assays and transient expression assays subsequently showed that MdHY5 positively regulated both its own transcription and that of MdMYB10 by binding to E-box and G-box motifs,respectively.Furthermore,we obtained transgenic apple calli that overexpressed the MdHY5 gene,and apple calli coloration assays showed that MdHY5 promoted anthocyanin accumulation by regulating expression of the MdMYB10 gene and downstream anthocyanin biosynthesis genes.In addition,the transcript levels of a series of nitrate reductase genes and nitrate uptake genes in both wild-type and transgenic apple calli were detected.In association with increased nitrate reductase activities and nitrate contents,the results indicated that MdHY5 might be an important regulator in nutrient assimilation.Taken together,these results indicate that MdHY5 plays a vital role in anthocyanin accumulation and nitrate assimilation in apple.展开更多
AIM To detect the expression of Raf kinase inhibitory protein(RKIP) in gastrointestinal stromal tumors(GISTs) and to analyze its relationship with clinicopatholgical characteristics and prognosis of this disease.METHO...AIM To detect the expression of Raf kinase inhibitory protein(RKIP) in gastrointestinal stromal tumors(GISTs) and to analyze its relationship with clinicopatholgical characteristics and prognosis of this disease.METHODS Sixty-three patients with pathologically diagnosed GISTs who underwent surgical resection at the Shengjing Hospital of China Medical University from January 2011 to January 2015 and had complete clinical,pathological,and follow-up data were included. Immunohistochemical method was used to detect the expression of RKIP in GIST tissue samples from these patients. KaplanMeier method was used to calculate the survival rate of 60 patients with complete follow-up data,and Cox regression analysis was performed to identify factors affecting the prognosis of patients GISTs to evaluate further the diagnostic and prognostic value of RKIP in GISTs.RESULTS In GIST tissues,RKIP positive signals,manifesting as brownish yellow or brown granules,were located in the cytoplasm or on the membrane. Of 63 tissue samplesincluded in this study,34(54%) were positive and 29(46%) were negative for RKIP expression. Statistical analysis showed that RKIP expression in GISTs was significantly associated with tumor size,National Institutes of Health(NIH) risk grade,and mucosal invasion,but had no significant association with age,gender,tumor location,or the number of mitotic figures. Univariate Kaplan-Meier analysis revealed that the 1-,3-,and 5-year survival rates were 94.4%,89.2%,and 80.5% for patients with positive RKIP expression,and 88.6%,68.2%,and 48.2% for patients with negative RKIP expression,suggesting that patients with high RKIP expression had significantly higher survival rates than those with low expression(Log-rank test,P = 0.0015). Cox regression analysis demonstrated that NIH risk grade was significantly associated with the prognosis of GISTs(P = 0.037),suggesting that NIH risk grade is a significant predictor of the prognosis of GISTs. RKIP expression had a tendency to predict the survival of GISTs(P = 0.122),suggesting that RKIP expression may have appreciated value to predict the prognosis of GISTs.CONCLUSION This study demonstrated that:(1) RKIP expression in GISTs is associated with tumor size,NIH risk grade,and mucosal invasion,and low or no expression of RKIP predicts a high malignancy potential;(2) high RKIP correlates positively with the survival of patients with GISTs; and(3) RKIP expression has appreciated value for predicting the survival of patients with GISTs,although it is not an independent prognostic factor in GISTs.展开更多
The nuclides inhaled during nuclear accidents usually cause internal contamination of the lungs with low activity.Although a parallel-hole imaging system,which is widely used in medical gamma cameras,has a high resolu...The nuclides inhaled during nuclear accidents usually cause internal contamination of the lungs with low activity.Although a parallel-hole imaging system,which is widely used in medical gamma cameras,has a high resolution and good image quality,owing to its extremely low detection efficiency,it remains difficult to obtain images of inhaled lung contamination.In this study,the Monte Carlo method was used to study the internal lung contamination imaging using the MPA-MURA coded-aperture collimator.The imaging system consisted of an adult male lung model,with a mosaicked,pattern-centered,and anti-symmetric MURA coded-aperture collimator model and a CsI(Tl)detector model.The MLEM decoding algorithm was used to reconstruct the internal contamination image,and the complementary imaging method was used to reduce the number of artifacts.The full width at half maximum of the I-131 point source image reconstructed by the MPAMURA coded-aperture imaging reached 2.51 mm,and the signal-to-noise ratio of the simplified respiratory tract source(I-131)image reconstructed through MPA-MURA coded-aperture imaging was 3.98 dB.Although the spatial resolution of MPA-MURA coded-aperture imaging is not as good as that of parallel-hole imaging,the detection efficiency of PMA-MURA coded-aperture imaging is two orders of magnitude higher than that of parallel-hole collimator imaging.Considering the low activity level of internal lung contamination caused by nuclear accidents,PMA-MURA coded-aperture imaging has significant potential for the development of lung contamination imaging.展开更多
As an important primary metabolite,malate plays a key role in regulating osmotic pressure,pH homeostasis,stress tolerance,and fruit quality of apple.The R2R3-MYB transcription factor(TF)MdMYB73 was identified as a pro...As an important primary metabolite,malate plays a key role in regulating osmotic pressure,pH homeostasis,stress tolerance,and fruit quality of apple.The R2R3-MYB transcription factor(TF)MdMYB73 was identified as a protein that plays a critical role in determining malate accumulation and vacuolar acidification by directly regulating the transcription of aluminum-activated malate transporter 9(MdALMT9),vacuolar ATPase subunit A(MdVHA-A),and vacuolar pyrophosphatase 1(MdVHP1)in apple.In addition,the bHLH TF MdCIbHLH1 interacts with MdMYB73 and enhances the transcriptional activity of MdMYB73.Our previous studies demonstrated that the BTB-BACK-TAZ domain protein MdBT2 can degrade MdCIbHLH1 to influence malate accumulation and vacuolar acidification.However,the potential upstream regulators of MdMYB73 are currently unknown.In this study,we found that MdBT2 directly interacts with and degrades MdMYB73 through the ubiquitin/26S proteasome pathway to regulate malate accumulation and vacuolar acidification.A series of functional assays with apple calli and fruit showed that MdBT2 controls malate accumulation and vacuolar acidification in an MdMYB73-dependent manner.Overall,our findings shed light on the mechanism by which the BTB-BACK-TAZ domain protein MdBT2 regulates malate accumulation and vacuolar acidification by targeting MdMYB73 and MdCIbHLH1 for ubiquitination in apple.This information may help guide traditional breeding programs and fruit tree molecular breeding,and lead to improvements in fruit quality and stress tolerance.展开更多
