Effects of Health Record Computerization in the Context of the COVID-19 Pandemic in Burundi’ Hospitals: Propensity Score Matching

Introduction: A great number of software are currently used to digitalize the patient records in order to optimize the quality of services offered to patients. The objective of this study was to evaluate the effects of Electronic Health Records use in Burundi’s hospitals, taking into account the COVID-19 pandemic context. Methods: This was a quasi-experimental study based on difference in difference method. Ten district hospitals were included in the study, five of them had the Electronic Health Records and five of which did not yet have the Electronic Health Records. The hospital’s control group were chosen using the propensity score matching method. The period before the project’s implementation was 2014 and the period after were 2019 and 2020. Results: After 5 years of the Electronic Health Record’s implementation, the results showed an increase in outpatient consultation (70%), deliveries (more than 100%), caesarean sections (56%) and major surgeries (43%) indicators. The overall quality score of hospitals’ care had a regressive effect of 37% and the income from performance-based funding had an increase by 31%. The indicators which were affected by the context of the COVID-19 pandemic were especially outpatient consultation, caesarian section, income from performance-based funding decreased by 3%, 5% and 20% respectively. Conclusion: The effects of Electronic Health Records use are effective. As the COVID-19 pandemic impacted the hospital’s indicators negatively, the resilient strategies alongside the potential shocks are recommended.

Accurate quantification of the algebraic,multiplicative algebraic,and simultaneous iterative reconstruction techniques in ionosphere rebuilding based on the TIEGCM assessment

The algebraic reconstruction technique(ART),multiplicative algebraic reconstruction technique(MART),and simultaneous iterative reconstruction technique(SIRT)are computational methodologies extensively utilized within the field of computerized ionospheric tomography(CIT)to facilitate three-dimensional reconstruction of the ionospheric morphology.However,reconstruction accuracy elicits recurrent disputes over its practical application,and people usually attribute this issue to incomplete and uneven coverage of the measurements.The Thermosphere Ionosphere Electrodynamics General Circulation Model(TIEGCM)offers a reasonable physics-based ionospheric background and is widely utilized in ionospheric research.We use the TIEGCM simulations as the targeted ionosphere because the current measurements are far from able to realistically reproduce the ionosphere in detail.Optimized designations of satellite measurements are conducted to investigate the limiting performance of CIT methods in ionospheric reconstruction.Similar to common practice,electron density distributions from outputs of the International Reference Ionosphere(IRI)model are used as the iterative initial value in CIT applications.The outcomes suggest that despite data coverage,iterative initial conditions also play an essential role in ionospheric reconstruction.In particular,in the longitudinal sectors where the iterative initial height of the F2-layer peak electron density(hmF2)differs substantially from the background densities,none of the three CIT methods can reproduce the exact background profile.When hmF2 is close but the ionospheric F2-layer peak density(NmF2)is different between the targeted background and initial conditions,the MART performs better than the ART and SIRT,as evidenced by the correlation coefficients of MART being above 0.97 and those of ART and SIRT being below 0.85.In summary,this investigation reveals the potential uncertainties in traditional CIT reconstruction,particularly when realistic hmF2 or NmF2 values differ substantially from the initial CIT conditions.

Computerized tomography-guided therapeutic percutaneous puncture catheter drainage-combined with somatostatin for severe acute pancreatitis: An analysis of efficacy and safety

