Application of CD34 expression combined with three-phase dynamic contrast-enhanced computed tomography scanning in preoperative staging of gastric cancer

BACKGROUND Accurate preoperative staging of gastric cancer(GC),a common malignant tumor worldwide,is critical for appropriate treatment plans and prognosis.Dynamic three-phase enhanced computed tomography(CT)scanning for preoperative staging of GC has limitations in evaluating tumor angiogenesis.CD34,a marker on vascular endothelial cell surfaces,is promising in evaluating tumor angiogenesis.We explored the value of their combination for preoperative staging of GC to improve the efficacy and prognosis of patients with GC.Medical records of 106 patients with GC treated at the First People's Hospital of Lianyungang between February 2021 and January 2023 were retrospectively studied.All patients underwent three-phase dynamic contrast-enhanced CT scanning before surgery,and CD34 was detected in gastroscopic biopsy specimens.Using surgical and pathological results as the gold standard,the diagnostic results of three-phase dynamic contrast-enhanced CT scanning at different T and N stages were analyzed,and the expression of CD34-marked microvessel density(MVD)at different T and N stages was determined.The specificity and sensitivity of three-phase dynamic contrast-enhanced CT and CD34 in T and N staging were calculated;those of the combined diagnosis of the two were evaluated in parallel.Independent factors affecting lymph node metastasis were analyzed using multiple logistic regression.RESULTS The accuracy of three-phase dynamic contrast-enhanced CT scanning in diagnosing stages T1,T2,T3 and T4 were 68.00%,75.00%,79.41%,and 73.68%,respectively,and for diagnosing stages N0,N1,N2,and N3 were 75.68%,74.07%,85.00%,and 77.27%,respectively.CD34-marked MVD expression increased with increasing T and N stages.Specificity and sensitivity of three-phase dynamic contrast-enhanced CT in T staging were 86.79%and 88.68%;for N staging,89.06%and 92.86%;for CD34 in T staging,64.15%and 88.68%;and for CD34 in N staging,84.38%and 78.57%,respectively.Specificity and sensitivity of joint diagnosis in T staging were 55.68%and 98.72%,and N staging were 75.15%and 98.47%,respectively,with the area under the curve for diagnosis improving accordingly.According to multivariate analysis,a longer tumor diameter,higher pathological T stage,lower differ-entiation degree,and higher expression of CD34-marked MVD were independent risk factors for lymph node metastasis in patients with GC.CONCLUSION With high accuracy in preoperatively determining the invasion depth and lymph node metastasis of GC,CD34 expression and three-phase dynamic contrast-enhanced CT can provide a reliable basis for surgical resection.

Double contrast-enhanced ultrasonography improves diagnostic accuracy of T staging compared with multi-detector computed tomography in gastric cancer patients

BACKGROUND Gastric cancer(GC)is the most common malignant tumor and ranks third for cancer-related deaths among the worldwide.The disease poses a serious public health problem in China,ranking fifth for incidence and third for mortality.Knowledge of the invasive depth of the tumor is vital to treatment decisions.AIM To evaluate the diagnostic performance of double contrast-enhanced ultrasonography(DCEUS)for preoperative T staging in patients with GC by comparing with multi-detector computed tomography(MDCT).METHODS This single prospective study enrolled patients with GC confirmed by preoperative gastroscopy from July 2021 to March 2023.Patients underwent DCEUS,including ultrasonography(US)and intravenous contrast-enhanced ultrasonography(CEUS),and MDCT examinations for the assessment of preoperative T staging.Features of GC were identified on DCEUS and criteria developed to evaluate T staging according to the 8th edition of AJCC cancer staging manual.The diagnostic performance of DCEUS was evaluated by comparing it with that of MDCT and surgical-pathological findings were considered as the gold standard.RESULTS A total of 229 patients with GC(80 T1,33 T2,59 T3 and 57 T4)were included.Overall accuracies were 86.9%for DCEUS and 61.1%for MDCT(P<0.001).DCEUS was superior to MDCT for T1(92.5%vs 70.0%,P<0.001),T2(72.7%vs 51.5%,P=0.041),T3(86.4%vs 45.8%,P<0.001)and T4(87.7%vs 70.2%,P=0.022)staging of GC.CONCLUSION DCEUS improved the diagnostic accuracy of preoperative T staging in patients with GC compared with MDCT,and constitutes a promising imaging modality for preoperative evaluation of GC to aid individualized treatment decision-making.

