类器官模型在结直肠癌研究中的应用

类器官是近年来逐渐兴起的一种新型研究模型,在疾病发展、药物筛选、新药研发、个性化医疗等领域应用前景广阔。近年来,结直肠癌类器官模型已较为成熟,本文对结直肠癌研究中的常见模型及其类器官模型的构建与应用现状作一综述。

Mechanical characteristic and failure mechanism of joint with composite sucker rod

Composite sucker rods are widely used in oil fields because of light weight,high strength,and corrosion resistance.Bonded technology becomes the primary connection method of composites.However,the joints with composite sucker rods are prone to debone and fracture.The connected characteristics are less considered,so the failure mechanism of the joint is still unclear.Based on the cohesive zone model(CZM)and the Johnson-Cook constitutive model,a novel full-scale numerical model of the joint with composite sucker rod was established,and verified by pull-out experiments.The mechanical properties and slip characteristics of the joint were studied,and the damaged procession of the joint was explored.The results showed that:a)the numerical model was in good agreement with the experimental results,and the error is within 5%;b)the von Mises stress,shear stress,and interface stress distributed symmetrically along the circumferential path increased gradually from the fixed end to the loading end;c)the first-bonded interface near the loading end was damaged at first,followed by debonding of the second-bonded interface,leading to the complete shear fracture of the epoxy,and resulted in the debonding of the joint with composite sucker rod,which can provide a theoretical basis for the structural design and optimization of the joint.

Four-stage cascaded variable optical attenuator with large attenuation range for quantum key distribution

A four-stage cascaded variable optical attenuator(VOA)with a large attenuation range is presented.The VOA is based on a Mach–Zehnder interferometer(MZI)and fabricated in a silica-based planar lightwave circuit(PLC)platform.The thermo-optic effect is used to achieve intensity modulation.The measured maximum attenuation of the four-stage cascaded VOA is 88.38 d B.The chip is also tested in a quantum key distribution(QKD)system to generate signal and decoy states.The mean photon number after attenuation of the four-stage cascaded VOA is less than 0.1,which can meet the requirement of QKD.

应激在肠易激综合征致病机制中的作用

肠易激综合征(irritable bowel syndrome,IBS)是世界上最常见的功能性胃肠道紊乱疾病之一,以慢性间歇性腹痛,结肠动力障碍及排便习惯改变为特点,影响着大量患者的生活.内脏敏感性和消化道通透性增高是IBS中的重要病理生理机制但IBS确切的致病机制仍不清楚,目前认为涉及多种因素.精神心理因素尤其是应激在IBS的发生、发展和调节中占重要地位.本文综述了应激与IBS动物模型的关系以及应激在IBS内脏高敏、消化道高通透性机制中的作用,以期为进一步研究IBS的发病机制提供参考.

In vivo evaluation of early renal damage in type 2 diabetic patients on 3.0 T MR diffusion tensor imaging

AIM To investigate the utility of renal diffusion tensor imaging(DTI) to detect early renal damage in patients with type 2 diabetes.METHODS Twenty-six diabetic patients(12 with microalbuminuria(MAU), and 14 with normoalbuminuria) and fourteen healthy volunteers were prospectively included in this study. Renal DTI on 3.0 T MR was performed, and estimated glomerular filtration rate(e GFR) was recorded for each subject. Mean cortical and medullary fractional anisotropy(FA) values were calculated by placing multiple representative regions of interest. Mean FA values were statistically compared among groups. Correlations between FA values and e GFR were evaluated. RESULTS Both cortical and medullary FA were significantly reduced in diabetic patients compared to healthy controls(0.403 ± 0.064 vs 0.463 ± 0.047, P = 0.004, and 0.556 ± 0.084 vs 0.645 ± 0.076, P = 0.002, respectively). Cortical FA was significantly lower in diabetic patients with NAU than healthy controls(0.412 ± 0.068 vs 0.463 ± 0.047, P = 0.02). Medullary FA in diabetic patients with NAU and healthy controls were similar(0.582 ± 0.096 vs 0.645 ± 0.076, P = 0.06). Both cortical FA and medullary FA correlated with e GFR(r = 0.382, P = 0.015 and r = 0.552, P = 0.000, respectively).CONCLUSION FA of renal parenchyma on DTI might serve as a more sensitive biomarker of early diabetic nephropathy than MAU.