BACKGROUND Severe acute pancreatitis(SAP),a condition with rapid onset,critical condition and unsatisfactory prognosis,poses a certain threat to human health,warranting optimization of relevant treatment plans to improve treatment efficacy.AIM To evaluate the efficacy and safety of computerized tomography-guided the-rapeutic percutaneous puncture catheter drainage(CT-TPPCD)combined with somatostatin(SS)in the treatment of SAP.METHODS Forty-two SAP patients admitted to The Second Affiliated Hospital of Fujian Medical University from June 2020 to June 2023 were selected.On the basis of routine treatment,20 patients received SS therapy(control group)and 22 patients were given CT-TPPCD plus SS intervention(research group).The efficacy,safety(pancreatic fistula,intra-abdominal hemorrhage,sepsis,and organ dysfunction syndrome),abdominal bloating and pain relief time,bowel recovery time,hospital stay,inflammatory indicators(C-reactive protein,interleukin-6,and pro-calcitonin),and Acute Physiology and Chronic Health Evaluation(APACHE)II score of both groups were evaluated for comparison.RESULTS Compared with the control group,the research group had a markedly higher total effective rate,faster abdominal bloating and pain relief and bowel recovery,INTRODUCTION Pancreatitis,an inflammatory disease occurring in the pancreatic tissue,is classified as either acute or chronic and is associated with high morbidity and mortality,imposing a socioeconomic burden[1,2].The pathogenesis of this disease involves early protease activation,activation of nuclear factor kappa-B-related inflammatory reactions,and infiltration of immune cells[3].Severe acute pancreatitis(SAP)is a serious condition involving systemic injury and subsequent possible organ failure,accounting for 20%of all acute pancreatitis cases[4].SAP is also characterized by rapid onset,critical illness and unsatisfactory prognosis and is correlated with serious adverse events such as systemic inflammatory response syn-drome and acute lung injury,threatening the health of patients[5,6].Therefore,timely and effective therapeutic inter-ventions are of great significance for improving patient prognosis and ensuring therapeutic effects.Somatostatin(SS),a peptide hormone that can be secreted by endocrine cells and the central nervous system,is in-volved in the regulatory mechanism of glucagon and insulin synthesis in the pancreas[7].It has complex and pleiotropic effects on the gastrointestinal tract,which can inhibit the release of gastrointestinal hormones and negatively modulate the exocrine function of the stomach,pancreas and bile,while exerting a certain influence on the absorption of the di-gestive system[8,9].SS has shown certain clinical effectiveness when applied to SAP patients and can regulate the severity of SAP and immune inflammatory responses,and this regulation is related to its influence on leukocyte apoptosis and adhesion[10,11].Computerized tomography-guided therapeutic percutaneous puncture catheter drainage(CT-TPPCD)is a surgical procedure to collect lesion fluid and pus samples from necrotic lesions and perform puncture and drainage by means of CT image examination and precise positioning[12].In the research of Liu et al[13],CT-TPPCD applied to pa-tients undergoing pancreatic surgery contributes to not only good curative effects but also a low surgical risk.Baudin et al[14]also reported that CT-TPPCD has a clinical success rate of 64.6%in patients with acute infectious necrotizing pan-creatitis,with nonfatal surgery-related complications found in only two cases,suggesting that this procedure is clinically effective and safe in the treatment of the disease.In light of the limited studies on the efficacy and safety of SS plus CT-TPPCD in SAP treatment,this study performed a relevant analysis to improve clinical outcomes in SAP patients.

Pancreatic volume change using three dimensional-computed tomography volumetry and its relationships with diabetes on longterm follow-up in autoimmune pancreatitis

BACKGROUND Several studies found that early pancreatic atrophy detected by computed tomo-graphy(CT)within 6 months was associated with a high incidence of diabetes in patients with type-1 autoimmune pancreatitis(AIP)receiving steroid therapy;however,no long-term follow-up studies have been performed.AIM To investigate pancreatic volume(PV)changes using three dimensional(3D)-CT volumetry and their relationship with IgG4 and diabetes in patients with AIP.METHODS This retrospective study included 33 patients with type-1 AIP receiving steroid therapy.Patients were divided into diffuse(D-type)and mass-forming type(M-type)AIP.PV was determined by semi-automated 3D-CT volumetry,and changes between initial and follow-up values were calculated.The relationship between PV and serum IgG4 levels was analyzed by Spearman’s rank correlation.The PV atrophy ratio compared with the presumed normal PV at the time of last follow-up CT and its relationship with diabetes were investigated.RESULTS There were 16 D-type and 17 M-type patients with long-term follow-up(mean,95.8 months).The regression curve of mean relative PV change reduced exponentially and rapidly during the first 25 months and then more slowly in both groups.The overall cumulative pancreas re-enlargement rates at 1,3,5,7 and 10 years were 6.1%,12.2%,29.2%,47.5%and 55.0%,respectively.There was a moderate-to-very strong positive correlation(ρ≥0.4)between PV and serum IgG4 levels in nine(9/13,69.2%)patients.All 33 patients showed pancreatic atrophy(mean 59.3%)after long-term follow-up.Patients with D-type AIP had a significantly higher atrophy rate and higher incidence of diabetes than M-type patients(P<0.05).CONCLUSION PV change initially reduced exponentially and then more slowly and is considered an important factor associated with diabetes.Serum IgG4 levels were positively correlated with PV during follow-up.