Contrast-enhanced guided endoscopic ultrasound procedures

Contrast-enhanced endoscopic ultrasound(CH-EUS)can overcome the limi-tations of endoscopic ultrasound-guided acquisition by identifying microvessels inside inhomogeneous tumours and improving the characterization of these tumours.Despite the initial enthusiasm that oriented needle sampling under CH-EUS guidance could provide better diagnostic yield in pancreatic solid lesions,further studies did not confirm the supplementary values in cases of tissue acquisition guided by CH-EUS.This review details the knowledge based on the available data on contrast-guided procedures.The indications for CH-EUS tissue acquisition include isoechoic EUS lesions with poor visible delineation where CH-EUS can differentiate the lesion vascularisation from the surrounding parenchyma and also the mural nodules within biliopancreatic cystic lesions,which occur in select cases.Additionally,the roles of CH-EUS-guided therapy in patients whose pancreatic fluid collections or bile ducts that have an echogenic content have indications for drainage,and patients who have nonvisualized vessels that need to be highlighted via Doppler EUS are presented.Another indication is represented if there is a need for an immediate assessment of the post-radiofrequency ablation of pancreatic neuroendocrine tumours,in which case CH-EUS can be used to reveal the incomplete tumour destruction.

A landslide monitoring method using data from unmanned aerial vehicle and terrestrial laser scanning with insufficient and inaccurate ground control points

Non-contact remote sensing techniques,such as terrestrial laser scanning(TLS)and unmanned aerial vehicle(UAV)photogrammetry,have been globally applied for landslide monitoring in high and steep mountainous areas.These techniques acquire terrain data and enable ground deformation monitoring.However,practical application of these technologies still faces many difficulties due to complex terrain,limited access and dense vegetation.For instance,monitoring high and steep slopes can obstruct the TLS sightline,and the accuracy of the UAV model may be compromised by absence of ground control points(GCPs).This paper proposes a TLS-and UAV-based method for monitoring landslide deformation in high mountain valleys using traditional real-time kinematics(RTK)-based control points(RCPs),low-precision TLS-based control points(TCPs)and assumed control points(ACPs)to achieve high-precision surface deformation analysis under obstructed vision and impassable conditions.The effects of GCP accuracy,GCP quantity and automatic tie point(ATP)quantity on the accuracy of UAV modeling and surface deformation analysis were comprehensively analyzed.The results show that,the proposed method allows for the monitoring accuracy of landslides to exceed the accuracy of the GCPs themselves by adding additional low-accuracy GCPs.The proposed method was implemented for monitoring the Xinhua landslide in Baoxing County,China,and was validated against data from multiple sources.

Survival Analysis of Patients Undergoing Intraoperative Contrast-enhanced Ultrasound in the Surgical Treatment of Malignant Glioma