Previous studies on the prognostic significance of serum levels of androgens in patients with chronic heart failure (CHF) have yielded conflicting results. The aim of this study was to examine the relationship betwe...Previous studies on the prognostic significance of serum levels of androgens in patients with chronic heart failure (CHF) have yielded conflicting results. The aim of this study was to examine the relationship between serum concentration of testosterone and mortality in men with systolic CHF. A total of 175 elderly men (age ≥60 years) with CHF were recruited. Total testosterone (TI') and sex hormone-binding globulin (SHBG) were measured, and estimated free testosterone (eFT) was calculated. The median follow-up time was 3.46 years. Of these patients, 17 had a TT level below 8 nmol I^-1 (230 ng dI^-1), 27 had an eFT level below 0.225 nmol I^-1 (65 pg ml^-1) and 12 had both. Using the age-specific tenth percentiles of TT and eFT in healthy men in our laboratory as cutoff points, the prevalences of TT and eFT deficiency was 21.7% (38/175) and 27.4% (48/175), respectively. Both TT and eFT were inversely associated with left ventricular ejection fraction (LVEF) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) (all P〈0.01). Kaplan-Meier curves for patients in low, medium and high tertiles according to TT and eFT level showed significantly different cumulative survival rate (both P〈0.01 by log-rank test). However, after adjustment for clinical variables, there were no significant associations of either TT or eFT levels with survival time (0R=0.97, 95% CI: 0.84-1.12, P=0.28 and 0R=0.92, 95% CI: 0.82-1.06, P=0.14, respectively). Our study showed that levels of TT and eFT are commonly decreased in elderly patients with systolic CHF and related to disease severity, but they are not independent predictors for mortality.展开更多
BACKGROUND Anterior bone loss(ABL)is a relatively easily neglected condition after cervical disc replacement(CDR).Whether this phenomenon is a radiological anomaly or a complication remains controversial.Several studi...BACKGROUND Anterior bone loss(ABL)is a relatively easily neglected condition after cervical disc replacement(CDR).Whether this phenomenon is a radiological anomaly or a complication remains controversial.Several studies have reported the clinical characteristics of ABL and speculated on the pathogenic mechanism based on a certain type of artificial disc,while the overall understanding of ABL is lacking.AIM To describe the prevalence,impacts,and risk factors of ABL after CDR.METHODS We searched the PubMed,Cochrane Library,and Excerpta Medica databases using the terms“bone loss”or“bone remodeling”or“bone absorption”or“osteolysis”or“implant loosening”or“implant migration”or“hypersensitivity”or“hyperreactivity”,“cervical disc replacement”or“cervical disc arthroplasty”or“total disc replacement”.Eligible manuscripts on the prevalence and impacts of ABL were reviewed by the authors.Data extraction was performed using an established extraction form.The results of the included studies were described narratively.RESULTS Six studies met the inclusion and exclusion criteria.One was a prospective study and the others were retrospective studies.A total of 440 patients with 536 segments were included.The artificial cervical discs included Bryan,Baguera-C,Discocerv,and Mobi-C.The prevalence of ABL ranged from 3.13%to 91.89%,with a combined overall prevalence of 41.84%.ABL occurred within 6 mo and stopped 12 mo after surgery.Several cases were noted to have a self-healing process.Severe ABL resulted in segmental kyphosis,implant subsidence,and persistent neck pain.ABL may be related to heterotopic ossification.Multilevel surgery may be one of the risk factors for ABL.CONCLUSION ABL is a common condition after CDR.The underlying mechanisms of ABL may include stress concentration and injury to nutrient vessels.ABL should be considered a complication after CDR as it was associated with neck pain,implant subsidence,and heterotopic ossification.展开更多
Objective Several previous studies have shown androgens deficiency in men with CHF, and 2 studies on the prognostic significance of serum levels of androgens in CHF patients have yielded conflicting results. The aim o...Objective Several previous studies have shown androgens deficiency in men with CHF, and 2 studies on the prognostic significance of serum levels of androgens in CHF patients have yielded conflicting results. The aim of this study was to examine the relationship between serum concentration of testosterone and mortality in men with systolic CHE Methods A total of 175 elderly (age ≥ 60 years) men with CHF were recruited. Total testosterone fiT) and sex hormone binding globulin (SHBG) were measured, and free serum testosterone (eFT) was calculated. The median follow-up time was 1262 days. Results During follow-up 54 (30.9%) patients died. TT and eFF deficiency was found in 21.7% (38/175) and 27.4% (48/175) patients, respectively. Both TT and eFT were inversely associated with LVEF and NT-proBNP (all P〈0.01). Kaplan-Meier curves for patients in low, medium and high tertiles according to TF and eFT level showed significantly different cumulative survival rate (both P〈0.01 by log-rank test). However, after adjustment for clinical variables, there were no significant associations between either Tr or eFT levels or survival time (OR=0.97, 95% CI, 0.84-1.12, P--0.28; and OR=0.92, 95% CI, 0.82-1.06,/'=0.14, respectively). Conclusion Our study showed that although levels of TT and eFT are commonly decreased in elderly patients with systolic CHF and related to disease severity, they are not independent predictors for mortality展开更多
