Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,...Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,we performed single-cell ATAC-seq of human testis tissues and observed reprogramming during the transition from zygotene to pachytene spermatocytes.This event,conserved in mice,involved the deactivation of genes associated with meiosis after reprogramming and the activation of those related to spermatogenesis before their functional onset.Furthermore,we identified 282 transcriptional regulators(TRs)that underwent activation or deactivation subsequent to this process.Evidence suggested that physical contact signals from Sertoli cells may regulate these TRs in spermatocytes,while secreted ENHO signals may alter metabolic patterns in these cells.Our results further indicated that defective transcriptional reprogramming may be associated with non-obstructive azoospermia(NOA).This study revealed the importance of both physical contact and secreted signals between Sertoli cells and germ cells in meiotic progression.展开更多
Applying pressure has been evidenced as an effective method to control the properties of semiconductors,owing to its capability to modify the band configuration around Fermi energy.Correspondingly,structural evolution...Applying pressure has been evidenced as an effective method to control the properties of semiconductors,owing to its capability to modify the band configuration around Fermi energy.Correspondingly,structural evolutions under external pres-sures are required to analyze the mechanisms.Herein high-pressure structure of a magnetic doped semiconductor Ba(Zn_(0.95)Mn_(0.05))_(2)As_(2)is studied with combination of in-situ synchrotron X-ray diffractions and diamond anvil cells.The materials become ferromagnetic with Curie temperature of 105 K after further 20%K doping.The title material undergoes an isostruc-tural phase transition at around 19 GPa.Below the transition pressure,it is remarkable to find lengthening of Zn/Mn-As bond within Zn/MnAs layers,since chemical bonds are generally shortened with applying pressures.Accompanied with the bond stretch,interlayer As-As distances become shorter and the As-As dimers form after the phase transition.With further compres-sion,Zn/Mn-As bond becomes shortened due to the recovery of isotropic compression on the Zn/MnAs layers.展开更多
Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave(CDW) phase transition within a 1T-TaS_(2) l...Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave(CDW) phase transition within a 1T-TaS_(2) layer in a WS_(2)/1T-TaS_(2) heterostructure using time-resolved ultrafast spectroscopy. Laser-induced charge transfer doping strongly suppresses the commensurate CDW phase, which results in a significant decrease in both the phase transition temperature(T_(c)) and phase transition stiffness. We interpret the phenomenon that photoinduced hole doping, when surpassing a critical threshold value of ~ 10^(18)cm^(-3), sharply decreases the phase transition energy barrier. Our results provide new insights into controlling the CDW phase transition, paving the way for optical-controlled novel devices based on CDW materials.展开更多
Simultaneously manipulating multiple physical fields plays an important role in the increasingly complex integrated systems,aerospace equipment,biochemical productions,etc.For on-chip systems with high integration lev...Simultaneously manipulating multiple physical fields plays an important role in the increasingly complex integrated systems,aerospace equipment,biochemical productions,etc.For on-chip systems with high integration level,the precise and efficient control of the propagation of electromagnetic waves and heat fluxes simultaneously is particularly important.In this study,we propose a graphical designing method(i.e.,thermal-electromagnetic surface transformation)based on thermal-electromagnetic null medium to simultaneously control the propagation of electromagnetic waves and thermal fields according to the pre-designed paths.A thermal-electromagnetic cloak,which can create a cloaking effect on both electromagnetic waves and thermal fields simultaneously,is designed by thermal-electromagnetic surface transformation and verified by both numerical simulations and experimental measurements.The thermal-electromagnetic surface transformation proposed in this study provides a new methodology for simultaneous controlling on electromagnetic and temperature fields,and may have significant applications in improving thermal-electromagnetic compatibility problem,protecting of thermal-electromagnetic sensitive components,and improving efficiency of energy usage for complex onchip systems.展开更多
Background Early screening of cognitive function is critical to dementia treatment and care.However,traditional tests require face-to-face administration and are often limited by implementation costs and biases.Aims T...Background Early screening of cognitive function is critical to dementia treatment and care.However,traditional tests require face-to-face administration and are often limited by implementation costs and biases.Aims This study aimed to assess whether the Thoven Cognitive Self-Assessment(TCSA),a novel,innovative two-step touchscreen-based cognition assessment tool,could identify early cognitive impairment due to dementia in older adults.Methods The TCSA was administered to 61 healthy controls(HCs),46 participants with mild cognitive impairment(MCI)and 44 participants diagnosed with dementia recruited from Shanghai.Two outcome measures were generated from the TCSA test:the TCSA_(primary task)score and the TCSA_(secondary task)score.Results The total average scores in the control group for the TCSA_(primary task)and TCSA_(secondary task)were significantly higher than those in the MCI and dementia groups(TCSA_(primary task):HCs vs MCI group vs dementia group,8.58±1.76 vs 5.40±2.67 vs 2.74±2.11,F=75.40,p<0.001;TCSA_(secondary task):HCs vs MCI group vs dementia group,23.02±3.31 vs 17.95±4.93 vs 11.93±5.50,F=76.46,p<0.001).Moreover,receiver operating characteristic analysis showed that a score below 7.5 for the TCSA_(primary task)and a score below 22.5 for the TCSA_(secondary task)were indicators of MCI.Conclusions The TCSA appears to be efficacious for the detection of cognitive impairment in older adults.It demonstrates the potential for large-scale cognition screening in community service settings.展开更多
Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autop...Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy.Methods:The primary hippocampal neurons,N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy,which was analysed by Student’s two-tailed t-test.The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1(mTORC1)activity and the vacuolar H+-ATPase(v-ATPase)activity,respectively,which were analysed by One-way ANOVA with post hoc tests.The Western blotting,co-immunoprecipitation and immunofuorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations,as analysed by Student’s two-tailed t-test or One-way ANOVA with post hoc tests.The autophagosome formation was detected by immunofuorescence staining and transmission electron microscopy.The amino acids(AA)levels were detected by high performance liquid chromatography(HPLC).Results:We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits.Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1(PRD-TIA1)and this association significantly increased the intercellular level of amino acids(Leucine,P=0.0038;Glutamic acid,P=0.0348;Alanine,P=0.0037;Glycine,P=0.0104),with concordant upregulation of mTORC1 activity[phosphorylated eukaryotic translation initiation factor 4E-binding protein 1(p-4EBP1),P<0.0001;phosphorylated 70 kD ribosomal protein S6 kinase 1(p-p70S6K1),P=0.0001,phosphorylated unc-51-like autophagyactivating kinase 1(p-ULK1),P=0.0015]and inhibition of autophagosome formation[microtubuleassociated protein light chain 3 II(LC3 II),P=0.0073;LC3 puncta,P<0.0001].As expected,this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation.Importantly,we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1,downregulating the endogenous TIA1 expression by shRNA,or downregulating tau protein level by a small proteolysis targeting chimera(PROTAC)could remarkably attenuate tau-induced autophagy impairment.Conclusions:Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway,and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treat-ment and that of related tauopathies.展开更多