Objective:Complete resection of malignant gliomas is often challenging.Our previous study indicated that intraoperative contrast-enhanced ultrasound(ICEUS)could aid in the detection of residual tumor remnants and the total removal of brain lesions.This study aimed to investigate the survival rates of patients undergoing resection with or without the use of ICEUS and to assess the impact of ICEUS on the prognosis of patients with malignant glioma.Methods:A total of 64 patients diagnosed with malignant glioma(WHO grade HI and IV)who underwent surgery between 2012 and 2018 were included.Among them,29 patients received ICEUS.The effects of ICEUS on overall survival(OS)and progression-free survival(PFS)of patients were evaluated.A quantitative analysis was performed to compare ICEUS parameters between gliomas and the surrounding tissues.Results:The ICEUS group showed better survival rates both in OS and PFS than the control group.The univariate analysis revealed that age,pathology and ICEUS were significant prognostic factors for PFS,with only age being a significant prognostic factor for OS.In multivariate analysis,age and ICEUS were significant prognostic factors for both OS and PFS.The quantitative analysis showed that the intensity and transit time of microbubbles reaching the tumors were significantly different from those of microbubbles reaching the surrounding tissue.Conclusion:ICEUS facilitates the identification of residual tumors.Age and ICEUS are prognostic factors for malignant glioma surgery,and use of ICEUS offers a better prognosis for patients with malignant glioma.

Acousto-optic scanning multi-photon lithography with high printing rate

As a manufacturing method that is focused on end-users,3D printing has gained a lot of attention in recent years due to its unique advantages in fabricating complex three-dimensional structures.Various new micro-nano 3D printing methods have been developed to meet the demand for high-precision and high-yield manufacturing1-9.Among them,multi-photon-photon lithography(MPL) is a promising 3D nanofabrication technology due to its capability of true 3D digital processing and nanoscale processing resolution beyond the diffraction limit.It has been widely used to fabricate microoptics10,11,photonic crystals12,microfluidics13,meta-surfaces14,and mechanical metamaterials15.

Ultrasound Scanning Competencies in Midwifery Education in Zambia: Findings from a Desk Review and Needs Assessment

Introduction: Ultrasound is an essential component of antenatal care. Midwives provide most of the antenatal care but they do not perform ultrasound as it has been beyond their scope of practice. This leaves many women in Low and Middle-Income Countries without access to ultrasound scanning. The aim of this study was to identify competencies in ultrasound scanning in midwifery education. Methods: A desk review and needs assessment were conducted between July and October 2023. Articles and curricula on the internet, Google scholar and PubMed were searched for content on ultrasound scanning competencies. A Google form consisting of 20 questions was administered via email and WhatsApp to 135 participants. Descriptive statistics were used to analyse data. Results: The desk review showed that it is feasible to train midwives in ultrasound scanning. The training programs for midwives in obstetric ultrasound were conducted for 1 week to 3 months with most of them running for 4 weeks. Content included introduction to general principles of ultrasound, physics, basic knowledge in embryology, obstetrics, anatomy, measuring foetal biometry, estimating amniotic fluid and gestational age. Experts like sonographers trained midwives. Theory and hands on were the teaching methods used. Written and practical assessments were conducted. Needs assessment revealed that majority of participants 71 (53%) knew about basic ultrasound training for midwives. All participants (100%) said it is necessary to train midwives in basic ultrasound scan in Zambia. Some content should include, anatomy, measuring foetal biometry, assessing amniotic fluid level, and gestational age determination. Most participants 91 (67%) suggested that the appropriate duration of training is 4 - 6 weeks. Conclusion: Empowering every midwife with ultrasound scanning skills will enable early detection of any abnormality among pregnant women and prompt intervention to save lives.

Evaluating microvascular invasion in hepatitis B virus-related hepatocellular carcinoma based on contrast-enhanced computed tomography radiomics and clinicoradiological factors