Nitrogen is an important factor that affects plant anthocyanin accumulation.In apple,the nitrate-responsive BTB/TAZ protein MdBT2 negatively regulates anthocyanin biosynthesis.In this study,we found that MdBT2 undergo...Nitrogen is an important factor that affects plant anthocyanin accumulation.In apple,the nitrate-responsive BTB/TAZ protein MdBT2 negatively regulates anthocyanin biosynthesis.In this study,we found that MdBT2 undergoes posttranslational modifications in response to nitrate deficiency.Yeast two-hybrid,protein pull-down,and bimolecular fluorescence complementation(BiFC)assays showed that MdBT2 interacts with MdGRF11,a 14-3-3 protein;14-3-3 proteins compose a family of highly conserved phosphopeptide-binding proteins involved in multiple physiological and biological processes.The interaction of MdGRF11 negatively regulated the stability of the MdBT2 protein via a 26S proteasome-dependent pathway,which increased the abundance of MdMYB1 proteins to activate the expression of anthocyanin biosynthesis-related genes.Taken together,the results demonstrate the critical role of 14-3-3 proteins in the regulation of nitrate deficiency-induced anthocyanin accumulation.Our results provide a novel avenue to elucidate the mechanism underlying the induction of anthocyanin biosynthesis in response to nitrate deficiency.展开更多
A novel Ga N-based vertical heterostructure field effect transistor(HFET) with nonuniform doping superjunctions(non-SJ HFET) is proposed and studied by Silvaco-ATLAS,for minimizing the specific on-resistance(RonA...A novel Ga N-based vertical heterostructure field effect transistor(HFET) with nonuniform doping superjunctions(non-SJ HFET) is proposed and studied by Silvaco-ATLAS,for minimizing the specific on-resistance(RonA) at no expense of breakdown voltage(BV).The feature of non-SJ HFET lies in the nonuniform doping concentration from top to bottom in the n-and p-pillars,which is different from that of the conventional Ga N-based vertical HFET with uniform doping superjunctions(un-SJ HFET).A physically intrinsic mechanism for the nonuniform doping superjunction(non-SJ) to further reduce RonA at no expense of BV is investigated and revealed in detail.The design,related to the structure parameters of non-SJ,is optimized to minimize the RonA on the basis of the same BV as that of un-SJ HFET.Optimized simulation results show that the reduction in RonA depends on the doping concentrations and thickness values of the light and heavy doping parts in non-SJ.The maximum reduction of more than 51% in RonA could be achieved with a BV of 1890 V.These results could demonstrate the superiority of non-SJ HFET in minimizing RonA and provide a useful reference for further developing the Ga N-based vertical HFETs.展开更多
The Yb:YAG is an excellent high-average power and ultra-short pulse laser crystal. Transition intensity parameters A(tp)~k and Huang–Rhys factors are fitted to its emission spectrum by the full-profile fitting met...The Yb:YAG is an excellent high-average power and ultra-short pulse laser crystal. Transition intensity parameters A(tp)~k and Huang–Rhys factors are fitted to its emission spectrum by the full-profile fitting method. Calculated results indicate that the emission spectrum of Yb:YAG at cryogenic temperature consists of three pure electron state transitions and two phononassisted transitions, one vibronic transition releases one-phonon of 3 cm^(-1), and the other vibronic transition absorbs onephonon of 22 cm^(-1). At 300 K, the phonon assisted transition of 3 cm^(-1) turns into two-or more-phonon assisted transitions.The procedure absorbing phonon can reduce the thermal load of Yb:YAG and improve the laser efficiency, which may be one of the reasons why Yb:YAG has excellent performance. The emission bands of Yb:YAG are broadened thermally, and the peak values decrease by several times. The emission cross sections of Yb:YAG determined by Fuchtbauer–Ladenburg(F–L) formula are remarkably different from those calculated with A(tp)~k, which indicates that it is necessary for a laser material to determine its transition intensity parameters A(tp)~kin order to reasonably evaluate the laser performance.展开更多
BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important fo...BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important for resolving patients’symptoms and maintaining the normal functioning of cervical implants.However,the use of inappropriate surgical strategies could lead to complications such as implant migration and neurological deficit.In this paper,we summarize our surgical strategies used in multilevel cervical disc replacement and hybrid surgery into five major notes.CASE SUMMARY We share the key notes and our surgical procedures in the form of four typical case presentations.All patients were diagnosed with cervical degenerative disc disease with myelopathy or radiculopathy and needed multilevel cervical spine surgery.The first case demonstrated that index levels indicating the presence of highly serious spinal cord compression required a prioritized decompression.The second case demonstrated that the disc replacement should be performed before fusion in cervical hybrid surgery.The third and forth cases demonstrated that a top-down implantation sequence was needed in continuous two-level cervical disc replacement.The symptoms of all patients were significantly relieved after surgery.CONCLUSION We hope that our surgical strategies can help improve the performance and outcomes of multilevel cervical spine surgery.展开更多
Nitrate is a major nitrogen resource for plant growth and development and acts as both a crucial nutrient and a signaling molecule for plants;hence,understanding nitrate signaling is important for crop production.Absc...Nitrate is a major nitrogen resource for plant growth and development and acts as both a crucial nutrient and a signaling molecule for plants;hence,understanding nitrate signaling is important for crop production.Abscisic acid(ABA)has been demonstrated to be involved in nitrate signaling,but the underlying mechanism is largely unknown in apple.In this study,we found that exogenous ABA inhibited the transport of nitrate from roots to shoots in apple,and the transcription of the nitrate transporter MdNRT1.5/MdNPF7.3 was noticeably reduced at the transcriptional level by ABA,which inhibited the transport of nitrate from roots to shoots.Then,it was found that the ABA-responsive transcription factor MdABI5 bound directly to the ABRE recognition site of the MdNRT1.5 promoter and suppressed its expression.Overexpression of MdABI5 inhibited ABA-mediated transport of nitrate from roots to shoots.Overall,these results demonstrate that MdABI5 regulates the transport of nitrate from roots to shoots partially by mediating the expression of MdNRT1.5,illuminating the molecular mechanism by which ABA regulates nitrate transport in apple.展开更多