In maize,prolificacy,the number of ears per plant,is a trait of interest to maize breeders for breeding high grain-yielding cultivars or specialty corn,as well as being a model trait for decoding the molecular mechani...In maize,prolificacy,the number of ears per plant,is a trait of interest to maize breeders for breeding high grain-yielding cultivars or specialty corn,as well as being a model trait for decoding the molecular mechanism of maize evolution.Its genetic basis remains largely unknown.We identified a stable quantitative trait locus,qEN7,for ear number on chromosome 7 in both F2 and F2:3 populations derived from a single cross between the nonprolific inbred line Mo17 and the prolific inbred line LAN404 derived from the landrace PI217404.qEN7 explained 10.7%-11.9%of phenotypic variation,and the LAN404 allele at this locus was associated with an increase of around one ear per plant.qEN7 was confined by fine-mapping to a 0.56-Mb region containing eight annotated genes.Analysis of selection,gene expression patterns in various maize tissues,and sequence polymorphisms between the two parental lines suggested that Zm00001d020683,which encodes a putative INDETERMINATE DOMAIN(IDD)transcription factor,is the most likely candidate gene underlying qEN7.Zm00001d020683 is expressed mainly in the vegetative meristem,immature ears,and internodes and has undergone selection during maize improvement.The identification of qEN7 and the prediction of its candidate gene sheds some light on the evolution of maize ear number and provides a novel resource for breeding of multi-ear maize cultivars.展开更多
Multiplex polymerase chain reaction （PCR） has been widely used to detect Y-chromosome micredeletions, which is one of the major causes of male infertility. Both the European Academy of Andrology （EAA） and the Euro...Multiplex polymerase chain reaction （PCR） has been widely used to detect Y-chromosome micredeletions, which is one of the major causes of male infertility. Both the European Academy of Andrology （EAA） and the European Molecular Genetics Quality Network （EMQN） have recommended the use of sY84 and sY86 markers for the detection of azoospermia factor a （AZFa） microdeletion during DNA testing for male infertility. In this study, a large-scale analysis of AZF microdeletion in a total of 630 Chinese males, including healthy semen donors （n=200）, infertile males with normal sperm count （n=226） and patients with either nonobstructive azoospermia or severe oligozoospermia （n=204）, was performed. A series of nine sequence-tagged site （STS） markers from the AZF region of the Y chromosome was used to detect microdeletions. All primers were designed based on the recommendations of the National Center for Biotechnology Information. An unusually high incidence （73/630, 11.6%） of sY84-absent but sY86-present genotypes was observed in the AZFa microdeletion screening. Sequencing the sY84-flanking region revealed a total of 73 patients with sY84-absent but sY86-present genotypes have a T-to-G transversion at the fifth base from the 5＇ end of the reverse sY84 primer. These prevalent false positives, which were not only observed in infertile men, but also observed in donors, resulted from a single-nucleotide polymorphism （SNP） named rs72609647 in the targeting sequence of the reverse sY84 primer. Our study suggests that a pre-screening of existence of rs72609647 polymorphism can prevent the frequent false positive results of AZFa microdeletions detection in the infertile Chinese males. Given the SNP rs72609647 was recently found in a deep sequencing of a Chinese individual, the current EAA and EMQN standards may need to be scrutinized among different populations to avoid the potential genetic variations in the primer binding sequences.展开更多
At present the mechanical model of the interac- tion between a disc cutter and rock mainly concerns indentation experiment, linear cutting experiment and tunnel boring machine （TBM） on-site data. This is not in line...At present the mechanical model of the interac- tion between a disc cutter and rock mainly concerns indentation experiment, linear cutting experiment and tunnel boring machine （TBM） on-site data. This is not in line with the actual rock-breaking movement of the disc cutter and impedes to some extent the research on the rock-breaking mechanism, wear mechanism and design theory. Therefore, our study focuses on the interaction between the slantingly installed disc cutter and rock, developing a model in accordance with the actual rock-breaking movement. Displacement equations are established through an analysis of the velocity vector at the rock-breaking point of the disc cutter blade; the func- tional relationship between the displacement parameters at the rock-breaking point and its rectangular coordinates is established through an analysis of micro-displacement vectors at the rock-breaking point, thus leading to the geometric equations of rock deformation caused by the slantingly installed disc cutter. Considering the basically linear relationship between the cutting force of disc cutters and the rock deformation before and after the leap break of rock, we express the constitutive relations of rock deformation as generalized Hooke＇s law and analyze the effect of the slanting installa- tion angle of disc cutters on the rock-breaking force. This will, as we hope, make groundbreaking contributions to the development of the design theory and installation practice of TBM.展开更多
Attempts to minimize energy consumption of a tunnel boring machine disc cutter during the process of fragmentation have largely focused on optimizing disc- cutter spacing, as determined by the minimum specific energy ...Attempts to minimize energy consumption of a tunnel boring machine disc cutter during the process of fragmentation have largely focused on optimizing disc- cutter spacing, as determined by the minimum specific energy required for fragmentation; however, indentation tests showed that rock deforms plastically beneath the cutters. Equations for thrust were developed for both the traditional, popularly employed disc cutter and anew design based on three-dimensional theory. The respective energy consumption for penetration, rolling, and side-slip fragmentations were obtained. A change in disc-cutter fragmentation angles resulted in a change in the nature of the interaction between the cutter and rock, which lowered the specific energy of fragmentation. During actual field excavations to the same penetration length, the combined energy consumption for fragmentation using the newly designed cutters was 15% lower than that when using the traditional design. This paper presents a theory for energy saving in tunnel boring machines. Investigation results showed that the disc cutters designed using this theory were more durable than traditional designs, and effectively lowered the energy consumption.展开更多