A systematic review on the imaging findings in auditory neuropathy spectrum disorder

Purpose:The present systematic review examined imaging findings in the Auditory Neuropathy Spectrum Disorder(ANSD)population.Methods:Electronic databases such as Pub Med,Google Scholar,J Gate,and Science Direct were used to conduct a literature search.The articles retrieved through the literature search were assessed in two stages.In the first stage,title and abstract screening were done;in the second stage,a full-length article review was done.From the 379 shortlisted records,19 articles were chosen for the full-length review.Results:The selected articles performed imaging using Computerized tomography(CT)and magnetic resonance imaging(MRI).In most studies,cochlear nerve deficiency(CND)was the most prevalent anomaly in the ANSD group.Also,MRI was the imaging modality of choice recommended in most studies.It was also noted that CND was a characteristic feature of unilateral ANSD.Conclusion:From this systematic review,it is clear that integrating imaging studies into diagnostic protocol would help to understand the underlying pathology better and expedite decision-making and intervention for ANSD patients.

Three-dimensional finite element simulation and reconstruction of jointed rock models using CT scanning and photogrammetry

The geometry of joints has a significant influence on the mechanical properties of rocks.To simplify the curved joint shapes in rocks,the joint shape is usually treated as straight lines or planes in most laboratory experiments and numerical simulations.In this study,the computerized tomography (CT) scanning and photogrammetry were employed to obtain the internal and surface joint structures of a limestone sample,respectively.To describe the joint geometry,the edge detection algorithms and a three-dimensional (3D) matrix mapping method were applied to reconstruct CT-based and photogrammetry-based jointed rock models.For comparison tests,the numerical uniaxial compression tests were conducted on an intact rock sample and a sample with a joint simplified to a plane using the parallel computing method.The results indicate that the mechanical characteristics and failure process of jointed rocks are significantly affected by the geometry of joints.The presence of joints reduces the uniaxial compressive strength (UCS),elastic modulus,and released acoustic emission (AE) energy of rocks by 37%–67%,21%–24%,and 52%–90%,respectively.Compared to the simplified joint sample,the proposed photogrammetry-based numerical model makes the most of the limited geometry information of joints.The UCS,accumulative released AE energy,and elastic modulus of the photogrammetry-based sample were found to be very close to those of the CT-based sample.The UCS value of the simplified joint sample (i.e.38.5 MPa) is much lower than that of the CT-based sample (i.e.72.3 MPa).Additionally,the accumulative released AE energy observed in the simplified joint sample is 3.899 times lower than that observed in the CT-based sample.CT scanning provides a reliable means to visualize the joints in rocks,which can be used to verify the reliability of photogrammetry techniques.The application of the photogrammetry-based sample enables detailed analysis for estimating the mechanical properties of jointed rocks.

Convergent Data-Driven Regularizations for CT Reconstruction

The reconstruction of images from their corresponding noisy Radon transform is a typical example of an ill-posed linear inverse problem as arising in the application of computerized tomography(CT).As the(naive)solution does not depend on the measured data continuously,regularization is needed to reestablish a continuous dependence.In this work,we investigate simple,but yet still provably convergent approaches to learning linear regularization methods from data.More specifically,we analyze two approaches:one generic linear regularization that learns how to manipulate the singular values of the linear operator in an extension of our previous work,and one tailored approach in the Fourier domain that is specific to CT-reconstruction.We prove that such approaches become convergent regularization methods as well as the fact that the reconstructions they provide are typically much smoother than the training data they were trained on.Finally,we compare the spectral as well as the Fourier-based approaches for CT-reconstruction numerically,discuss their advantages and disadvantages and investigate the effect of discretization errors at differentresolutions.