There is a comm on sense view for atomic magnetometers that their spin-projection-noises(SPNs) are inversely proportional to (T_2)^(1/2), where (T_2)^(1/2) is the transverse relaxation time. We analyze the current ato...There is a comm on sense view for atomic magnetometers that their spin-projection-noises(SPNs) are inversely proportional to (T_2)^(1/2), where (T_2)^(1/2) is the transverse relaxation time. We analyze the current atomic magnetometer types and give a counter-example of this common sense, which is the all-optical spin precession modulated threeaxis atomic magnetometer proposed by our group in 2015. Unlike the other atomic magnetometers, the SPN of this kind of atomic magnetometers is proportional to (T_2)^(1/2) due to the fact that the scale factor between P_x and B can be unrelated to the transverse relaxation time T_2. We demonstrate this irrelevance experimentally and analyze the SPN theoretically. Using short-pulse ultra-high power laser to fully polarize the atoms, the phenomenon that SPN decreases with T_2 may also be demonstrated experimentally and a new tool for researching SPN in atomic magnetometers may be realized.展开更多
Owing to the unique structural,electronic,and physico-chemical properties,molybdenum clusters are expected to play an important role in future nanotechnologies.However,their ground states are still under debate.In thi...Owing to the unique structural,electronic,and physico-chemical properties,molybdenum clusters are expected to play an important role in future nanotechnologies.However,their ground states are still under debate.In this study,the crystal structure analysis by particle swarm optimization(CALYPSO)approach is used for the global minimum search,which is followed by first-principles calculations,to detect an obvious dimerization tendency in Mo_(n)(n=2-18)clusters when the 4s and 4p semicore states are not regarded as the valence states.Further,the clusters with even number of atoms are usually magic clusters with high stability.However,after including the4 s and 4 p electrons as valence electrons,the dimerization tendency exhibits a drastic reduction because the average hybridization indices H_(sp),H_(sd),and H_(pd) are reduced significantly.Overall,this work reports new ground states of Mo_(n)(n=11,14,15)clusters and proves that semicore states are essential for Mo_(n) clusters.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12125509,12222514,11961141003,and 12005304)National Key Research and Development Project(No.2022YFA1602301)+1 种基金CAST Young Talent Support Planthe CNNC Science Fund for Talented Young Scholars Continuous support for basic scientific research projects。
文摘The Moon provides a unique environment for investigating nearby astrophysical events such as supernovae.Lunar samples retain valuable information from these events,via detectable long-lived“fingerprint”radionuclides such as^(60)Fe.In this work,we stepped up the development of an accelerator mass spectrometry(AMS)method for detecting^(60)Fe using the HI-13tandem accelerator at the China Institute of Atomic Energy(CIAE).Since interferences could not be sufficiently removed solely with the existing magnetic systems of the tandem accelerator and the following Q3D magnetic spectrograph,a Wien filter with a maximum voltage of±60 kV and a maximum magnetic field of 0.3 T was installed after the accelerator magnetic systems to lower the detection background for the low abundance nuclide^(60)Fe.A 1μm thick Si_(3)N_(4) foil was installed in front of the Q3D as an energy degrader.For particle detection,a multi-anode gas ionization chamber was mounted at the center of the focal plane of the spectrograph.Finally,an^(60)Fe sample with an abundance of 1.125×10^(-10)was used to test the new AMS system.These results indicate that^(60)Fe can be clearly distinguished from the isobar^(60)Ni.The sensitivity was assessed to be better than 4.3×10^(-14)based on blank sample measurements lasting 5.8 h,and the sensitivity could,in principle,be expected to be approximately 2.5×10^(-15)when the data were accumulated for 100 h,which is feasible for future lunar sample measurements because the main contaminants were sufficiently separated.
基金supported by grants from the Shenzhen Science and Technology Program(No.2021-22154)National Natural Science Foundation of China(No.82205271,No.82374564,and No.82074566)+1 种基金Wuhan Medical Research Project(No.WZ21Q09)Key Chinese Medicine Project of Hubei Provincial Natural Science Foundation(No.2023AFD112).
文摘Objective Alzheimer’s disease(AD)has become a significant global concern,but effective drugs able to slow down AD progression is still lacked.Electroacupuncture(EA)has been demonstrated to ameliorate cognitive impairment in individuals with AD.However,the underlying mechanisms remains poorly understood.This study aimed at examining the neuroprotective properties of EA and its potential mechanism of action against AD.Methods APP/PS1 transgenic mice were employed to evaluate the protective effects of EA on Shenshu(BL 23)and Baihui(GV 20).Chemogenetic manipulation was used to activate or inhibit serotonergic neurons within the dorsal raphe nucleus(DRN).Learning and memory abilities were assessed by the novel object recognition and Morris water maze tests.Golgi staining,western blot,and immunostaining were utilized to determine EA-induced neuroprotection.Results EA at Shenshu(BL 23)and Baihui(GV 20)effectively ameliorated learning and memory impairments in APP/PS1 mice.EA attenuated dendritic spine loss,increased the expression levels of PSD95,synaptophysin,and brain-derived neurotrophic factor in hippocampus.Activation of serotonergic neurons within the DRN can ameliorate cognitive deficits in AD by activating glutamatergic neurons mediated by 5-HT1B.Chemogenetic inhibition of serotonergic neurons in the DRN reversed the effects of EA on synaptic plasticity and memory.Conclusion EA can alleviate cognitive dysfunction in APP/PS1 mice by activating serotonergic neurons in the DRN.Further study is necessary to better understand how the serotonergic neurons-related neural circuits involves in EA-induced memory improvement in AD.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFB3605700 and 2023YFB3507403)the National Natural Science Foundation of China(Grant No.52272011)+2 种基金the Youth Innovation Promotion Association of CAS(Grant No.2023463)Plan for Anhui Major Provincial Science&Technology Project(Grant No.202203a05020002)Open Project of Advanced Laser Technology Laboratory of Anhui Province(Grant No.AHL20220ZR04).