BACKGROUND Microvascular invasion(MVI)is a significant indicator of the aggressive behavior of hepatocellular carcinoma(HCC).Expanding the surgical resection margin and performing anatomical liver resection may improve outcomes in patients with MVI.However,no reliable preoperative method currently exists to predict MVI status or to identify patients at high-risk group(M2).AIM To develop and validate models based on contrast-enhanced computed tomo-graphy(CECT)radiomics and clinicoradiological factors to predict MVI and identify M2 among patients with hepatitis B virus-related HCC(HBV-HCC).The ultimate goal of the study was to guide surgical decision-making.METHODS A total of 270 patients who underwent surgical resection were retrospectively analyzed.The cohort was divided into a training dataset(189 patients)and a validation dataset(81)with a 7:3 ratio.Radiomics features were selected using intra-class correlation coefficient analysis,Pearson or Spearman’s correlation analysis,and the least absolute shrinkage and selection operator algorithm,leading to the construction of radscores from CECT images.Univariate and multivariate analyses identified significant clinicoradiological factors and radscores associated with MVI and M2,which were subsequently incorporated into predictive models.The models’performance was evaluated using calibration,discrimination,and clinical utility analysis.RESULTS Independent risk factors for MVI included non-smooth tumor margins,absence of a peritumoral hypointensity ring,and a high radscore based on delayed-phase CECT images.The MVI prediction model incorporating these factors achieved an area under the curve(AUC)of 0.841 in the training dataset and 0.768 in the validation dataset.The M2 prediction model,which integrated the radscore from the 5 mm peritumoral area in the CECT arterial phase,α-fetoprotein level,enhancing capsule,and aspartate aminotransferase level achieved an AUC of 0.865 in the training dataset and 0.798 in the validation dataset.Calibration and decision curve analyses confirmed the models’good fit and clinical utility.CONCLUSION Multivariable models were constructed by combining clinicoradiological risk factors and radscores to preoper-atively predict MVI and identify M2 among patients with HBV-HCC.Further studies are needed to evaluate the practical application of these models in clinical settings.

Gastrointestinal contrast-enhanced ultrasonography for diagnosis and treatment of peptic ulcer in children

BACKGROUND The detection rate of peptic ulcer in children is improving,with development of diagnostic procedures.Gastroscopy is the gold standard for the diagnosis of peptic ulcer,but it is an invasive procedure.Gastrointestinal contrast-enhanced ultrasonography(CEUS)has the advantages of being painless,noninvasive,nonradioactive,easy to use,and safe.AIM To investigate the clinical value of CEUS for diagnosis and treatment of peptic ulcer in children.METHODS We investigated 43 children with digestive tract symptoms in our hospital from January 2021 to June 2022.All children were examined by routine ultrasound,gastrointestinal CEUS,and gastroscopy.The pathological results of gastroscopy were taken as the gold standard.Routine ultrasonography was performed before gastrointestinal CEUS.Conventional ultrasound showed the thickness of the gastroduodenal wall,gastric peristalsis,and the adjacent organs and tissues around the abdominal cavity.Gastrointestinal CEUS recorded the thickness of the gastroduodenal wall;the size,location and shape of the ulcer;gastric peristalsis;and adjacent organs and tissues around the abdominal cavity.The results of routine ultrasound and gastrointestinal ultrasound were compared with those of gastroscopy to evaluate the diagnostic results and coincidence rate of routine ultrasound and gastrointestinal CEUS.All children received informed consent from their guardians for CEUS.This study was reviewed and approved by the hospital medical ethics committee.RESULTS Among the 43 children,17(15 male,2 female)were diagnosed with peptic ulcer by gastroscopy.There were 26 children with nonpeptic ulcer.There were eight cases of peptic ulcer and 35 of nonpeptic ulcer diagnosed by conventional ultrasound.The diagnostic coincidence rate of peptic ulcer in children diagnosed by conventional ultrasound was 79.1%(34/43),which was significantly different from that of gastroscopy(P=0.033).It indicates that the coincidence rate of gastrointestinal contrast-enhanced ultrasound and gastroscope is low.Fifteen cases of peptic ulcer and 28 of nonpeptic ulcer were diagnosed by CEUS.The diagnostic coincidence rate of peptic ulcer in children was 95.3%(41/43).There was no significant difference between CEUS and gastroscopy(P=0.655).It indicates that the coincidence rate of gastrointestinal contrast-enhanced ultrasound and gastroscope is high.CONCLUSION Gastrointestinal CEUS has a high coincidence rate in the diagnosis of peptic ulcer in children,and can be used as a preliminary examination method.