CRISPR/Cas9-mediated VvPR4b editing decreases downy mildew resistance in grapevine(Vitis vinifera L.)

Downy mildew of grapevine(Vitis vinifera L.),caused by the oomycete pathogen Plasmopara viticola,is one of the most serious concerns for grape production worldwide.It has been widely reported that the pathogenesis-related 4(PR4)protein plays important roles in plant resistance to diseases.However,little is known about the role of PR4 in the defense of grapevine against P.viticola.In this study,we engineered loss-of-function mutations in the VvPR4b gene from the cultivar“Thompson Seedless”using the CRISPR/Cas9 system and evaluated the consequences for downy mildew resistance.Sequencing results showed that deletions were the main type of mutation introduced and that no off-target events occurred.Infection assays using leaf discs showed that,compared to wild-type plants,the VvPR4b knockout lines had increased susceptibility to P.viticola.This was accompanied by reduced accumulation of reactive oxygen species around stomata.Measurement of the relative genomic abundance of P.viticola in VvPR4b knockout lines also demonstrated that the mutants had increased susceptibility to the pathogen.Our results confirm that VvPR4b plays an active role in the defense of grapevine against downy mildew.

Determination of neutron-skin thickness using configurational information entropy

Configurational information entropy(CIE)theory was employed to determine the neutron-skin thickness of neutron-rich calcium isotopes.The nuclear density distributions and fragment cross sections in 350 MeV/u ^(40-60)Ca+^(9)Be projectile fragmentation reactions were calculated using a modified statistical abrasion-ablation model.CIE quantities were determined from the nuclear density,isotopic,mass,and charge distributions.The linear correlations between the CIE determined using the isotopic,mass,and charge distributions and the neutron-skin thickness of the projectile nucleus show that CIE provides new methods to extract the neutron-skin thickness of neutron-rich nuclei.

Multiple-models predictions for drip line nuclides in projectile fragmentation of^(40,48)Ca,^(58,64)Ni,and^(78,86)Kr at 140 MeV/u

Modern rare isotope beam(RIB)factories will significantly enhance the production of extremely rare isotopes(ERI)at or near drip lines.As one of the most important methods employed in RIB factories,the production of ERIs in projectile fragmentation reactions should be theoretically improved to provide better guidance for experimental research.The cross-sections of ERIs produced in 140 MeV/u^(78,86)Kr/^(58,64)Ni/^(40,48)Ca+9Be projectile fragmentation reactions were predicted using the newly proposed models[i.e.,Bayesian neural network(BNN),BNN+FRACS,and FRACS,see Chin.Phys.C,46:074104(2022)]and the frequently used EPAX3 model.With a minimum cross-section of 1015 mb,the possibilities of ERIs discovery in a new facility for rare isotope beams(FRIB)are discussed.

Measurements of the ^(107)Ag neutron capture cross sections with pulse height weighting technique at the CSNS Back-n facility

Silver indium cadmium(Ag–In–Cd) control rod is widely used in pressurized water reactor nuclear power plants,and it is continuously consumed in a high neutron flux environment. The mass ratio of ^(107)Ag in the Ag–In–Cd control rod is 41.44%. To accurately calculate the consumption value of the control rod, a reliable neutron reaction cross section of the ^(107)Ag is required. Meanwhile,^(107)Ag is also an important weak r nucleus. Thus, the cross sections for neutron induced interactions with ^(107)Ag are very important both in nuclear energy and nuclear astrophysics. The(n, γ) cross section of ^(107)Ag has been measured in the energy range of 1–60 eV using a back streaming white neutron beam line at China spallation neutron source. The resonance parameters are extracted by an R-matrix code. All the cross section of ^(107)Ag and resonance parameters are given in this paper as datasets. The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00010.