文摘A good quality(5 at.%Yb:GdScO_(3))single crystal of F30 mm37 mm was grown successfully by the Czochralski method.Its structure is studied by the x-ray diffraction(XRD),and its atomic coordinates are obtained by Rietveld refinement.The crystal field energy level splitting of Yb^(3+)in GdScO_(3) is determined by employing the absorption and photoluminescence spectra at 8 K.Only ^(2)F_(7/2)(4)is far from the ground state ^(2)F_(7/2)(1)by 710 cm-1 among the crystal field energy levels split from ^(2)F_(7/2),so it is more easier to realize the laser operation of ^(2)F5/2(1)^(2)F_(7/2)(4)with wavelength 1060 nm.The spin–orbit coupling parameters and intrinsic crystal field parameters(CFPs).The intrinsic crystal field parameters¯B k(k=2,4,6)of the crystal were fitted by the superposition model.The CFPs evaluated with¯Bk and coordination factor are taken as the initial parameters to fit the crystal field energy levels of the crystal,and the crystal field parameters Bk q are obtained finally with the root-mean-square deviation 9 cm-1.It is suggested that the ligand point charge,covalency and overlap interaction are slightly weaker than charge interpenetration and coulomb exchange interaction for Yb^(3+)in GdScO_(3).The obtained Hamiltonian parameters can be used to calculate crystal field energy levels and wave functions of Yb:GdScO_(3) to analyze the mechanism of the luminescence or laser.
基金the Medical Science Research Projects in Hebei Province,No.20221526and Natural Science Foundation,No.2022-271.
文摘BACKGROUND The precise role of mitochondrial carrier homolog 2(MTCH2)in promoting malignancy in gastric mucosal cells and its involvement in gastric cancer cell metastasis have not been fully elucidated.AIM To determine the role of MTCH2 in gastric cancer.METHODS We collected 65 samples of poorly differentiated gastric cancer tissue and adjacent tissues,constructed MTCH2-overexpressing and MTCH2-knockdown cell models,and evaluated the proliferation,migration,and invasion of human gastric epithelial cells(GES-1)and human gastric cancer cells(AGS)cells.The mito-chondrial membrane potential(MMP),mitochondrial permeability transformation pore(mPTP)and ATP fluorescence probe were used to detect mitochondrial function.Mitochondrial function and ATP synthase protein levels were detected via Western blotting.RESULTS The expression of MTCH2 and ATP2A2 in gastric cancer tissues was significantly greater than that in adjacent tissues.Overexpression of MTCH2 promoted colony formation,invasion,migration,MMP expression and ATP production in GES-1 and AGS cells while upregulating ATP2A2 expression and inhibiting cell apoptosis;knockdown of MTCH2 had the opposite effect,promoting overactivation of the mPTP and promoting apoptosis.CONCLUSION MTCH2 can increase the malignant phenotype of GES-1 cells and promote the proliferation,invasion,and migration of gastric cancer cells by regulating mitochondrial function,providing a basis for targeted therapy for gastric cancer cells.
基金the Ethic Committee of Lujiang County Hospital of Traditional Chinese Medicine.
文摘BACKGROUND Gastric ulcers(GUs)have a high risk of clinical morbidity and recurrence,and further exploration is needed for the prevention,diagnosis,and treatment of the disease.AIM To investigated the effects of a diet plan on pepsinogen(PG)I,PG II,gastrin-17(G-17)levels and nutritional status in patients with GUs.METHODS A total of 100 patients with GUs treated between May 2022 and May 2023 were enrolled,with 47 patients in the control group receiving routine nursing and 53 patients in the experimental group receiving dietary nursing intervention based on a diet plan.The study compared the two groups in terms of nursing efficacy,adverse events(vomiting,acid reflux,and celialgia),time to symptom improvement(burning sensation,acid reflux,and celialgia),gastric function(PG I,PG II,and G-17 levels),and nutritional status[prealbumin(PA)and albumin(ALB)levels].RESULTS The experimental group showed a markedly higher total effective rate of nursing,a significantly lower incidence of adverse events,and a shorter time to symptom improvement than the control group.Additionally,the experimental group’s post-intervention PG I,PG II,and G-17 levels were significantly lower than preintervention or control group levels,whereas PA and ALB levels were significantly higher.CONCLUSION The diet plan significantly reduced PG I,PG II,and G-17 levels in patients with GUs and significantly improved their nutritional status.
基金This work was supported by grants from the Natural Science Foundation of China(31325024 and 31601742)the Ministry of Education of China(IRT15R42)and Shandong Province Government(SDAIT-06-03).
文摘The basic leucine zipper(bZIP)transcription factor HY5 plays a multifaceted role in plant growth and development.Here the apple MdHY5 gene was cloned based on its homology with Arabidopsis HY5.Expression analysis demonstrated that MdHY5 transcription was induced by light and abscisic acid treatments.Electrophoretic mobility shift assays and transient expression assays subsequently showed that MdHY5 positively regulated both its own transcription and that of MdMYB10 by binding to E-box and G-box motifs,respectively.Furthermore,we obtained transgenic apple calli that overexpressed the MdHY5 gene,and apple calli coloration assays showed that MdHY5 promoted anthocyanin accumulation by regulating expression of the MdMYB10 gene and downstream anthocyanin biosynthesis genes.In addition,the transcript levels of a series of nitrate reductase genes and nitrate uptake genes in both wild-type and transgenic apple calli were detected.In association with increased nitrate reductase activities and nitrate contents,the results indicated that MdHY5 might be an important regulator in nutrient assimilation.Taken together,these results indicate that MdHY5 plays a vital role in anthocyanin accumulation and nitrate assimilation in apple.