Objective To evaluate the clinical impact of whole body diffusion weighted imaging （WB-DWI） on diagnosis and staging of malignant lymphoma. Methods Thirty-one patients with suspected lymphadenopathy were enrolled. ...Objective To evaluate the clinical impact of whole body diffusion weighted imaging （WB-DWI） on diagnosis and staging of malignant lymphoma. Methods Thirty-one patients with suspected lymphadenopathy were enrolled. WB-DWI was performed by using short TI inversion recovery echo-planar imaging sequence with free breathing and built-in body coil. Axial T2- weighted imaging images of the same location were used as reference. The results of WB-DWI were compared with pathological results and other imaging modalities. The mean apparent diffusion coefficient （ADC） values of different kinds of lymph nodes were compared. Results WB-DWI was positive in all 18 cases with lymphoma, 5 cases with metastatic lymph nodes and 4 of 8 eases with benign lymphadenopathy. The mean ADC value of lymphomatous, metastatic and benign lymph nodes was （0.87 ± 0.17） × 10^3, （0.98± 0.09） × 10^3 and （1.20 ± 0.10） × 10^3 mm^2/s. There was significant difference in ADC value between benign lymph nodes and other two groups （P 〈 0.01）. The sensitivity, specificity and accuracy of WB-DWI in diagnosis of lymphoma were 100% （18/18）, 30.8% （4/13） and 71.0% （22/31）. When an ADC value of 1.08 × 10^-3 mm^2/s was used as the threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with sensitivity of 87.8% and specificity of 91.3%. Sixteen of eighteen cases （88.9%） of lymphoma were accurately staged in accordance with clinical staging. Conclusions WB-DWI is a sensitive, but less specific technique for diagnosis of lymphoma. It is difficult to differentiate lymphnmatous from metastatic lymph nodes using WB-DWI. However, it is a valuable imaging modality for staging of patients with malignant lymphoma.展开更多
Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods Twenty-four patients (mean age 37.9 years old) with proved cer...Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods Twenty-four patients (mean age 37.9 years old) with proved cervical cancer by cervical biopsy and 24 female patients with other suspected pelvic abnormalities received preoperative body DWI scan. Results of body DWI were compared with pathological findings. The apparent diffusion coefficient (ADC) values of normal cervix and different pathological types of cervical cancer were compared. ADC value of normal or inflammatory lymph nodes was also compared with that of metastatic ones. Student's t test was used for statistical analysis. Results There were 5 adenocarcinomas and 19 epitheliomas showed with biopsy results, and DWI showed 21 cervical lesions out of them (87.5%). ADC values of the normal cervix (n = 24), epithelioma (n = 19), and adenocar- cinoma (n = 5) were (1.73 ± 0.31) ×10-3, (0.88 ± 0.22) ×10-3, and (1.08 ± 0.12) ×10-3 mm2/s, respectively. Statistical analysis showed significant difference in ADC value between normal cervical tissue and either tumor tissues (both P < 0.01). In patients had lymphadenectomy (n = 24), totally 67 lymph nodes including 16 metastatic lymph nodes were pathologically analyzed, and DWI showed 66 (98.5%) out of them. ADC values of normal/inflammatory and metastatic lymph nodes were (1.07 ± 0.16) ×10-3 and (0.77 ± 0.13) ×10-3 mm2/s (P < 0.01). Receiver operating characteristic (ROC) curve of ADC value of metastatic lymph node showed that area under curve was 0.961. Conclusions ADC value in cervical carcinoma is lower than that in normal cervix, and ADC may have predictive value in subtype discrimination. ADC value may improve the preoperative characterization of lymph node metastasis. And at least abdominal and pelvic DWI scan is suggested for N staging evaluation in such patients.展开更多
Predicting the cutter consumption and the exact time to replace the worn-out cutters in tunneling projects constructed with tunnel boring machine(TBM) is always a challenging issue. In this paper, we focus on the anal...Predicting the cutter consumption and the exact time to replace the worn-out cutters in tunneling projects constructed with tunnel boring machine(TBM) is always a challenging issue. In this paper, we focus on the analyses of cutter motion in the rock breaking process and trajectory of rock breaking point on the cutter edge in rocks. The analytical expressions of the length of face along which the breaking point moves and the length of spiral trajectory of the maximum penetration point are derived. Through observation of rock breaking process of disc cutters as well as analysis of disc rock interaction, the following concepts are proposed: the arc length theory of predicting wear extent of inner and center cutters, and the spiral theory of predicting wear extent of gage and transition cutters. Data obtained from5621 m-long Qinling tunnel reveal that among 39 disc cutters, the relative errors between cumulatively predicted and measured wear values for nine cutters are larger than 20%, while approximately 76.9% of total cutters have the relative errors less than 20%. The proposed method could offer a new attempt to predict the disc cutter's wear extent and changing time.展开更多
Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolle...Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolled in our study. All the patients received the whole body DWI and bone scintigraphy scan within 1 week. The magnetic resonance (MR) examination was performed on 3.0T MR scanner using embedded body coil. The images were reviewed separately by two radiologists and two nuclear medicine physicians, who were blinded to the results of the other imaging modality. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the two techniques for detecting bone metastasis were analyzed. Results A total of 181 metastatic lesions in 77 regions of 34 patients were detected by whole body DWI, and 167 metastatic lesions in 76 regions of 31 patients were identified by bone scintigraphy. The patient-based sensitivity and PPV of whole body DWI and bone scintigraphy were similar (89.5% vs. 81.6%, 97.1% vs. 91.2%), whereas, the patient-based specificity and NPV of whole body DWI were obviously higher than those of bone scintigraphy (85.7% vs. 57.1%, 60.0% vs. 36.4%). Ten regions negative in scintigraphy but positive in whole body DWI, mainly located in spine, pelvis, and femur; nine regions only detected by scintigraphy, mainly located in skull, sternum, clavicle, and scapula. The region-based sensitivity and specificity of whole body DWI were slightly higher than those of bone scintigraphy (89.5% vs. 88.4%, 95.6% vs. 87.6%). Conclusion Whole body DWI reveals excellent concordance with bone scintigraphy regarding detection of bone metastasis, and the two techniques are complementary for each other.展开更多
Objective To investigate the feasibility of magnetic resonance （MR） diffusion weighted imaging （DWI） for evaluation of radiotherapeutic effects on rabbit VX2 tumor model. Methods Sixteen New Zealand white rabbits...Objective To investigate the feasibility of magnetic resonance （MR） diffusion weighted imaging （DWI） for evaluation of radiotherapeutic effects on rabbit VX2 tumor model. Methods Sixteen New Zealand white rabbits received a subcutaneous implantation of VX2 tumor cell suspension 0.5 mL （4× 10^7 ceUs/mL） in their right thighs to set up tumor model. And 2 weeks later they were randomly divided into therapy group （Group T, n = 10） and control group （Group C, n = 6）. Group T received radiotherapy at a single dose of 10 Gy. MR imaging （MRI） scan including short TI inversion recovery echo-planar imaging DWI, T1-weighted imaging （T1WI） and T2-weighted imaging （T2WI） sequences were performed 1 day prior to as well as 1 day, 2 days, 3 days and 7 days after radiotherapy. Group C received only MRI scan at the same time points without any treatment. MRI appearance on T2WI, TlWI, and DWI images was compared and tumor volume was calculated. Apparent diffusion coefficient （ADC） values of the tumor were evaluated in all cases. HE staining was used for pathological study. Results Necrosis （n = 8） and hemorrhage （n = 2） were seen gradually on T2WI and T1WI images of Group T after time point of day 2 after irradiation. In Group C, no obvious necrosis was found until day 7. There was no significant difference in tumor volume between the two groups before radiotherapy. After radiotherapy, tumors in Group T showed a gradual growth but not as obvious as Group C. There was a significant difference in tumor volume between the two groups from day 2 on （P 〈 0.05）. ADC value changed dramatically fight from the 1st day after radiotherapy in Group T [（0.99 ± 0.15） ×10^-3 mm^2/s for 1 day before radiotherapy, （1.23 ± 0.08） ×10^-3 , （1.45 ± 0.07） ×10^-3 , （1.63 ± 0.06） ×10^-3 , and （2.02 ± 0.18） ×10^-3 mm^2 for day 1, 2, 3, and 7]; and ADC value had no significant changes after radiotherapy in Group C except day 7 [（1.07±0.08） ×10^-3 mm^2 for 1 day before radiotherapy, （1.03 ± 0.04）×10^-3 , （1.05 ± 0.02）×10^-3 , （1.05 ± 0.05） ×10^-3 , and （0.95 ± 0.07） ×10^-3 mm^2 for day 1, 2, 3, and 7]. There was significant difference in ADC value between the two groups for each time point after radiotherapy （P 〈 0.01）. Pathological study showed that the number of viable tumor cells in Group T decreased 1 day after radiotherapy, and the inflammatory cell infiltration was marked and almost all viable tumor cells disappeared by day 7 after radiotherapy. Conclusions DWI is a new promising technique for monitoring radiotherapy outcomes. ADC value may give a prior clue on physiological changes of radiotherapy before routine MRI could tell.展开更多