Investigation of reflection anisotropy induced by micropipe defects on the surface of a 4H-SiC single crystal using scanning anisotropy microscopy

Optical reflection anisotropy microscopy mappings of micropipe defects on the surface of a 4H-SiC single crystal are studied by the scanning anisotropy microscopy(SAM)system.The reflection anisotropy(RA)image with a'butterfly pattern'is obtained around the micropipes by SAM.The RA image of the edge dislocations is theoretically simulated based on dislocation theory and the photoelastic principle.By comparing with the Raman spectrum,it is verified that the micropipes consist of edge dislocations.The different patterns of the RA images are due to the different orientations of the Burgers vectors.Besides,the strain distribution of the micropipes is also deduced.One can identify the dislocation type,the direction of the Burgers vector and the optical anisotropy from the RA image by using SAM.Therefore,SAM is an ideal tool to measure the optical anisotropy induced by the strain field around a defect.

Prophylactic Pattern Scanning Laser Retinal Photocoagulation for Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats: Preliminary Experimental Results

Research Background and Purpose: The number of diabetic patients is rapidly increasing, making it crucial to find methods to prevent diabetic retinopathy (DR), a leading cause of blindness. We investigated the effects of prophylactic pattern scanning laser retinal photocoagulation on DR development in Spontaneously Diabetic Torii (SDT) fatty rats as a new prevention approach. Methods: Photocoagulation was applied to the right eyes of 8-week-old Spontaneously Diabetic Torii (SDT) fatty rats, with the left eyes serving as untreated controls. Electroretinography at 9 and 39 weeks of age and pathological examinations, including immunohistochemistry for vascular endothelial growth factor and glial fibrillary acidic protein at 24 and 40 weeks of age, were performed on both eyes. Results: There were no significant differences in amplitude and prolongation of the OP waves between the right and left eyes in SDT fatty rats at 39 weeks of age. Similarly, no significant differences in pathology and immunohistochemistry were observed between the right and left eyes in SDT fatty rats at 24 and 40 weeks of age. Conclusion: Prophylactic pattern scanning retinal laser photocoagulation did not affect the development of diabetic retinopathy in SDT fatty rats.

Correlation of dynamic contrast-enhanced ultrasonography and the Ki-67 labelling index in pancreatic ductal adenocarcinoma

BACKGROUND Pancreatic ductal adenocarcinoma(PDAC)is a highly malignant and aggressive tumor,and high Ki-67 expression indicates poor histological differentiation and prognosis.Therefore,one of the challenges in diagnosing preoperatively patients with PDAC is predicting the degree of malignancy.Dynamic contrast-enhanced ultrasonography(DCE-US)plays a crucial role in abdominal tumor diagnosis,and can adequately show the microvascular composition within the tumors.However,the relationship between DCE-US and the Ki-67 labelling index remains unclear at the present time.AIM To predict the correlation between Ki-67 expression and the parameters of DCEUS.METHODS Patients with PDAC who underwent DCE-US were retrospectively analyzed.Patients who had received any treatment(radiotherapy or chemotherapy)prior to DCE-US;had incomplete clinical,imaging,or pathologic information;and had poor-quality image analysis were excluded.Correlations between Ki-67 expression and the parameters of DCE-US in patients with PDAC were assessed using Spearman’s rank correlation analysis.The diagnostic performances of these parameters in high Ki-67 expression group were evaluated according to receiver operating characteristic curve.RESULTS Based on the Ki-67 labelling index,30 patients were divided into two groups,i.e.,the high expression group and the low expression group.Among the relative quantitative parameters between the two groups,relative half-decrease time(rHDT),relative peak enhancement,relative wash-in perfusion index and relative wash-in rate were significantly different between two groups(P=0.018,P=0.025,P=0.028,P=0.035,respectively).The DCE-US parameter rHDT was moderately correlated with Ki-67 expression,and rHDT≥1.07 was more helpful in accurately diagnosing high Ki-67 expression,exhibiting a sensitivity and specificity of 53.8%and 94.1%,respectively.CONCLUSION One parameter of DCE-US,rHDT,correlates with high Ki-67 expression.It demonstrates that parameters obtained noninvasively by DCE-US could better predict Ki-67 expression in PDAC preoperatively.