文摘AIM To detect the expression of Raf kinase inhibitory protein(RKIP) in gastrointestinal stromal tumors(GISTs) and to analyze its relationship with clinicopatholgical characteristics and prognosis of this disease.METHODS Sixty-three patients with pathologically diagnosed GISTs who underwent surgical resection at the Shengjing Hospital of China Medical University from January 2011 to January 2015 and had complete clinical,pathological,and follow-up data were included. Immunohistochemical method was used to detect the expression of RKIP in GIST tissue samples from these patients. KaplanMeier method was used to calculate the survival rate of 60 patients with complete follow-up data,and Cox regression analysis was performed to identify factors affecting the prognosis of patients GISTs to evaluate further the diagnostic and prognostic value of RKIP in GISTs.RESULTS In GIST tissues,RKIP positive signals,manifesting as brownish yellow or brown granules,were located in the cytoplasm or on the membrane. Of 63 tissue samplesincluded in this study,34(54%) were positive and 29(46%) were negative for RKIP expression. Statistical analysis showed that RKIP expression in GISTs was significantly associated with tumor size,National Institutes of Health(NIH) risk grade,and mucosal invasion,but had no significant association with age,gender,tumor location,or the number of mitotic figures. Univariate Kaplan-Meier analysis revealed that the 1-,3-,and 5-year survival rates were 94.4%,89.2%,and 80.5% for patients with positive RKIP expression,and 88.6%,68.2%,and 48.2% for patients with negative RKIP expression,suggesting that patients with high RKIP expression had significantly higher survival rates than those with low expression(Log-rank test,P = 0.0015). Cox regression analysis demonstrated that NIH risk grade was significantly associated with the prognosis of GISTs(P = 0.037),suggesting that NIH risk grade is a significant predictor of the prognosis of GISTs. RKIP expression had a tendency to predict the survival of GISTs(P = 0.122),suggesting that RKIP expression may have appreciated value to predict the prognosis of GISTs.CONCLUSION This study demonstrated that:(1) RKIP expression in GISTs is associated with tumor size,NIH risk grade,and mucosal invasion,and low or no expression of RKIP predicts a high malignancy potential;(2) high RKIP correlates positively with the survival of patients with GISTs; and(3) RKIP expression has appreciated value for predicting the survival of patients with GISTs,although it is not an independent prognostic factor in GISTs.
基金the Ministry of Science and Technology,People’s Republic of China(No.2012YQ180118)the National Natural Science Foundation of China(No.41874121)the Sichuan Science and Technology Program(No.2018JY0181).
文摘The nuclides inhaled during nuclear accidents usually cause internal contamination of the lungs with low activity.Although a parallel-hole imaging system,which is widely used in medical gamma cameras,has a high resolution and good image quality,owing to its extremely low detection efficiency,it remains difficult to obtain images of inhaled lung contamination.In this study,the Monte Carlo method was used to study the internal lung contamination imaging using the MPA-MURA coded-aperture collimator.The imaging system consisted of an adult male lung model,with a mosaicked,pattern-centered,and anti-symmetric MURA coded-aperture collimator model and a CsI(Tl)detector model.The MLEM decoding algorithm was used to reconstruct the internal contamination image,and the complementary imaging method was used to reduce the number of artifacts.The full width at half maximum of the I-131 point source image reconstructed by the MPAMURA coded-aperture imaging reached 2.51 mm,and the signal-to-noise ratio of the simplified respiratory tract source(I-131)image reconstructed through MPA-MURA coded-aperture imaging was 3.98 dB.Although the spatial resolution of MPA-MURA coded-aperture imaging is not as good as that of parallel-hole imaging,the detection efficiency of PMA-MURA coded-aperture imaging is two orders of magnitude higher than that of parallel-hole collimator imaging.Considering the low activity level of internal lung contamination caused by nuclear accidents,PMA-MURA coded-aperture imaging has significant potential for the development of lung contamination imaging.
基金supported by grants from the National Key Research and Development Program of China(2018YFD1000200)the National Natural Science Foundation of China(31972375)+1 种基金Ministry of Agriculture(CARS-27)Shandong Province(SDAIT-06-03).
文摘As an important primary metabolite,malate plays a key role in regulating osmotic pressure,pH homeostasis,stress tolerance,and fruit quality of apple.The R2R3-MYB transcription factor(TF)MdMYB73 was identified as a protein that plays a critical role in determining malate accumulation and vacuolar acidification by directly regulating the transcription of aluminum-activated malate transporter 9(MdALMT9),vacuolar ATPase subunit A(MdVHA-A),and vacuolar pyrophosphatase 1(MdVHP1)in apple.In addition,the bHLH TF MdCIbHLH1 interacts with MdMYB73 and enhances the transcriptional activity of MdMYB73.Our previous studies demonstrated that the BTB-BACK-TAZ domain protein MdBT2 can degrade MdCIbHLH1 to influence malate accumulation and vacuolar acidification.However,the potential upstream regulators of MdMYB73 are currently unknown.In this study,we found that MdBT2 directly interacts with and degrades MdMYB73 through the ubiquitin/26S proteasome pathway to regulate malate accumulation and vacuolar acidification.A series of functional assays with apple calli and fruit showed that MdBT2 controls malate accumulation and vacuolar acidification in an MdMYB73-dependent manner.Overall,our findings shed light on the mechanism by which the BTB-BACK-TAZ domain protein MdBT2 regulates malate accumulation and vacuolar acidification by targeting MdMYB73 and MdCIbHLH1 for ubiquitination in apple.This information may help guide traditional breeding programs and fruit tree molecular breeding,and lead to improvements in fruit quality and stress tolerance.
文摘Previous studies on the prognostic significance of serum levels of androgens in patients with chronic heart failure (CHF) have yielded conflicting results. The aim of this study was to examine the relationship between serum concentration of testosterone and mortality in men with systolic CHF. A total of 175 elderly men (age ≥60 years) with CHF were recruited. Total testosterone (TI') and sex hormone-binding globulin (SHBG) were measured, and estimated free testosterone (eFT) was calculated. The median follow-up time was 3.46 years. Of these patients, 17 had a TT level below 8 nmol I^-1 (230 ng dI^-1), 27 had an eFT level below 0.225 nmol I^-1 (65 pg ml^-1) and 12 had both. Using the age-specific tenth percentiles of TT and eFT in healthy men in our laboratory as cutoff points, the prevalences of TT and eFT deficiency was 21.7% (38/175) and 27.4% (48/175), respectively. Both TT and eFT were inversely associated with left ventricular ejection fraction (LVEF) and N-terminal pro-brain natriuretic peptide (NT-pro-BNP) (all P〈0.01). Kaplan-Meier curves for patients in low, medium and high tertiles according to TT and eFT level showed significantly different cumulative survival rate (both P〈0.01 by log-rank test). However, after adjustment for clinical variables, there were no significant associations of either TT or eFT levels with survival time (0R=0.97, 95% CI: 0.84-1.12, P=0.28 and 0R=0.92, 95% CI: 0.82-1.06, P=0.14, respectively). Our study showed that levels of TT and eFT are commonly decreased in elderly patients with systolic CHF and related to disease severity, but they are not independent predictors for mortality.