This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive ...This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive noise as α-stable distribution, new methods which combine the sparse signal representation technique and fractional lower order statistics theory are proposed. In the new algorithms, the fractional lower order statistics vectors of the array output signal are sparsely represented on an overcomplete basis and the DOAs can be effectively estimated by searching the sparsest coefficients. To enhance the robustness performance of the proposed algorithms,the improved algorithms are advanced by eliminating the fractional lower order statistics of the noise from the fractional lower order statistics vector of the array output through a linear transformation. Simulation results have shown the effectiveness of the proposed methods for a wide range of highly impulsive environments.展开更多
Objective To evaluate the values of whole body diffusion weighted imaging （DWI） in screenmg pnmary unknown tumor in patients with metastases. Methods Totally, 34 patients with metastases of primary unknown tumors w...Objective To evaluate the values of whole body diffusion weighted imaging （DWI） in screenmg pnmary unknown tumor in patients with metastases. Methods Totally, 34 patients with metastases of primary unknown tumors were scanned with whole body DWI, and conventional magnetic resonance （MR） imaging was performed if suspected lesions were detected. All the metastases including 27 cases of osseous metastases, 2 brain metastases, 2 liver metastases, 1 pulmonary multiple metastasis, 1 neck metastasis and 1 malignant ascites, were diagnosed by computed tomography, single photon emission computed tomography, or MR imaging. For the proven primary tumors diagnosed by biopsy or pathology of surgical specimens, apparent diffusion coefficient （ADC） values of the primary and metastatic lesions were measured respectively. The sensitivity and specificity of this technique for screening primary tumors were cvaluated. Results We found 24 cases with suspected primary lesions, in which 23 lesions were proved to be primary tumors, and 1 was proved to be benign lesion. And no definite primary lesion was found in 10 cases on whole body DWI, but in which 1 case was diagnosed with primary tumor by biopsy later, and the other 9 cases remained unknown within follow-up of over halfa year. The difference was not significant in ADC values between primary and metastatic lesions （P〉0.05）. The sensitivity and specificity of whole body DWI for searching primary tumors was 95.8% and 90.0%, respectively. Conclusion Combined with conventional MR scanning, whole body DWI can help to search primary lesions of patients with metastases.展开更多
Objective To evaluate the value of whole-body diffusion weighted imaging （WB-DWI） on detection of malignant metastasis. Methods Forty-six patients with malignant tumors underwent WB-DWI examinations between April 20...Objective To evaluate the value of whole-body diffusion weighted imaging （WB-DWI） on detection of malignant metastasis. Methods Forty-six patients with malignant tumors underwent WB-DWI examinations between April 2007 and August 2007 in our hospital. Before WB-DWI examination, the primary cancers of all the patients were confirmed by pathology, and the TNM-stage was assessed with conventional magnetic resonance imaging （MRI） or computed tomography （CT）. WB-DWI was performed using short TI inversion recovery echo-planar imaging （STIR-EPI） sequence. Abnormal high signal intensities on WB-DWI were considered as metastases. The results of WB-DWI were compared with other imaging modalities. For the assessment of the diagnostic capability of WB-DWI, WB-DWI were compared with CT for demonstrating mediastinal lymph node metastases and lung metastases, and with conventional MRI for demonstrating metastases in other locations. Results WB-DWI demonstrated 143 focuses, 14 routine imaging. The number of bone metastases depicted of which were diagnosed to be benign lesions in on WB-DWI and routine imaging was 85 and 86; lymph node metastases was 17 and 18; liver metastases was 14 and 14; lung metastases was 4 and 8; and brain metastases was 6 and 8, respectively. WB-DWI failed to detect 12 metastatic lesions including 3 osteoplastic bone metastases, 4 lung metastases, 3 mediastinal lymph node metastases, and 2 brain metastases Four metastatic lesions including 2 deltopectoral lymph nodes and 2 rib metastases were detected with WB-DWI alone, all of which evolved greatly during clinical follow-up for more than 6 months. WB-DWI had higher detection rates for metastatic lesions in liver, bone, and lymph nodes than those in lung and brain （ X^2=30, P〈0.001）. Conclusions WB-DWI could detect most of metastatic lesions that were diagnosed with conventional MRI and CT. The limitations of WB-DWI might be had high false-positive rate and low efficiency in detecting mecliastinal lymph node, brain, and lung metastases.展开更多
Distinctive superconducting behaviors between bulk and monolayer FeSe make it challenging to obtain a unified picture of all FeSe-based superconductors.We investigate the ultrafast quasiparticle(QP)dynamics of an inte...Distinctive superconducting behaviors between bulk and monolayer FeSe make it challenging to obtain a unified picture of all FeSe-based superconductors.We investigate the ultrafast quasiparticle(QP)dynamics of an intercalated superconductor(Li1-xFex)OHFe1-ySe,which is a bulk crystal but shares a similar electronic structure with single-layer FeSe on SrTiO3.We obtain the electron-phonon coupling(EPC)constant(0.22±0.04),which well bridges that of bulk FeSe crystal and single-layer FeSe on SrTiO3.Significantly,we find that such a positive correlation betweenλA1 g and superconducting Tc holds among all known FeSe-based superconductors,even in line with reported FeAs-based superconductors.Our observation indicates possible universal role of EPC in the superconductivity of all known categories of iron-based superconductors,which is a critical step towards achieving a unified superconducting mechanism for all iron-based superconductors.展开更多
基金supported by the National Natural Science Foundation of China(82271645)National Key Research and Development Program of China(2021YFC2700200 to F.S.)。
文摘Meiosis is a highly complex process significantly influenced by transcriptional regulation.However,studies on the mechanisms that govern transcriptomic changes during meiosis,especially in prophase I,are limited.Here,we performed single-cell ATAC-seq of human testis tissues and observed reprogramming during the transition from zygotene to pachytene spermatocytes.This event,conserved in mice,involved the deactivation of genes associated with meiosis after reprogramming and the activation of those related to spermatogenesis before their functional onset.Furthermore,we identified 282 transcriptional regulators(TRs)that underwent activation or deactivation subsequent to this process.Evidence suggested that physical contact signals from Sertoli cells may regulate these TRs in spermatocytes,while secreted ENHO signals may alter metabolic patterns in these cells.Our results further indicated that defective transcriptional reprogramming may be associated with non-obstructive azoospermia(NOA).This study revealed the importance of both physical contact and secreted signals between Sertoli cells and germ cells in meiotic progression.