Reliability of a computerized system for strabismus screening

AIM:To evaluate the reliability of Photo-Hirschberg screening for global strabismus performed by non-specialized personnel.METHODS:Participants at three sites were enrolled.One person at each site was trained in visual acuity measurement and use of the computerized system.Visual acuity was measured,and strabismus testing was performed using two flash photographs.All data from the three primary observers were sent to an experienced assistant researcher,who was blinded to the primary results,for re-evaluation.The primary and re-evaluation results of the Photo-Hirschberg screenings using weighted kappa for agreement were compared.RESULTS:The study included 181 participants(88 males and 93 females)and the results for primary and re-evaluation screenings were corresponded.Ten participants with contrasting results presented with unclear corneal light reflex.Sensitivity and specificity were 100%[95%confidence interval(CI):29.0%-100%]and 99.4%(95%CI:96.6%-100%),respectively,based on the Agresti test of the primary evaluation,considering the re-evaluated classification as true.CONCLUSION:The computerized system can be used for primary strabismus screening by non-specialized personnel,with 98.8%agreement with specialists.However,it cannot be used as a substitute for professional examination.

Study on sex differences and potential clinical value of threedimensional computerized tomography pelvimetry in rectal cancer patients

BACKGROUND Laparoscopic rectal cancer radical surgery is a complex procedure affected by various factors.However,the existing literature lacks standardized parameters for the pelvic region and soft tissues,which hampers the establishment of consistent conclusions.AIM To comprehensively assess 16 pelvic and 7 soft tissue parameters through computerized tomography(CT)-based three-dimensional(3D)reconstruction,providing a strong theoretical basis to address challenges in laparoscopic rectal cancer radical surgery.METHODS We analyzed data from 218 patients who underwent radical laparoscopic surgery for rectal cancer,and utilized CT data for 3D pelvic reconstruction.Specific anatomical points were carefully marked and measured using advanced 3D modeling software.To analyze the pelvic and soft tissue parameters,we emp-loyed statistical methods including paired sample t-tests,Wilcoxon rank-sum tests,and correlation analysis.RESULTS The investigation highlighted significant sex disparities in 14 pelvic bone parameters and 3 soft tissue parameters.Males demonstrated larger measurements in pelvic depth and overall curvature,smaller measurements in pelvic width,a larger mesorectal fat area,and a larger anterior-posterior abdominal diameter.By contrast,females exhibited wider pelvises,shallower depth,smaller overall curvature,and an increased amount of subcutaneous fat tissue.However,there were no significant sex differences observed in certain parameters such as sacral curvature height,superior pubococcygeal diameter,rectal area,visceral fat area,waist circumference,and transverse abdominal diameter.CONCLUSION The reconstruction of 3D CT data enabled accurate pelvic measurements,revealing significant sex differences in both pelvic and soft tissue parameters.This study design offer potential in predicting surgical difficulties and creating personalized surgical plans for male rectal cancer patients with a potentially“difficult pelvis”,ultimately improving surgical outcomes.Further research and utilization of these parameters could lead to enhanced surgical methods and patient care in laparoscopic rectal cancer radical surgery.

Computerized cognitive remediation therapy on cognitive impairment and social function in patients with chronic schizophrenia