Measurements ofthe 197Au(n, γ) crosssectionupto100keV at the CSNSBack-nfacility

The neutron capture cross section of 197 Au was measured using the time-of-flight(TOF)technique at the Back-n facility of the China Spallation Neutron Source(CSNS)in the 1 eV to 100 keV range.Prompt c-rays originating from neutron-induced capture events were detected by four C_(6)D_(6) liquid scintillator detectors.Pulse height weighting technology(PHWT)was used to analyze the data.The results are in good agreement with ENDF/B-VIII.0,CENDL-3.1,and other evaluated libraries in the resonance region,and in agreement with both n TOF and GELINA experimental data in the 5–100 keV range.Finally,the resonance peaks in the energy range from 1eV to 1 keV were fitted by the SAMMY R-matrix code.

Functional assessment of transplanted kidneys with magnetic resonance imaging

Kidney transplantation has emerged as the treatment of choice for many patients with end-stage renal disease, which is a significant cause of morbidity and mortality. Given the shortage of clinically available donor kidneys and the significant incidence of allograft dysfunction, a noninvasive and accurate assessment of the allograft renal function is critical for postoperative management. Prompt diagnosis of graft dysfunction facilitates clinical intervention of kidneys with salvageable function. New advances in magnetic resonance imaging(MRI) technology have enabled the calculation of various renal parameters that were previously not feasible to measure noninvasively. Diffusion-weighted imaging provides information on renal diffusion and perfusion simultaneously, with quantification by the apparent diffusion coefficient, the decrease of which reflects renal function impairment. Diffusion-tensor imaging accounts for the directionality of molecular motion and measures fractional anisotropy of the kidneys. Blood oxygen level-dependent MR evaluates intrarenal oxygen bioavailability, generating the parameter of R2*(reflecting the concentration of deoxyhemoglobin). A decrease in R2* could happen during acute rejection. MR nephro-urography/renography demonstrates structural data depicting urinary tract obstructions and functional data regarding the glomerular filtration and blood flow. MR angiography details the transplant vasculature and is particularly suitable for detecting vascular complications, with good correlation with digital subtraction angiography. Other functional MRI technologies, such as arterial spin labeling and MR spectroscopy, are showing additional promise. This review highlights MRI as a comprehensive modality to diagnose a variety of etiologies of graft dysfunction, including prerenal(e.g., renal vasculature), renal(intrinsic causes) and postrenal(e.g., obstruction of the collecting system) etiologies.

Neurological functional evaluation based on accurate motions in big animals with traumatic brain injury

An accurate and effective neurological evaluation is indispensable in the treatment and rehabilitation of traumatic brain injury. However,most of the existing evaluation methods in basic research and clinical practice are not objective or intuitive for assessing the neurological function of big animals, and are also difficult to use to qualify the extent of damage and recovery. In the present study, we established a big animal model of traumatic brain injury by impacting the cortical motor region of beagles. At 2 weeks after successful modeling, we detected neurological deficiencies in the animal model using a series of techniques, including three-dimensional motion capture, electromyogram and ground reaction force. These novel technologies may play an increasingly important role in the field of traumatic brain injury diagnosis and rehabilitation in the future. The experimental protocol was approved by the Animal Care and Use Committee of Logistics University of People's Armed Police Force(approval No. 2017-0006.2).

New experimental measurement of^(nat)Se(n,γ)cross section between 1 eV to 1 keV at the CSNS Back-n facility

The^(74)Se is one of 35 p-nuclei,and^(82)Se is a r-process only nucleus,and their(n,γ)cross sections are vital input parameters for nuclear astrophysics reaction network calculations.The neutron capture cross section in the resonance range of isotopes and even natural selenium samples has not been measured.Promptγ-rays originating from neutron-induced capture events were detected by four C_(6)D_(6) liquid scintillator detectors at the Back-n facility of China Spallation Neutron Source(CSNS).The pulse height weighting technique(PHWT)was used to analyze the data in the 1 e V to 100 ke V region.The deduced neutron capture cross section was compared with ENDF/B-VIII.0,JEFF-3.2,and JENDL-4.0,and some differences were found.Resonance parameters were extracted by the R-matrix code SAMMY in the 1 e V-1 ke V region.All the cross sections ofnatSe and resonance parameters are given in the datasets.The datasets are openly available at http://www.doi.org/10.11922/sciencedb.j00113.00019.