基金financially supported by the National Natural Science Foundation of China(No.51804232)Beijing Municipal Natural Science Foundation,China(No.2212041)partially supported by the Interdisciplinary Research Project for Young Teachers of USTB,China(Fundamental Research Funds for the Central Universities,China)(No.FRF-IDRY-20-020)。
基金supported by Beijing Natural Science Foundation (No. 2212049)NSF of China (No. 11974407)+1 种基金CAS Project for Young Scientists in Basic Research (No. YSBR-030)the Youth Innovation Promotion Association of CAS (No. 2020007)
文摘Applying pressure has been evidenced as an effective method to control the properties of semiconductors,owing to its capability to modify the band configuration around Fermi energy.Correspondingly,structural evolutions under external pres-sures are required to analyze the mechanisms.Herein high-pressure structure of a magnetic doped semiconductor Ba(Zn_(0.95)Mn_(0.05))_(2)As_(2)is studied with combination of in-situ synchrotron X-ray diffractions and diamond anvil cells.The materials become ferromagnetic with Curie temperature of 105 K after further 20%K doping.The title material undergoes an isostruc-tural phase transition at around 19 GPa.Below the transition pressure,it is remarkable to find lengthening of Zn/Mn-As bond within Zn/MnAs layers,since chemical bonds are generally shortened with applying pressures.Accompanied with the bond stretch,interlayer As-As distances become shorter and the As-As dimers form after the phase transition.With further compres-sion,Zn/Mn-As bond becomes shortened due to the recovery of isotropic compression on the Zn/MnAs layers.
基金supported by the National Key Research and Development Program of China (Grant No. 2021YFA1400201)the CAS Project for Young Scientists in Basic Research (Grant No. YSBR059)+5 种基金the Beijing Natural Science Foundation (Grant No. 4191003)the National Natural Science Foundation of China (Grant No. 11774408)the Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant No. GJJSTD20200005)the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos. XDB36000000 and XDB30000000)the International Partnership Program of Chinese Academy of Sciences (Grant No. GJHZ1826)CAS Interdisciplinary Innovation Team。
文摘Controlling collective electronic states hold great promise for development of innovative devices. Here, we experimentally detect the modification of the charge density wave(CDW) phase transition within a 1T-TaS_(2) layer in a WS_(2)/1T-TaS_(2) heterostructure using time-resolved ultrafast spectroscopy. Laser-induced charge transfer doping strongly suppresses the commensurate CDW phase, which results in a significant decrease in both the phase transition temperature(T_(c)) and phase transition stiffness. We interpret the phenomenon that photoinduced hole doping, when surpassing a critical threshold value of ~ 10^(18)cm^(-3), sharply decreases the phase transition energy barrier. Our results provide new insights into controlling the CDW phase transition, paving the way for optical-controlled novel devices based on CDW materials.
基金supported by the National Natural Science Foundation of China (Nos. 61971300, 12274317, 12374277, 61905208)Open Foundation of China-Belarus Belt and Road Joint Laboratory on Electromagnetic Environment Effect (No. ZBKF2022031202)+1 种基金Scientific and Technological Innovation Programs (STIP) of Higher Education Institutions in Shanxi (Nos. 2019L0159 and 2019L0146)2022 University Outstanding Youth Foundation of Taiyuan University of Technology
文摘Simultaneously manipulating multiple physical fields plays an important role in the increasingly complex integrated systems,aerospace equipment,biochemical productions,etc.For on-chip systems with high integration level,the precise and efficient control of the propagation of electromagnetic waves and heat fluxes simultaneously is particularly important.In this study,we propose a graphical designing method(i.e.,thermal-electromagnetic surface transformation)based on thermal-electromagnetic null medium to simultaneously control the propagation of electromagnetic waves and thermal fields according to the pre-designed paths.A thermal-electromagnetic cloak,which can create a cloaking effect on both electromagnetic waves and thermal fields simultaneously,is designed by thermal-electromagnetic surface transformation and verified by both numerical simulations and experimental measurements.The thermal-electromagnetic surface transformation proposed in this study provides a new methodology for simultaneous controlling on electromagnetic and temperature fields,and may have significant applications in improving thermal-electromagnetic compatibility problem,protecting of thermal-electromagnetic sensitive components,and improving efficiency of energy usage for complex onchip systems.
基金This study was funded by Key R&D Program of China(Grant number:2017YFC1310500)Shanghai Municipal Health Commission project(Grant number:202040500)Shanghai public health projects(Grant number:GWV-9.2)。
文摘Background Early screening of cognitive function is critical to dementia treatment and care.However,traditional tests require face-to-face administration and are often limited by implementation costs and biases.Aims This study aimed to assess whether the Thoven Cognitive Self-Assessment(TCSA),a novel,innovative two-step touchscreen-based cognition assessment tool,could identify early cognitive impairment due to dementia in older adults.Methods The TCSA was administered to 61 healthy controls(HCs),46 participants with mild cognitive impairment(MCI)and 44 participants diagnosed with dementia recruited from Shanghai.Two outcome measures were generated from the TCSA test:the TCSA_(primary task)score and the TCSA_(secondary task)score.Results The total average scores in the control group for the TCSA_(primary task)and TCSA_(secondary task)were significantly higher than those in the MCI and dementia groups(TCSA_(primary task):HCs vs MCI group vs dementia group,8.58±1.76 vs 5.40±2.67 vs 2.74±2.11,F=75.40,p<0.001;TCSA_(secondary task):HCs vs MCI group vs dementia group,23.02±3.31 vs 17.95±4.93 vs 11.93±5.50,F=76.46,p<0.001).Moreover,receiver operating characteristic analysis showed that a score below 7.5 for the TCSA_(primary task)and a score below 22.5 for the TCSA_(secondary task)were indicators of MCI.Conclusions The TCSA appears to be efficacious for the detection of cognitive impairment in older adults.It demonstrates the potential for large-scale cognition screening in community service settings.
基金supported by grants from the Natural Science Foundation of China(91949205,31730035,81721005)the Science and Technology Committee of China(2016YFC1305800)+1 种基金the Special Project of Technological Innovation of Hubei Province(2018ACA142)Guangdong Provincial Key S&T Program(2018B030336001)。
文摘Background:Autophagy dysfunction plays a crucial role in tau accumulation and neurodegeneration in Alzheimer’s disease(AD).This study aimed to investigate whether and how the accumulating tau may in turn affect autophagy.Methods:The primary hippocampal neurons,N2a and HEK293T cells with tau overexpression were respectively starved and treated with vinblastine to study the effects of tau on the initiating steps of autophagy,which was analysed by Student’s two-tailed t-test.The rapamycin and concanamycin A were employed to inhibit the mammalian target of rapamycin kinase complex 1(mTORC1)activity and the vacuolar H+-ATPase(v-ATPase)activity,respectively,which were analysed by One-way ANOVA with post hoc tests.The Western blotting,co-immunoprecipitation and immunofuorescence staining were conducted to gain insight into the mechanisms underlying the tau effects of mTORC1 signaling alterations,as analysed by Student’s two-tailed t-test or One-way ANOVA with post hoc tests.The autophagosome formation was detected by immunofuorescence staining and transmission electron microscopy.The amino acids(AA)levels were detected by high performance liquid chromatography(HPLC).Results:We observed that overexpressing human full-length wild-type tau to mimic AD-like tau accumulation induced autophagy deficits.Further studies revealed that the increased tau could bind to the prion-related domain of T cell intracellular antigen 1(PRD-TIA1)and this association significantly increased the intercellular level of amino acids(Leucine,P=0.0038;Glutamic acid,P=0.0348;Alanine,P=0.0037;Glycine,P=0.0104),with concordant upregulation of mTORC1 activity[phosphorylated eukaryotic translation initiation factor 4E-binding protein 1(p-4EBP1),P<0.0001;phosphorylated 70 kD ribosomal protein S6 kinase 1(p-p70S6K1),P=0.0001,phosphorylated unc-51-like autophagyactivating kinase 1(p-ULK1),P=0.0015]and inhibition of autophagosome formation[microtubuleassociated protein light chain 3 II(LC3 II),P=0.0073;LC3 puncta,P<0.0001].As expected,this tau-induced deficit of autophagosome formation in turn aggravated tau accumulation.Importantly,we also found that blocking TIA1 and tau interaction by overexpressing PRD-TIA1,downregulating the endogenous TIA1 expression by shRNA,or downregulating tau protein level by a small proteolysis targeting chimera(PROTAC)could remarkably attenuate tau-induced autophagy impairment.Conclusions:Our findings reveal that AD-like tau accumulation inhibits autophagosome formation and induces autophagy deficits by activating the TIA1/amino acid/mTORC1 pathway,and thus this work reveals new insight into tau-associated neurodegeneration and provides evidence supporting the use of new therapeutic targets for AD treat-ment and that of related tauopathies.