BACKGROUND Patients with schizophrenia may have various disease manifestations,most of which gradually tend toward incurable chronic decline,leading to mental disability.The basic symptoms of the disease can impair social function,whereas long-term hospitalization produces hospitalization syndrome,causing serious damage to social function.AIM To investigate the effects of Computerized Cognitive Remediation Therapy(CCRT)on cognitive and social functioning in patients with chronic schizophrenia.METHODS A retrospective analysis of 120 patients with chronic schizophrenia in Shanghai Pudong New Area Mental Health Center was performed.They were divided into an intervention group(60 cases treated with CCRT combined with conventional medication)and a control group(60 cases treated with conventional medication).After treatment,effects on cognitive function and social roles were observed in both groups.The Positive and Negative Syndrome Scale(PANSS)was used to assess the patients'psychiatric symptoms.The Wisconsin Card Sorting Test(WCST)was used to assess the patients'cognitive functioning,and the Social Functioning Scale for Psychiatric Inpatients(SSPI)was used to assess the social functioning of the inpatient psychiatric patients.RESULTS No significant differences were observed in the PANSS,WCST,and SSPI intergroup scores before treatment(P>0.05).After 2,4,and 6 wk of therapy,general psychopathological factors,positive symptoms,negative symptoms,and total PANSS scores of PANSS in the intervention group were lower than in the control group(P<0.05).After 2,4,and 6 wk of treatment,the number of false responses,number of persistent bugs,and total responses in the WCST were significantly lower in the intervention group than in the control group(P<0.05),and the amount of completed classification was significantly higher than in the control group(P<0.05).After 2,4,and 6 wk of therapy,the SSPI scores were significantly greater than those of the controls(P<0.05).After 6 wk of treatment,the efficacy rates of the control and intervention groups were 81.67%and 91.67%,respectively.The curative effect in the intervention group was significantly higher than that in the control group(P<0.05).CONCLUSION CCRT can significantly improve cognitive function and social abilities in patients with chronic schizophrenia.

Use of the vertebrae and iliac bone as references for localizing the appendix vermiformis in computed tomography

BACKGROUND The appendix vermiformis is a part of the gastrointestinal tract,situated in the lower right quadrant of the abdomen.Acute appendicitis,acute inflammation of the appendix vermiformis,is the most common cause of acute abdomen requiring surgical intervention.Although computed tomography(CT)offers high diagnostic efficacy in assessing the appendix across various anatomical positions,it also involves radiation exposure.Reducing exposure factors and narrowing the field of view(FOV)are ways to decrease the radiation dose to the patient.To narrow the FOV,appendix locations within the population must be defined using metric markers.AIM To determine the location of the appendix vermiformis on CT using the vertebrae and the right iliac bone as anatomical landmarks.METHODS This retrospective study examined 470 patients presenting with abdominal pain who underwent abdominal CT scans between January 01,2015 and January 01,2018.Forty-three patients were excluded due to various reasons.The most superior and inferior points and the origin of the appendix were measured separately in relation to the vertebrae and right iliac bone for localization.The population was divided into normal and acute appendicitis groups,and the relationship between appendix location and anthropometric parameters relationship was examined.P values below 0.05 were considered statistically significant.RESULTS The final analysis included 427 adult patients(206 females and 221 males)with a mean age of 42.1±19.5 years.An ascending appendix course was the most common(90.4%).The appendix ranged from the L2 vertebral body level to the coccygeal vertebral level relative to the vertebrae.The appendix ranged between(−)140.5 mm and(+)87.4 mm relative to the right iliac bone.A negative correlation was found between patient age,height,body mass index,and the highest and lowest points of the appendix in regard to the vertebrae.CONCLUSION The study’s findings unveiled the locations of the appendix in the population in relation to the bony anatomical landmarks.These data can be used as the basis for future research aimed at reducing patient exposure to ionizing radiation.

Application value of high-pressure-resistant peripherally inserted central catheters in enhanced computer tomography of diabetic patients with malignant tumors