基金Supported by West China Nursing Discipline Development Special Fund Project,Sichuan University,No.HXHL190161.3.5 Project for Disciplines of Excellence,West China Hospital,Sichuan University,No.ZYJC18029.
文摘BACKGROUND Anterior bone loss(ABL)is a relatively easily neglected condition after cervical disc replacement(CDR).Whether this phenomenon is a radiological anomaly or a complication remains controversial.Several studies have reported the clinical characteristics of ABL and speculated on the pathogenic mechanism based on a certain type of artificial disc,while the overall understanding of ABL is lacking.AIM To describe the prevalence,impacts,and risk factors of ABL after CDR.METHODS We searched the PubMed,Cochrane Library,and Excerpta Medica databases using the terms“bone loss”or“bone remodeling”or“bone absorption”or“osteolysis”or“implant loosening”or“implant migration”or“hypersensitivity”or“hyperreactivity”,“cervical disc replacement”or“cervical disc arthroplasty”or“total disc replacement”.Eligible manuscripts on the prevalence and impacts of ABL were reviewed by the authors.Data extraction was performed using an established extraction form.The results of the included studies were described narratively.RESULTS Six studies met the inclusion and exclusion criteria.One was a prospective study and the others were retrospective studies.A total of 440 patients with 536 segments were included.The artificial cervical discs included Bryan,Baguera-C,Discocerv,and Mobi-C.The prevalence of ABL ranged from 3.13%to 91.89%,with a combined overall prevalence of 41.84%.ABL occurred within 6 mo and stopped 12 mo after surgery.Several cases were noted to have a self-healing process.Severe ABL resulted in segmental kyphosis,implant subsidence,and persistent neck pain.ABL may be related to heterotopic ossification.Multilevel surgery may be one of the risk factors for ABL.CONCLUSION ABL is a common condition after CDR.The underlying mechanisms of ABL may include stress concentration and injury to nutrient vessels.ABL should be considered a complication after CDR as it was associated with neck pain,implant subsidence,and heterotopic ossification.
基金Applied Basic Project of Sichuan Science and Technology Department(2018JY0202)Teaching Reform and Innovation Project of Shanxi Higher Education Institutions(J2016129)~~
文摘Objective Several previous studies have shown androgens deficiency in men with CHF, and 2 studies on the prognostic significance of serum levels of androgens in CHF patients have yielded conflicting results. The aim of this study was to examine the relationship between serum concentration of testosterone and mortality in men with systolic CHE Methods A total of 175 elderly (age ≥ 60 years) men with CHF were recruited. Total testosterone fiT) and sex hormone binding globulin (SHBG) were measured, and free serum testosterone (eFT) was calculated. The median follow-up time was 1262 days. Results During follow-up 54 (30.9%) patients died. TT and eFF deficiency was found in 21.7% (38/175) and 27.4% (48/175) patients, respectively. Both TT and eFT were inversely associated with LVEF and NT-proBNP (all P〈0.01). Kaplan-Meier curves for patients in low, medium and high tertiles according to TF and eFT level showed significantly different cumulative survival rate (both P〈0.01 by log-rank test). However, after adjustment for clinical variables, there were no significant associations between either Tr or eFT levels or survival time (OR=0.97, 95% CI, 0.84-1.12, P--0.28; and OR=0.92, 95% CI, 0.82-1.06,/'=0.14, respectively). Conclusion Our study showed that although levels of TT and eFT are commonly decreased in elderly patients with systolic CHF and related to disease severity, they are not independent predictors for mortality
基金the National Key R&D Program of China(2018YFD1000200)National Natural Science Foundation of China(31772288,31972378)Science and Technology Program of Yunnan Province(2019ZG002-1-03).
文摘Nitrogen is an important factor that affects plant anthocyanin accumulation.In apple,the nitrate-responsive BTB/TAZ protein MdBT2 negatively regulates anthocyanin biosynthesis.In this study,we found that MdBT2 undergoes posttranslational modifications in response to nitrate deficiency.Yeast two-hybrid,protein pull-down,and bimolecular fluorescence complementation(BiFC)assays showed that MdBT2 interacts with MdGRF11,a 14-3-3 protein;14-3-3 proteins compose a family of highly conserved phosphopeptide-binding proteins involved in multiple physiological and biological processes.The interaction of MdGRF11 negatively regulated the stability of the MdBT2 protein via a 26S proteasome-dependent pathway,which increased the abundance of MdMYB1 proteins to activate the expression of anthocyanin biosynthesis-related genes.Taken together,the results demonstrate the critical role of 14-3-3 proteins in the regulation of nitrate deficiency-induced anthocyanin accumulation.Our results provide a novel avenue to elucidate the mechanism underlying the induction of anthocyanin biosynthesis in response to nitrate deficiency.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61574112,61334002,61474091,and 61574110)the Natural Science Basic Research Plan in Shaanxi Province,China(Grant No.605119425012)
文摘A novel Ga N-based vertical heterostructure field effect transistor(HFET) with nonuniform doping superjunctions(non-SJ HFET) is proposed and studied by Silvaco-ATLAS,for minimizing the specific on-resistance(RonA) at no expense of breakdown voltage(BV).The feature of non-SJ HFET lies in the nonuniform doping concentration from top to bottom in the n-and p-pillars,which is different from that of the conventional Ga N-based vertical HFET with uniform doping superjunctions(un-SJ HFET).A physically intrinsic mechanism for the nonuniform doping superjunction(non-SJ) to further reduce RonA at no expense of BV is investigated and revealed in detail.The design,related to the structure parameters of non-SJ,is optimized to minimize the RonA on the basis of the same BV as that of un-SJ HFET.Optimized simulation results show that the reduction in RonA depends on the doping concentrations and thickness values of the light and heavy doping parts in non-SJ.The maximum reduction of more than 51% in RonA could be achieved with a BV of 1890 V.These results could demonstrate the superiority of non-SJ HFET in minimizing RonA and provide a useful reference for further developing the Ga N-based vertical HFETs.