基金supported by the National Natural Science Foundation of China(91935302)the Beijing Outstanding Young Scientist Program(BJJWZYJH01201910019026)the Chinese Universities Scientific Fund(2022TC035).
文摘In maize,prolificacy,the number of ears per plant,is a trait of interest to maize breeders for breeding high grain-yielding cultivars or specialty corn,as well as being a model trait for decoding the molecular mechanism of maize evolution.Its genetic basis remains largely unknown.We identified a stable quantitative trait locus,qEN7,for ear number on chromosome 7 in both F2 and F2:3 populations derived from a single cross between the nonprolific inbred line Mo17 and the prolific inbred line LAN404 derived from the landrace PI217404.qEN7 explained 10.7%-11.9%of phenotypic variation,and the LAN404 allele at this locus was associated with an increase of around one ear per plant.qEN7 was confined by fine-mapping to a 0.56-Mb region containing eight annotated genes.Analysis of selection,gene expression patterns in various maize tissues,and sequence polymorphisms between the two parental lines suggested that Zm00001d020683,which encodes a putative INDETERMINATE DOMAIN(IDD)transcription factor,is the most likely candidate gene underlying qEN7.Zm00001d020683 is expressed mainly in the vegetative meristem,immature ears,and internodes and has undergone selection during maize improvement.The identification of qEN7 and the prediction of its candidate gene sheds some light on the evolution of maize ear number and provides a novel resource for breeding of multi-ear maize cultivars.
基金ACKNOWLEDGMENTS This research was supported by the Major State Basic Research Development Program of China （973 Program, Noso 2006GB504005 and 2009CB941700）, the National Natural Science Foundation of China （No. 30872765） and the Basic Research Key Program of Shanghai （10]C1410800）. Shi-Wei Duan is sponsored partly by the K. C. Wong Magna Fund of Ningbo University. Wethank Dr Ching-Ling Chen for kind suggestions regarding English in drafting this paper.
文摘Multiplex polymerase chain reaction （PCR） has been widely used to detect Y-chromosome micredeletions, which is one of the major causes of male infertility. Both the European Academy of Andrology （EAA） and the European Molecular Genetics Quality Network （EMQN） have recommended the use of sY84 and sY86 markers for the detection of azoospermia factor a （AZFa） microdeletion during DNA testing for male infertility. In this study, a large-scale analysis of AZF microdeletion in a total of 630 Chinese males, including healthy semen donors （n=200）, infertile males with normal sperm count （n=226） and patients with either nonobstructive azoospermia or severe oligozoospermia （n=204）, was performed. A series of nine sequence-tagged site （STS） markers from the AZF region of the Y chromosome was used to detect microdeletions. All primers were designed based on the recommendations of the National Center for Biotechnology Information. An unusually high incidence （73/630, 11.6%） of sY84-absent but sY86-present genotypes was observed in the AZFa microdeletion screening. Sequencing the sY84-flanking region revealed a total of 73 patients with sY84-absent but sY86-present genotypes have a T-to-G transversion at the fifth base from the 5＇ end of the reverse sY84 primer. These prevalent false positives, which were not only observed in infertile men, but also observed in donors, resulted from a single-nucleotide polymorphism （SNP） named rs72609647 in the targeting sequence of the reverse sY84 primer. Our study suggests that a pre-screening of existence of rs72609647 polymorphism can prevent the frequent false positive results of AZFa microdeletions detection in the infertile Chinese males. Given the SNP rs72609647 was recently found in a deep sequencing of a Chinese individual, the current EAA and EMQN standards may need to be scrutinized among different populations to avoid the potential genetic variations in the primer binding sequences.
基金supported by the National Natural Science Foundation of China(51075147)863 Project(2012AA041803)
文摘At present the mechanical model of the interac- tion between a disc cutter and rock mainly concerns indentation experiment, linear cutting experiment and tunnel boring machine （TBM） on-site data. This is not in line with the actual rock-breaking movement of the disc cutter and impedes to some extent the research on the rock-breaking mechanism, wear mechanism and design theory. Therefore, our study focuses on the interaction between the slantingly installed disc cutter and rock, developing a model in accordance with the actual rock-breaking movement. Displacement equations are established through an analysis of the velocity vector at the rock-breaking point of the disc cutter blade; the func- tional relationship between the displacement parameters at the rock-breaking point and its rectangular coordinates is established through an analysis of micro-displacement vectors at the rock-breaking point, thus leading to the geometric equations of rock deformation caused by the slantingly installed disc cutter. Considering the basically linear relationship between the cutting force of disc cutters and the rock deformation before and after the leap break of rock, we express the constitutive relations of rock deformation as generalized Hooke＇s law and analyze the effect of the slanting installa- tion angle of disc cutters on the rock-breaking force. This will, as we hope, make groundbreaking contributions to the development of the design theory and installation practice of TBM.
基金Supported by National Natural Science Foundation of China(Grant No.51475163)National Hi-tech Research and Development Program of China(863 Program,Grant No.2012AA041803)
文摘Attempts to minimize energy consumption of a tunnel boring machine disc cutter during the process of fragmentation have largely focused on optimizing disc- cutter spacing, as determined by the minimum specific energy required for fragmentation; however, indentation tests showed that rock deforms plastically beneath the cutters. Equations for thrust were developed for both the traditional, popularly employed disc cutter and anew design based on three-dimensional theory. The respective energy consumption for penetration, rolling, and side-slip fragmentations were obtained. A change in disc-cutter fragmentation angles resulted in a change in the nature of the interaction between the cutter and rock, which lowered the specific energy of fragmentation. During actual field excavations to the same penetration length, the combined energy consumption for fragmentation using the newly designed cutters was 15% lower than that when using the traditional design. This paper presents a theory for energy saving in tunnel boring machines. Investigation results showed that the disc cutters designed using this theory were more durable than traditional designs, and effectively lowered the energy consumption.