BACKGROUND Individuals with diabetes mellitus have a higher risk of developing malignant tumors,and diagnosing these tumors can be challenging.AIM To confirm the benefits of using peripherally inserted central catheters(PICCs)in contrast-enhanced computerized tomography(CECT)for diagnostic imaging in diabetic patients with malignant tumors and to provide a research basis for follow-up research.METHODS This retrospective study analyzed 204 diabetic patients with malignancies treated at The Second Affiliated Hospital,Jiangxi Medical College,Nanchang University,from January 2024 to June 2024.The patients were divided into two groups:A control group(n=102)with indwelling peripheral intravenous catheters and a research group(n=102)with high-pressure-resistant PICC.The study compared baseline data,the incidence of iodine contrast extravasation during CECT,the incidence of adverse events(discomfort,redness and swelling at the puncture site,and blood oozing),imaging quality,nursing time,intubation success rate,number of venipuncture attempts,and catheter maintenance cost.RESULTS Male patients accounted for 51.96%in the control group and 55.88%in the research group;the average age was(59.68±11.82)years in the control group and(61.41±12.92)years in the research group;the proportions of lung cancer,colorectal cancer,and gastric cancer patients in the control group were 42.16%,38.24%,and 19.61%,respectively,while those in the research group were 34.31%,37.25%,and 28.43%,respectively.Except for the gender distribution,age,and cancer type mentioned above,other general information such as underlying diseases,puncture location,and long-term chemotherapy shows no significant differences as tested(P>0.05).The results showed that the research group had significantly reduced incidence of iodine contrast extravasation(7 vs 1,P=0.031),similar incidence of adverse events(11 vs 7,P=0.324),reduced nursing time[(18.50±2.68)minutes vs(13.26±3.00)minutes,P=0.000],fewer venipuncture attempts[(2.21±0.78)times vs(1.49±0.58)times,P=0.000],lower catheter maintenance cost[(1251.79±205.47)China yuan(CNY)vs(1019.25±117.28)CNY,P=0.000],increased intubation success rate(16.67%vs 58.82%,P=0.000),and better imaging quality(85.29%vs 94.12%,P=0.038).CONCLUSION High-pressure-resistant PICCs can lessen the physical burden of diabetic patients during nursing,reduce treatment costs,and improve the efficiency and quality of imaging for diagnosis malignant tumors.

The computerized LASSI-BC Test versus the Standard LASSI-L Paper-and-Pencil Version in Community-Based-Samples

Proactive Semantic Interference (PSI) and failure to recover from PSI (frPSI), are novel constructs assessed by the LASSI-L. These measures are sensitive to cognitive changes in early Mild Cognitive Impairment (MCI) and preclinical AD determined by Aβ load using PET. The goal of this study was to compare a new computerized version of the LASSI-L (LASSI-Brief Computerized) to the standard paper-and-pencil version of the test. In this study, we examined 110 cognitively unimpaired (CU) older adults and 79 with amnestic MCI (aMCI) who were administered the paper-and-pencil form of the LASSI-L. Their performance was compared with 62 CU older adults and 52 aMCI participants examined using the LASSI-BC. After adjustment for covariates (degree of initial learning, sex, education, and language of evaluation) both the standard and computerized versions distinguished between aMCI and CU participants. The performance of CU and aMCI groups using either form was relatively commensurate. Importantly, an optimal combination of Cued B2 recall and Cued B1 intrusions on the LASSI-BC yielded an area under the ROC curve of .927, a sensitivity of 92.3% and specificity of 88.1%, relative to an area under the ROC curve of .815, a sensitivity of 72.5%, and a specificity of 79.1% obtained for the paper-and-pencil LASSI-L. Overall, the LASSI-BC was comparable, and in some ways, superior to the paper-and-pencil LASSI-L. Advantages of the LASSI-BC include a more standardized administration, suitability for remote assessment, and an automated scoring mechanism that can be verified by a built-in audio recording of responses.

A Framework for Cloud Validation in Pharma

The pharmaceutical industry’s increasing adoption of cloud-based technologies has introduced new challenges in computerized systems validation (CSV). This paper explores the evolving landscape of cloud validation in pharmaceutical manufacturing, focusing on ensuring data integrity and regulatory compliance in the digital era. We examine the unique characteristics of cloud-based systems and their implications for traditional validation approaches. A comprehensive review of current regulatory frameworks, including FDA and EMA guidelines, provides context for discussing cloud-specific validation challenges. The paper introduces a risk-based approach to cloud CSV, detailing methodologies for assessing and mitigating risks associated with cloud adoption in pharmaceutical environments. Key considerations for maintaining data integrity in cloud systems are analyzed, particularly when applying ALCOA+ principles in distributed computing environments. The article presents strategies for adapting traditional Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ) models to cloud-based systems, highlighting the importance of continuous validation in dynamic cloud environments. The paper also explores emerging trends, including integrating artificial intelligence and edge computing in pharmaceutical manufacturing and their implications for future validation strategies. This research contributes to the evolving body of knowledge on cloud validation in pharmaceuticals by proposing a framework that balances regulatory compliance with the agility offered by cloud technologies. The findings suggest that while cloud adoption presents unique challenges, a well-structured, risk-based approach to validation can ensure the integrity and compliance of cloud-based systems in pharmaceutical manufacturing.