Clinical value of oral contrast-enhanced ultrasonography in diagnosis of gastric tumors

BACKGROUND The incidence of gastric cancer remains high,and it is the sixth most common cancer and the fourth leading cause of cancer deaths worldwide.Oral contrastenhanced ultrasonography is a simple,non-invasive,and painless method for the diagnosis of gastric tumors.AIM To explore the diagnostic value of oral contrast-enhanced ultrasonography for the detection of gastric tumors.METHODS The screening results based on oral contrast-enhanced ultrasonography and electronic gastroscopy were compared with those of the postoperative pathological examination.RESULTS Among 42 patients with gastric tumors enrolled in the study,the diagnostic accordance rate was 95.2%for oral contrast-enhanced ultrasonography(n=40)and 90.5%for electronic gastroscopy(n=38)compared with postoperative pathological examination.The Kappa value of consistency test with pathological findings was 0.812 for oral contrast-enhanced ultrasonography and 0.718 for electronic gastroscopy,and there was no significant difference between them(P=0.397).For the TNM staging of gastric tumors,the accuracy rate of oral contrast enhanced ultrasonography was 81.9%for the overall T staging and 50%,77.8%,100%,and 100%for T1,T2,T3,and T4 staging,respectively.The sensitivity and specificity were both 100%for stages T3 and T4.The diagnostic accuracy rate of oral contrast-enhanced ultrasonography was 93.8%,80%,100%,and 100%for stages N0,N1-N3,M0,and M1,respectively.CONCLUSION The accordance rate of qualitative diagnosis by oral contrast-enhanced ultrasonography is comparable to that of gastroscopy,and it could be used as the preferred method for the early screening of gastric tumors.

Accuracy of tree mapping based on hand-held laser scanning comparing leaf-on and leaf-off conditions in mixed forests

The use of mobile laser scanning to survey forest ecosystems is a promising,scalable technology to describe forest 3D structures at high resolution.To confirm the con-sistency in the retrieval of forest structural parameters using hand-held laser scanning(HLS),before operationalizing the method,confirming the data is crucial.We analyzed the per-formance of tree-level mapping based on HLS under differ-ent phenology conditions on a mixed forest in western Spain comprising Pinus pinaster and two deciduous species,Alnus glutinosa and Quercus pyrenaica.The area was surveyed twice during the growing season(July 2022)and once in the deciduous season(February 2022)using several scan-ning paths.Ground reference data(418 trees,15 snags)was used to calibrate the HLS data and to assess the influence of phenology when converting 3D data into tree-level attrib-utes(DBH,height and volume).The HLS-based workflow was robust at isolating tree positions and recognizing stems despite changes in phenology.Ninety-six percent of all pairs matched below 65 cm.For DBH,phenology barely altered estimates.We observed a strong agreement when comparing HLS-based tree height distributions.The values exceeded 2 m when comparing height measurements,confirming height data should be carefully used as reference in remote sensing-based inventories,especially for deciduous species.Tree volume was more precise for pines(r=0.95,and rela-tive RMSE=21.3–23.8%)compared to deciduous species(r=0.91–0.96,and relative RMSE=27.3–30.5%).HLS data and the forest structural complexity tool performed remark-ably,especially in tree positioning considering mixed forests and mixed phenology conditions.