文摘Objective To evaluate the clinical impact of whole body diffusion weighted imaging （WB-DWI） on diagnosis and staging of malignant lymphoma. Methods Thirty-one patients with suspected lymphadenopathy were enrolled. WB-DWI was performed by using short TI inversion recovery echo-planar imaging sequence with free breathing and built-in body coil. Axial T2- weighted imaging images of the same location were used as reference. The results of WB-DWI were compared with pathological results and other imaging modalities. The mean apparent diffusion coefficient （ADC） values of different kinds of lymph nodes were compared. Results WB-DWI was positive in all 18 cases with lymphoma, 5 cases with metastatic lymph nodes and 4 of 8 eases with benign lymphadenopathy. The mean ADC value of lymphomatous, metastatic and benign lymph nodes was （0.87 ± 0.17） × 10^3, （0.98± 0.09） × 10^3 and （1.20 ± 0.10） × 10^3 mm^2/s. There was significant difference in ADC value between benign lymph nodes and other two groups （P 〈 0.01）. The sensitivity, specificity and accuracy of WB-DWI in diagnosis of lymphoma were 100% （18/18）, 30.8% （4/13） and 71.0% （22/31）. When an ADC value of 1.08 × 10^-3 mm^2/s was used as the threshold value for differentiating malignant from benign lymph nodes, the best results were obtained with sensitivity of 87.8% and specificity of 91.3%. Sixteen of eighteen cases （88.9%） of lymphoma were accurately staged in accordance with clinical staging. Conclusions WB-DWI is a sensitive, but less specific technique for diagnosis of lymphoma. It is difficult to differentiate lymphnmatous from metastatic lymph nodes using WB-DWI. However, it is a valuable imaging modality for staging of patients with malignant lymphoma.
文摘Objective To evaluate the clinical impact of body diffusion weighted imaging (DWI) on the diagnosis and preoperative N staging of cervical cancer. Methods Twenty-four patients (mean age 37.9 years old) with proved cervical cancer by cervical biopsy and 24 female patients with other suspected pelvic abnormalities received preoperative body DWI scan. Results of body DWI were compared with pathological findings. The apparent diffusion coefficient (ADC) values of normal cervix and different pathological types of cervical cancer were compared. ADC value of normal or inflammatory lymph nodes was also compared with that of metastatic ones. Student's t test was used for statistical analysis. Results There were 5 adenocarcinomas and 19 epitheliomas showed with biopsy results, and DWI showed 21 cervical lesions out of them (87.5%). ADC values of the normal cervix (n = 24), epithelioma (n = 19), and adenocar- cinoma (n = 5) were (1.73 ± 0.31) ×10-3, (0.88 ± 0.22) ×10-3, and (1.08 ± 0.12) ×10-3 mm2/s, respectively. Statistical analysis showed significant difference in ADC value between normal cervical tissue and either tumor tissues (both P < 0.01). In patients had lymphadenectomy (n = 24), totally 67 lymph nodes including 16 metastatic lymph nodes were pathologically analyzed, and DWI showed 66 (98.5%) out of them. ADC values of normal/inflammatory and metastatic lymph nodes were (1.07 ± 0.16) ×10-3 and (0.77 ± 0.13) ×10-3 mm2/s (P < 0.01). Receiver operating characteristic (ROC) curve of ADC value of metastatic lymph node showed that area under curve was 0.961. Conclusions ADC value in cervical carcinoma is lower than that in normal cervix, and ADC may have predictive value in subtype discrimination. ADC value may improve the preoperative characterization of lymph node metastasis. And at least abdominal and pelvic DWI scan is suggested for N staging evaluation in such patients.
基金supported by the National Natural Science Foundation of China(Grant No.51475163)the National Hightech R&D Program of China(Grant No.2012AA041803)
文摘Predicting the cutter consumption and the exact time to replace the worn-out cutters in tunneling projects constructed with tunnel boring machine(TBM) is always a challenging issue. In this paper, we focus on the analyses of cutter motion in the rock breaking process and trajectory of rock breaking point on the cutter edge in rocks. The analytical expressions of the length of face along which the breaking point moves and the length of spiral trajectory of the maximum penetration point are derived. Through observation of rock breaking process of disc cutters as well as analysis of disc rock interaction, the following concepts are proposed: the arc length theory of predicting wear extent of inner and center cutters, and the spiral theory of predicting wear extent of gage and transition cutters. Data obtained from5621 m-long Qinling tunnel reveal that among 39 disc cutters, the relative errors between cumulatively predicted and measured wear values for nine cutters are larger than 20%, while approximately 76.9% of total cutters have the relative errors less than 20%. The proposed method could offer a new attempt to predict the disc cutter's wear extent and changing time.
文摘Objective To evaluate the feasibility of whole body diffusion weighted imaging (DWI) in bone metastasis detection using bone scintigraphy as comparison. Methods Forty-five patients with malignancy history were enrolled in our study. All the patients received the whole body DWI and bone scintigraphy scan within 1 week. The magnetic resonance (MR) examination was performed on 3.0T MR scanner using embedded body coil. The images were reviewed separately by two radiologists and two nuclear medicine physicians, who were blinded to the results of the other imaging modality. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the two techniques for detecting bone metastasis were analyzed. Results A total of 181 metastatic lesions in 77 regions of 34 patients were detected by whole body DWI, and 167 metastatic lesions in 76 regions of 31 patients were identified by bone scintigraphy. The patient-based sensitivity and PPV of whole body DWI and bone scintigraphy were similar (89.5% vs. 81.6%, 97.1% vs. 91.2%), whereas, the patient-based specificity and NPV of whole body DWI were obviously higher than those of bone scintigraphy (85.7% vs. 57.1%, 60.0% vs. 36.4%). Ten regions negative in scintigraphy but positive in whole body DWI, mainly located in spine, pelvis, and femur; nine regions only detected by scintigraphy, mainly located in skull, sternum, clavicle, and scapula. The region-based sensitivity and specificity of whole body DWI were slightly higher than those of bone scintigraphy (89.5% vs. 88.4%, 95.6% vs. 87.6%). Conclusion Whole body DWI reveals excellent concordance with bone scintigraphy regarding detection of bone metastasis, and the two techniques are complementary for each other.