Development of a Framework for Equipment Health Management in the Mining Industries in Zambia

The Zambian mining industry is crucial to the national economy but struggles with inconsistent equipment maintenance practices. This study developed an Equipment Maintenance Management Framework (EMMF) tailored to the industry’s needs. Using surveys, interviews, and on-site visits at eight major mining companies, we identified significant variations in maintenance strategies, CMMS usage, and reliability engineering. The EMMF prioritizes predictive maintenance, efficient CMMS implementation, ongoing training, and robust reliability engineering to shift from reactive to proactive maintenance. We recommend adopting continuous improvement practices and data-driven decision-making based on performance metrics, with a phased EMMF implementation aligning maintenance with strategic business objectives. This framework is poised to enhance operational efficiency, equipment reliability, and safety, fostering sustainable growth in the Zambian mining sector.

计算机化自适应测验(CAT)的发展和前景展望(续)

三、CAT中对的估计（一）MLE（极大似然估计法）假设一个能力水平为θ的被试对n道项目X1,X2,…,Xn作答。θ的估计可以通过使（8）式所示的似然函数最大化的方式来得到。令（?）n为此时所得的θ估计。显然（?）n也是（9）式的极大似然估计。已知在一定的条件下,（?）n符合渐进正态,其均值为θ,方差近似为I-1n（（?）n）。目前的CAT设计大多通过递归方式在被试回答一个新的项目之后得到最新的θ估计,并根据信息最大化法抽取下一个项目。

Applied Strain Field on Microstructure Optimization of Ti-Al-Nb Alloy Computer Simulated by Phase Field Approach

The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain direction onthe microstructure and volume fraction of the O-phase precipitates. It is found that altering applied strain directioncan modify microstructure of Ti-25Al-10～12Nb (at. pct) alloy during α_2→O-phase transformation effectively andfull laminate microstructure in the Ti-25Al-10Nb (at. pct) alloy can be realized by an applied strain only along thedirection 30°away from the α_2 phase <1010> in magnitude equivalent to the stress-free transformation strain. Thesimulation also shows that not only the magnitude of applied strain but also the applied strain direction influencesthe O-phase volume fraction and the effect of strain direction on the volume fraction is up to 25%.

心脏CT综合仿真模型及快速图像重建

首先介绍了胸部和运动两种CT(Computerized Tomography)心脏仿真模型,通过对原模型进行简化、改进和合并,定义了新的心脏综合模型。其次,通过坐标变换和心脏运动的简化实现了模型投影值的快速计算。最后,通过多周期采集模型的投影数据,由滤波反投影算法重建图像,仿真结果表明了模型及重建方法的有效性。

Construction of a database of average cross-sections in Chinese proximal femurs

The process of constructing a database of average cross-sections in Chinese proximal femurs is described. The main goal of creating the database is for designing hip stems for Chinese patients. Methods for constructing the database are introduced. According to some existing software and programs developed by the authors, a database of average cross-sections in Chinese proximal femurs was built based on CT images of eighty femur-specimens. 3-D shape of a patient's proximal femurs can be reconstructed according to the database and X-ray radiographs. Theoretical analyses and results of clinical application indicate that the database can be used to design hip stems for Chinese patients.

A New Simulation Method for 3D Propellant Grain Burn Analysis of Solid Rocket Motor

Describes a new computer program (Regress-3D) to simulate the regression of complex 3D grain cavity and calculate the burning surface area. It has a large region of applicability in solid rocket motor design and has made new improvements compared with other available codes. User can easily and rapidly build his initial grain shapes and then obtain geometric information of his design. Considering with the calclulting results, redesigning can be performed as desire until reaching at the satisfied result. Advantages and disadvantages of this method are also discussed.