A review of understanding electrocatalytic reactions in energy conversion and energy storage systems via scanning electrochemical microscopy

To address climate change and promote environmental sustainability,electrochemical energy conversion and storage systems emerge as promising alternative to fossil fuels,catering to the escalating demand for energy.Achieving optimal energy efficiency and cost competitiveness in these systems requires the strategic design of electrocatalysts,coupled with a thorough comprehension of the underlying mechanisms and degradation behavior occurring during the electrocatalysis processes.Scanning electrochemical microscopy(SECM),an analytical technique for studying surface electrochemically,stands out as a powerful tool offering electrochemical insights.It possesses remarkable spatiotemporal resolution,enabling the visualization of the localized electrochemical activity and surface topography.This review compiles crucial research findings and recent breakthroughs in electrocatalytic processes utilizing the SECM methodology,specifically focusing on applications in electrolysis,fuel cells,and metal–oxygen batteries within the realm of energy conversion and storage systems.Commencing with an overview of each energy system,the review introduces the fundamental principles of SECM,and aiming to provide new perspectives and broadening the scope of applied research by describing the major research categories within SECM.

Imaging of human parafoveal area with large field of view in adaptive optics line scanning ophthalmoscope

The parafoveal area,with its high concentration of photoreceptors andfine retinal capillaries,is crucial for central vision and often exhibits early signs of pathological changes.The current adaptive optics scanning laser ophthalmoscope(AOSLO)provides an excellent tool to acquire accurate and detailed information about the parafoveal area with cellular resolution.However,limited by the scanning speed of two-dimensional scanning,thefield of view(FOV)in the AOSLO system was usually less than or equal to 2,and the stitching for the parafoveal area required dozens of images,which was time-consuming and laborious.Unfortunately,almost half of patients are unable to obtain stitched images because of their poorfixation.To solve this problem,we integrate AO technology with the line-scan imaging method to build an adaptive optics line scanning ophthalmoscope(AOLSO)system with a larger FOV.In the AOLSO,afocal spherical mirrors in pairs are nonplanar arranged and the distance and angle between optical elements are optimized to minimize the aberrations,two cylinder lenses are orthogonally placed before the imaging sensor to stretch the point spread function(PSF)for sufficiently digitizing light energy.Captured human retinal images show the whole parafoveal area with 55FOV,60 Hz frame rate and cellular resolutions.Take advantage of the 5FOV of the AOLSO,only 9 frames of the retina are captured with several minutes to stitch a montage image with an FOV of 99,in which photoreceptor counting is performed within approximately 5eccentricity.The AOLSO system not only provides cellular resolution but also has the capability to capture the parafoveal region in a single frame,which offers great potential for noninvasive studying of the parafoveal area.

Influence of pore structure heterogeneity on channeling channels during hot water flooding in heavy oil reservoir based on CT scanning

Hot water flooding is an effective way to develop heavy oil reservoirs.However,local channeling channels may form,possibly leading to a low thermal utilization efficiency and high water cut in the reservoir.The pore structure heterogeneity is an important factor in forming these channels.This study proposes a method that mixes quartz sand with different particle sizes to prepare weakly heterogeneous and strongly heterogeneous models through which hot water flooding experiments are conducted.During the experiments,computer tomography(CT)scanning identifies the pore structure and micro remaining oil saturation distribution to analyze the influence of the pore structure heterogeneity on the channeling channels.The oil saturation reduction and average pore size are divided into three levels to quantitatively describe the relationship between the channeling channel distribution and pore structure heterogeneity.The zone where oil saturation reduction exceeds 20%is defined as a channeling channel.The scanning area is divided into 180 equally sized zones based on the CT scanning images,and threedimensional(3D)distributions of the channeling channels are developed.Four micro remaining oil distribution patterns are proposed,and the morphology characteristics of micro remaining oil inside and outside the channeling channels are analyzed.The results show that hot water flooding is more balanced in the weakly heterogeneous model,and the oil saturation decreases by more than 20%in most zones without narrow channeling channels forming.In the strongly heterogeneous model,hot water flooding is unbalanced,and three narrow channeling channels of different lengths form.In the weakly heterogeneous model,the oil saturation reduction is greater in zones with larger pores.The distribution range of the average pore size is larger in the strongly heterogeneous model.The network remaining oil inside the channeling channels is less than outside the channeling channels,and the hot water converts the network remaining oil into cluster,film,and droplet remaining oil.