基金supported by the National Natural Science Foundation of China(Grant Nos.61405206,51502292,and 51702322)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant Nos.CXJJ-16M251 and CXJJ-15M055)the National Key Research and Development Program of China(Grant No.2016YFB0402101)
文摘The Yb:YAG is an excellent high-average power and ultra-short pulse laser crystal. Transition intensity parameters A(tp)~k and Huang–Rhys factors are fitted to its emission spectrum by the full-profile fitting method. Calculated results indicate that the emission spectrum of Yb:YAG at cryogenic temperature consists of three pure electron state transitions and two phononassisted transitions, one vibronic transition releases one-phonon of 3 cm^(-1), and the other vibronic transition absorbs onephonon of 22 cm^(-1). At 300 K, the phonon assisted transition of 3 cm^(-1) turns into two-or more-phonon assisted transitions.The procedure absorbing phonon can reduce the thermal load of Yb:YAG and improve the laser efficiency, which may be one of the reasons why Yb:YAG has excellent performance. The emission bands of Yb:YAG are broadened thermally, and the peak values decrease by several times. The emission cross sections of Yb:YAG determined by Fuchtbauer–Ladenburg(F–L) formula are remarkably different from those calculated with A(tp)~k, which indicates that it is necessary for a laser material to determine its transition intensity parameters A(tp)~kin order to reasonably evaluate the laser performance.
文摘BACKGROUND Multilevel artificial cervical disc replacement and anterior hybrid surgery have been introduced as reliable treatments for multilevel cervical degenerative disc disease.Surgical techniques are important for resolving patients’symptoms and maintaining the normal functioning of cervical implants.However,the use of inappropriate surgical strategies could lead to complications such as implant migration and neurological deficit.In this paper,we summarize our surgical strategies used in multilevel cervical disc replacement and hybrid surgery into five major notes.CASE SUMMARY We share the key notes and our surgical procedures in the form of four typical case presentations.All patients were diagnosed with cervical degenerative disc disease with myelopathy or radiculopathy and needed multilevel cervical spine surgery.The first case demonstrated that index levels indicating the presence of highly serious spinal cord compression required a prioritized decompression.The second case demonstrated that the disc replacement should be performed before fusion in cervical hybrid surgery.The third and forth cases demonstrated that a top-down implantation sequence was needed in continuous two-level cervical disc replacement.The symptoms of all patients were significantly relieved after surgery.CONCLUSION We hope that our surgical strategies can help improve the performance and outcomes of multilevel cervical spine surgery.
基金This work was supported by grants from the National Key R&D Program of China(2018YFD1000100)National Natural Science Foundation of China(31772288 and 31972378)+1 种基金China Agriculture Research System of MOF and MARA(CARS-27)the Agricultural Variety Improvement Project of Shandong Province(2019LZGC007).
文摘Nitrate is a major nitrogen resource for plant growth and development and acts as both a crucial nutrient and a signaling molecule for plants;hence,understanding nitrate signaling is important for crop production.Abscisic acid(ABA)has been demonstrated to be involved in nitrate signaling,but the underlying mechanism is largely unknown in apple.In this study,we found that exogenous ABA inhibited the transport of nitrate from roots to shoots in apple,and the transcription of the nitrate transporter MdNRT1.5/MdNPF7.3 was noticeably reduced at the transcriptional level by ABA,which inhibited the transport of nitrate from roots to shoots.Then,it was found that the ABA-responsive transcription factor MdABI5 bound directly to the ABRE recognition site of the MdNRT1.5 promoter and suppressed its expression.Overexpression of MdABI5 inhibited ABA-mediated transport of nitrate from roots to shoots.Overall,these results demonstrate that MdABI5 regulates the transport of nitrate from roots to shoots partially by mediating the expression of MdNRT1.5,illuminating the molecular mechanism by which ABA regulates nitrate transport in apple.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51675034 and 61273067the Natural Science Foundation of Beijing Municipality under Grant No 7172123
文摘There is a comm on sense view for atomic magnetometers that their spin-projection-noises(SPNs) are inversely proportional to (T_2)^(1/2), where (T_2)^(1/2) is the transverse relaxation time. We analyze the current atomic magnetometer types and give a counter-example of this common sense, which is the all-optical spin precession modulated threeaxis atomic magnetometer proposed by our group in 2015. Unlike the other atomic magnetometers, the SPN of this kind of atomic magnetometers is proportional to (T_2)^(1/2) due to the fact that the scale factor between P_x and B can be unrelated to the transverse relaxation time T_2. We demonstrate this irrelevance experimentally and analyze the SPN theoretically. Using short-pulse ultra-high power laser to fully polarize the atoms, the phenomenon that SPN decreases with T_2 may also be demonstrated experimentally and a new tool for researching SPN in atomic magnetometers may be realized.
基金supported by the National Natural Science Foundation of China (No.11404098 and No.11604082)the Student Research Training Program of Henan University of Science and Technology(WLSRTP201911)
文摘Owing to the unique structural,electronic,and physico-chemical properties,molybdenum clusters are expected to play an important role in future nanotechnologies.However,their ground states are still under debate.In this study,the crystal structure analysis by particle swarm optimization(CALYPSO)approach is used for the global minimum search,which is followed by first-principles calculations,to detect an obvious dimerization tendency in Mo_(n)(n=2-18)clusters when the 4s and 4p semicore states are not regarded as the valence states.Further,the clusters with even number of atoms are usually magic clusters with high stability.However,after including the4 s and 4 p electrons as valence electrons,the dimerization tendency exhibits a drastic reduction because the average hybridization indices H_(sp),H_(sd),and H_(pd) are reduced significantly.Overall,this work reports new ground states of Mo_(n)(n=11,14,15)clusters and proves that semicore states are essential for Mo_(n) clusters.