Implantation-decay method to study the β-delayed charged particle decay

In this paper,the implantation-decay method is introduced to study the β-delayed charged particle decay.A silicon detector array was used for the implantation of the incident beams and for the detection of the emitted particles.An experimental measurement on the β-delayed particle emission from ^(22)Al was used to demonstrate the method.The half-life value,charged particle spectroscopy,γ ray spectrum,and γ particle coincidence for the decay process were obtained and compared with previous experimental results for ^(22)Al.The results show that the implantation-decay method,using a silicon detector array,is a suitable experimental method to study the β-delayed charged particle decay for proton-rich nuclei.

Reconstructing the temporal evolution of the speed of light in a flat FRW Universe

We present a novel method to reconstruct the temporal evolution of the speed of light c(z) in a flat Friedmann-Robertson-Walker(FRW) Universe using astronomical observations. After validating our pipeline with mock datasets, we apply our method to the latest baryon acoustic oscillations(BAO) and supernovae observations, and reconstruct c(z) in the redshift range of z ∈[0, 1.5]. We find no evidence of a varying speed of light, although we see some interesting features of △c(z), the fractional difference between c(z) and c0(the speed of light in the International System of Units), e.g.,△c(z)< 0 and △c(z)> 0 at 0.2≤z≤0.5 and 0.8≤z≤1.3, respectively, although the significance of these features is currently far below statistical importance.

Primary malignant peritoneal mesothelioma mimicking tuberculous peritonitis:A case report

BACKGROUND Malignant peritoneal mesothelioma(MPM)is a rare malignancy arising in mesothelial cells in the peritoneum.It can be mistaken for many other diseases,such as peritoneal carcinomatosis and tuberculous peritonitis(TBP),because its clinical manifestations are often nonspecific.Therefore,the diagnosis of MPM is often challenging and delayed.CASE SUMMARY A 42-year-old man was referred to our hospital with lower abdominal pain for 1 wk and ascites observed under abdominal sonography.His laboratory findings revealed an isolated elevated tumor marker of carcinoma antigen 125(167.4 U/m L;normal,<35 U/m L),and contrast enhanced computed tomography showed peritoneal thickening.Thus,differential diagnoses of TBP,carcinomatosis of an unknown nature,and primary peritoneal malignancy were considered.After both esophagogastroduodenoscopy and colonoscopy produced negative findings,laparoscopic intervention was performed.The histopathological results revealed mesothelioma invasion into soft tissue composed of a papillary,tubular,single-cell arrangement of epithelioid cells.In addition,immunohistochemical staining was positive for mesothelioma markers and negative for adenocarcinoma markers.Based on the above findings,TBP was excluded,and the patient was diagnosed with MPM.CONCLUSION It is important to distinguish MPM from TBP because they have similar symptoms and blood test findings.

Diffusion tensor imaging beyond brains: Applications in abdominal and pelvic organs

Functional magnetic resonance imaging(MRI) provided critical functional information in addition to the anatomicprofiles offered by conventional MRI, and has been enormously used in the initial diagnosis and followed evaluation of various diseases. Diffusion tensor imaging(DTI) is a newly developed and advanced technique that measures the diffusion properties including both diffusion motion and its direction in situ, and has been extensively applied in central nerve system with acknowledged success. Technical advances have enabled DTI in abdominal and pelvic organs. Its application is increasing, yet remains less understood. A systematic overview of clinical application of DTI in abdominal and pelvic organs such as liver, pancreas, kidneys, prostate, uterus, etc., is therefore presented. Exploration of techniques with less artifacts and more normative postprocessing enabled generally satisfactory image quality and repeatability of measurement. DTI appears to be more valuable in the evaluation of diffused diseases of organs with highly directionally arranged structures, such as the assessment of function impairment of native and transplanted kidneys. However, the utility of DTI to diagnose focal lesions, such as liver mass, pancreatic and prostate tumor, remains limited. Besides, diffusion of different layers of the uterus and the fiber structure disruption can be depicted by DTI. Finally, a discussion of future directions of research is given. The underlying heterogeneous pathologic conditions of certain diseases need to be further differentiated, and it is suggested that DTI parameters might potentially depict certain pathologic characterization such as cell density. Nevertheless, DTI should be better integrated into the current multi-modality evaluation in clinical practice.