Clinical application of oral contrast-enhanced ultrasound in evaluating the preoperative T staging of gastric cancer

BACKGROUND Oral contrast-enhanced ultrasound(OCEUS)is widely used in the noninvasive diagnosis and screening of gastric cancer(GC)in China.AIM To investigate the clinical application of OCEUS in evaluating the preoperative T staging of gastric cancer.METHODS OCEUS was performed before the operation,and standard ultrasound images were retained.The depth of infiltration of GC(T-stage)was evaluated according to the American Joint Committee on Cancer 8th edition of the tumor-nodemetastasis staging criteria.Finally,with postoperative pathological staging as the gold standard reference,the sensitivity,specificity,negative predictive value,positive predictive value,and diagnostic value of OCEUS T staging were evaluated.RESULTS OCEUS achieved diagnostic accuracy rates of 76.6%(T1a),69.6%(T1b),62.7%(T2),60.8%(T3),88.0%(T4a),and 88.7%(T4b),with an average of 75.5%.Ultrasonic T staging sensitivity exceeded 62%,aside from T1b at 40.3%,while specificity was over 91%,except for T3 with 83.5%.The Youden index was above 60%,with T1b and T2 being exceptions.OCEUS T staging corresponded closely with pathology in T4b(kappa>0.75)and moderately in T1a,T1b,T2,T3,and T4a(kappa 0.40-0.75),registering a concordance rate exceeding 84%.CONCLUSION OCEUS was effective,reliable,and accurate in diagnosing the preoperative T staging of GC.As a noninvasive diagnostic technique,OCEUS merits clinical popularization.

Assessing the dynamics of O_(2) desorption from cobalt phthalocyanine by in situ electrochemical scanning tunneling microscopy

We report here the in situ electrochemical scanning tunneling microscopy(ECSTM) study of cobalt phthalocyanine(CoPc)-catalyzed O_(2) evolution reaction(OER) and the dynamics of CoPc-O_(2) dissociation.The self-assembled CoPc monolayer is fabricated on Au(111) substrate and resolved by ECSTM in 0.1 M KOH electrolyte.The OH^(-)adsorption on CoPc prior to OER is observed in ECSTM images.During OER,the generated O_(2) adsorbed on Co Pc is observed in the CoPc monolayer.Potential step experiment is employed to monitor the desorption of OER-generated O_(2) from CoPc,which results in the decreasing surface coverage of CoPc-O_(2) with time.The rate constant of O_(2) desorption is evaluated through data fitting.The insights into the dynamics of Co-O_(2) dissociation at the molecular level via in situ imaging help understand the role of Co-O_(2) in oxygen reduction reaction(ORR) and OER.

Fatigue properties and damage constitutive model of salt rock based on CT scanning

To investigate the macroscopic fatigue properties and the mesoscopic pore evolution characteristics of salt rock under cyclic loading,fatigue tests under different upper-limit stresses were carried out on salt rock,and the mesoscopic pore structures of salt rock before and after fatigue tests and under different cycle numbers were measured using CT scanning instrument.Based on the test results,the effects of the cycle number and the upper-limit stress on the evolution of cracks,pore morphology,pore number,pore volume,pore size,plane porosity,and volume porosity of salt rock were analyzed.The failure path of salt rock specimens under cyclic loading was analyzed using the distribution law of plane porosity.The damage variable of salt rock under cyclic loading was defined on basis of the variation of volume porosity with cycle number.In order to describe the fatigue deformation behavior of salt rock under cyclic loading,the nonlinear Burgers damage constitutive model was further established.The results show that the model established can better reflect the whole development process of fatigue deformation of salt rock under cyclic loading.