文摘Objective To investigate the feasibility of magnetic resonance （MR） diffusion weighted imaging （DWI） for evaluation of radiotherapeutic effects on rabbit VX2 tumor model. Methods Sixteen New Zealand white rabbits received a subcutaneous implantation of VX2 tumor cell suspension 0.5 mL （4× 10^7 ceUs/mL） in their right thighs to set up tumor model. And 2 weeks later they were randomly divided into therapy group （Group T, n = 10） and control group （Group C, n = 6）. Group T received radiotherapy at a single dose of 10 Gy. MR imaging （MRI） scan including short TI inversion recovery echo-planar imaging DWI, T1-weighted imaging （T1WI） and T2-weighted imaging （T2WI） sequences were performed 1 day prior to as well as 1 day, 2 days, 3 days and 7 days after radiotherapy. Group C received only MRI scan at the same time points without any treatment. MRI appearance on T2WI, TlWI, and DWI images was compared and tumor volume was calculated. Apparent diffusion coefficient （ADC） values of the tumor were evaluated in all cases. HE staining was used for pathological study. Results Necrosis （n = 8） and hemorrhage （n = 2） were seen gradually on T2WI and T1WI images of Group T after time point of day 2 after irradiation. In Group C, no obvious necrosis was found until day 7. There was no significant difference in tumor volume between the two groups before radiotherapy. After radiotherapy, tumors in Group T showed a gradual growth but not as obvious as Group C. There was a significant difference in tumor volume between the two groups from day 2 on （P 〈 0.05）. ADC value changed dramatically fight from the 1st day after radiotherapy in Group T [（0.99 ± 0.15） ×10^-3 mm^2/s for 1 day before radiotherapy, （1.23 ± 0.08） ×10^-3 , （1.45 ± 0.07） ×10^-3 , （1.63 ± 0.06） ×10^-3 , and （2.02 ± 0.18） ×10^-3 mm^2 for day 1, 2, 3, and 7]; and ADC value had no significant changes after radiotherapy in Group C except day 7 [（1.07±0.08） ×10^-3 mm^2 for 1 day before radiotherapy, （1.03 ± 0.04）×10^-3 , （1.05 ± 0.02）×10^-3 , （1.05 ± 0.05） ×10^-3 , and （0.95 ± 0.07） ×10^-3 mm^2 for day 1, 2, 3, and 7]. There was significant difference in ADC value between the two groups for each time point after radiotherapy （P 〈 0.01）. Pathological study showed that the number of viable tumor cells in Group T decreased 1 day after radiotherapy, and the inflammatory cell infiltration was marked and almost all viable tumor cells disappeared by day 7 after radiotherapy. Conclusions DWI is a new promising technique for monitoring radiotherapy outcomes. ADC value may give a prior clue on physiological changes of radiotherapy before routine MRI could tell.
基金supported in part by the National Natural Science Foundation of China(61301228,61371091)the Fundamental Research Funds for the Central Universities(3132014212)
文摘This paper is mainly to deal with the problem of direction of arrival(DOA) estimations of multiple narrow-band sources impinging on a uniform linear array under impulsive noise environments. By modeling the impulsive noise as α-stable distribution, new methods which combine the sparse signal representation technique and fractional lower order statistics theory are proposed. In the new algorithms, the fractional lower order statistics vectors of the array output signal are sparsely represented on an overcomplete basis and the DOAs can be effectively estimated by searching the sparsest coefficients. To enhance the robustness performance of the proposed algorithms,the improved algorithms are advanced by eliminating the fractional lower order statistics of the noise from the fractional lower order statistics vector of the array output through a linear transformation. Simulation results have shown the effectiveness of the proposed methods for a wide range of highly impulsive environments.
文摘Objective To evaluate the values of whole body diffusion weighted imaging （DWI） in screenmg pnmary unknown tumor in patients with metastases. Methods Totally, 34 patients with metastases of primary unknown tumors were scanned with whole body DWI, and conventional magnetic resonance （MR） imaging was performed if suspected lesions were detected. All the metastases including 27 cases of osseous metastases, 2 brain metastases, 2 liver metastases, 1 pulmonary multiple metastasis, 1 neck metastasis and 1 malignant ascites, were diagnosed by computed tomography, single photon emission computed tomography, or MR imaging. For the proven primary tumors diagnosed by biopsy or pathology of surgical specimens, apparent diffusion coefficient （ADC） values of the primary and metastatic lesions were measured respectively. The sensitivity and specificity of this technique for screening primary tumors were cvaluated. Results We found 24 cases with suspected primary lesions, in which 23 lesions were proved to be primary tumors, and 1 was proved to be benign lesion. And no definite primary lesion was found in 10 cases on whole body DWI, but in which 1 case was diagnosed with primary tumor by biopsy later, and the other 9 cases remained unknown within follow-up of over halfa year. The difference was not significant in ADC values between primary and metastatic lesions （P〉0.05）. The sensitivity and specificity of whole body DWI for searching primary tumors was 95.8% and 90.0%, respectively. Conclusion Combined with conventional MR scanning, whole body DWI can help to search primary lesions of patients with metastases.
文摘Objective To evaluate the value of whole-body diffusion weighted imaging （WB-DWI） on detection of malignant metastasis. Methods Forty-six patients with malignant tumors underwent WB-DWI examinations between April 2007 and August 2007 in our hospital. Before WB-DWI examination, the primary cancers of all the patients were confirmed by pathology, and the TNM-stage was assessed with conventional magnetic resonance imaging （MRI） or computed tomography （CT）. WB-DWI was performed using short TI inversion recovery echo-planar imaging （STIR-EPI） sequence. Abnormal high signal intensities on WB-DWI were considered as metastases. The results of WB-DWI were compared with other imaging modalities. For the assessment of the diagnostic capability of WB-DWI, WB-DWI were compared with CT for demonstrating mediastinal lymph node metastases and lung metastases, and with conventional MRI for demonstrating metastases in other locations. Results WB-DWI demonstrated 143 focuses, 14 routine imaging. The number of bone metastases depicted of which were diagnosed to be benign lesions in on WB-DWI and routine imaging was 85 and 86; lymph node metastases was 17 and 18; liver metastases was 14 and 14; lung metastases was 4 and 8; and brain metastases was 6 and 8, respectively. WB-DWI failed to detect 12 metastatic lesions including 3 osteoplastic bone metastases, 4 lung metastases, 3 mediastinal lymph node metastases, and 2 brain metastases Four metastatic lesions including 2 deltopectoral lymph nodes and 2 rib metastases were detected with WB-DWI alone, all of which evolved greatly during clinical follow-up for more than 6 months. WB-DWI had higher detection rates for metastatic lesions in liver, bone, and lymph nodes than those in lung and brain （ X^2=30, P〈0.001）. Conclusions WB-DWI could detect most of metastatic lesions that were diagnosed with conventional MRI and CT. The limitations of WB-DWI might be had high false-positive rate and low efficiency in detecting mecliastinal lymph node, brain, and lung metastases.
基金Supported by the National Key Research and Development Program of China(Grant Nos.2017YFA0303603 and 2016YFA0300300)the National Natural Science Foundation of China(Grant Nos.11574383,11774408,and 11574370)+4 种基金the Frontier Program of the Chinese Academy of Sciences(Grant No.QYZDY-SSW-SLH001)the Strategic Priority Research Program of CAS(Grant No.XDB30000000)the Beijing Natural Science Foundation(Grant No.4191003)the International Partnership Program of Chinese Academy of Sciences(Grant No.GJHZ1826)CAS Interdisciplinary Innovation Team。
文摘Distinctive superconducting behaviors between bulk and monolayer FeSe make it challenging to obtain a unified picture of all FeSe-based superconductors.We investigate the ultrafast quasiparticle(QP)dynamics of an intercalated superconductor(Li1-xFex)OHFe1-ySe,which is a bulk crystal but shares a similar electronic structure with single-layer FeSe on SrTiO3.We obtain the electron-phonon coupling(EPC)constant(0.22±0.04),which well bridges that of bulk FeSe crystal and single-layer FeSe on SrTiO3.Significantly,we find that such a positive correlation betweenλA1 g and superconducting Tc holds among all known FeSe-based superconductors,even in line with reported FeAs-based superconductors.Our observation indicates possible universal role of EPC in the superconductivity of all known categories of iron-based superconductors,which is a critical step towards achieving a unified superconducting mechanism for all iron-based superconductors.