Non-frozen process of heavy-ion fusion reactions at deep sub-barrier energies

The hindrance in heavy-ion fusion reactions a deep sub-barrier energies is investigated using the double folding model with a hybrid method between the frozen and adiabatic density approximations.In this method,the density distributions of the projectile and the target depend closely on the distance between them.As the distance decreased,the half-density radii of the colliding nucle gradually increased to the half-density radius of the compound nucleus.The total potential based on this non-frozen approximation generates a slightly shallower pocket and becomes more attractive inside the pocket compared to that obtained from the frozen approximation.A damping factor was used to simulate the decline of the coupled channel effects owing to the density rearrangement of the two colliding nuclei.The calculated fusion cross-sections and astrophysical S factors at the deep sub-barrier energies are both in good agreement with the experimental data for the medium-heavyNi+Ni and medium-lightMg+Si mass systems.In addition,it was concluded that the apparent maximum of the S factors most likely appears in fusion systems with strong coupling effects.

Using fluorodeoxy-D-glucose-positron emission tomography to monitor neoadjuvant chemotherapy response in sarcoma:A meta-analysis

AIM: To systematically evaluate the accuracy of 18-fluorodeoxy-D-glucose-positron emission tomography(18-FDG PET) to assess response to neoadjuvant chemotherapy in bone and soft tissue sarcomas.METHODS: Studies published in English language regarding the accuracy of F-18 FDG PET for the indication were retrieved from MEDLINE.The QUADAS tool was utilized for methodological quality appraisal.Relevant data were extracted,and quantitative data synthesis included pooled estimation and subgroup analysis.RESULTS: A total of fifteen studies involving 420 patients with pathologically confirmed sarcoma were collected.Methodological quality was relatively high.The pooled sensitivity and specificity of PET to predict histopathological response were 87%(95%CI: 81%-91%) and 83%(95%CI: 77%-87%),respectively.Ten stud-ies employed a lower standardized uptake value(SUV) after chemotherapies(mostly 2.5) and/or a higher SUV reduction rate(mostly around 50%) as PET criteria of good response.Subgroup analysis showed that PET exhibited a significantly better specificity in osteosarcoma(OS) and Ewing sarcoma(ES) than in soft-tissue sarcoma(STS)(91% vs 75%,P < 0.05),and a higher specificity in pediatric patients than in adults(90% vs 74%,P < 0.01).PET yielded a lower specificity in ifosfamidecontained chemotherapies than in the alternative regimen(70% vs 97%,P < 0.01).CONCLUSION: F-18 FDG PET is promising to predict neoadjuvant therapy response in sarcoma,especially in pediatric patients with OS or ES.Certain chemotherapeutic agents could potentially cause false positives of PET.

Probing dynamics of dark energy with latest observations

We examine the validity of the ACDM model and probe the dynamics of dark energy with the latest astronomical observations. Using the Ore（z） diagnosis, we find that various kinds of observational data are in tension within the ACDM framework. We then allow for dynamics of dark energy and investigate the constraint on dark energy parameters. We find that for two different kinds of parametri- sations of the equation of state parameter w, a combination of current data mildly favours an evolving w, although the significance is not sufficient for it to be supported by Bayesian evidence. A forecast of the DESI survey shows that the dynamics of dark energy could be detected at the 7σ confidence level and would be decisively supported by Bayesian evidence, if the best-fit model of w derived from current data is the true model.