模式动物线虫的学习与学习抉择行为

线虫因为其简单的体系和对于诸如接触、味道、气味和温度等外界刺激的敏感反映能力,日益成为受人瞩目的研究行为可塑性的模式动物。目前认为,线虫中的学习包括非联想与联想学习两大类,且存在至少6种形式化学趋向性介导的联想学习。同时,三种研究体系已经被开发出来用于学习抉择的研究。本文讨论了线虫中学习与学习抉择的形式、研究模型及其遗传与分子调控机制。     

PBL教学法在儿内科教学中的实践与探索

目的 探索新的高等医学教育的教学方式，以适应医学科学的发展及医学模式的转变。方法 在临床医学院三个大班共182名本科生的《儿内科学》教学中，开展以问题为基础的学习(PBL)教学法尝试，每班分成三个小组，在三位教师辅导下，“以问题为基础”对病例进行讨论学习，要求学生课前阅读教科书和有关参考文献。结果 PBL教学法使学生掌握有关该疾病的更多知识，并在期终考试的成绩及不定期的临床测验中得到证实。结论 PBL教学法有利于调动学生的学习积极性、主动性，有利于培养学生的自学能力和创新精神，在教与学两方面促进了教学质量的提高，受到学生和教师的普遍认可，值得进一步实践和推广。     

两种电子教材开发方式的对比研究

介绍了移动学习领域以iBook Author为依托和基于Web的两种电子教材开发方式,并将两种开发方式进行对比、总结出各自的优缺点,为今后的电子教材开发人员提供参考。     

案例教学法在普通外科实习医师教学中的应用

普通外科是所有外科实习科室中最重要的科室之一,如何在较短的实习时间内将普通外科常见病和多发病的诊疗知识掌握好,这是普通外科实习教学教师必须面对的问题.采用案例教学法与传统教学法进行教学效果比较研究,发现前者能明显提高普通外科实习质量.     

TAS1R3 and TAS2R38 Polymorphisms Affect Sweet Taste Perception: An Observational Study on Healthy and Obese Subjects

Background: The inter-individual differences in taste perception find a possible rationale in genetic variations. We verified whether the presence of four different single nucleotide polymorphisms (SNPs) in genes encoding for bitter (TAS2R38; 145G > C; 785T > C) and sweet (TAS1R3; −1572C > T; −1266C > T) taste receptors influenced the recognition of the basic tastes. Furthermore, we tested if the allelic distribution of such SNPs varied according to BMI and whether the associations between SNPs and taste recognition were influenced by the presence of overweight/obesity. Methods: DNA of 85 overweight/obese patients and 57 normal weight volunteers was used to investigate the SNPs. For the taste test, filter paper strips were applied. Each of the basic tastes (sweet, sour, salty, bitter) plus pure rapeseed oil, and water were tested. Results: Individuals carrying the AV/AV diplotype of the TAS2R38 gene (A49P G/G and V262 T/T) were less sensitive to sweet taste recognition. These alterations remained significant after adjustment for gender and BMI. Moreover, a significant decrease in overall taste recognition associated with BMI and age was found. There was no significant difference in allelic distribution for the investigated polymorphisms between normal and overweight/obese patients. Conclusions: Our findings suggest that overall taste recognition depends on age and BMI. In the total population, the inter-individual ability to identify the sweet taste at different concentrations was related to the presence of at least one genetic variant for the bitter receptor gene but not to the BMI.     

Prediction of Compressive Strength of Sustainable Foam Concrete Using Individual and Ensemble Machine Learning Approaches

The entraining and distribution of air voids in the concrete matrix is a complex process that makes the mechanical properties of lightweight foamed concrete (LFC) highly unpredictable. To study the complex nature of aerated concrete, a reliable and robust prediction model is required, employing different machine learning (ML) techniques. This study aims to predict the compressive strength of LFC by using a support vector machine (SVM) as an individual learner along with bagging, boosting, and random forest (RF) as a modified ensemble learner. For that purpose, a database of 191 data points was collected from published literature, where the mix design ingredients, i.e., cement content, sand content, water to cement ratio, and foam volume, were chosen to predict the compressive strength of LFC. The 10-K fold cross-validation method and different statistical error and regression tools, i.e., mean absolute error (MAE), root means square error (RMSE), and coefficient of determinant (R²), were used to evaluate the performance of the developed ML models. The modified ensemble learner (RF) outperforms all models by yielding a strong correlation of R² = 0.96 along with the lowest statistical error values of MAE = 1.84 MPa and RMSE = 2.52 MPa. Overall, the result suggests that the ensemble learners would significantly enhance the performance and robustness of ML models.     

Prediction of the Uric Acid Component in Nephrolithiasis Using Simple Clinical Information about Metabolic Disorder and Obesity: A Machine Learning-Based Model

There is a great need for a diagnostic tool using simple clinical information collected from patients to diagnose uric acid (UA) stones in nephrolithiasis. We built a predictive model making use of machine learning (ML) methodologies entering simple parameters easily obtained at the initial clinical visit. Socio-demographic, health, and clinical data from two cohorts (A and B), both diagnosed with nephrolithiasis, one between 2012 and 2016 and the other between June and December 2020, were collected before nephrolithiasis treatment. A ML-based model for predicting UA stones in nephrolithiasis was developed using eight simple parameters—sex, age, gout, diabetes mellitus, body mass index, estimated glomerular filtration rate, bacteriuria, and urine pH. Data from Cohort A were used for model training and validation (ratio 3:2), while data from Cohort B were used only for validation. One hundred and forty-six (13.3%) out of 1098 patients in Cohort A and 3 (4.23%) out of 71 patients in Cohort B had pure UA stones. For Cohort A, our model achieved a validation AUC (area under ROC curve) of 0.842, with 0.8475 sensitivity and 0.748 specificity. For Cohort B, our model achieved 0.936 AUC, with 1.0 sensitivity, and 0.912 specificity. This ML-based model provides a convenient and reliable method for diagnosing urolithiasis. Using only eight readily available clinical parameters, including information about metabolic disorder and obesity, it distinguished pure uric acid stones from other stones before treatment.     

以框架为基础的教学／自学模式实施效果的初步评估

北京协和医学院医学微生物教学中,采用以框架为基础的教学／自学模式,82名学生参与其中。本文对以框架为基础的教学／自学模式在微生物学教学中的实施效果进行了评估,主要从8个方面评估了学生组织自学后的自我展示情况,同时学生也从10个方面对该教学／自学模式的实施效果进行了匿名评估。结果显示,学生自我展示情况各项得分（满分为5分）为（4．30±0．33）分～（4．66±0．21）分;学生匿名评估的各项得分（满分为4分）为（3．13±0．75）分～（2．33±0．79）分。实践证明,学生在以框架为基础的自学训练中表现良好,大部分学生对此教学／自学模式持正面和积极的看法,此教学／自学模式比较适用于现阶段本学院的医学微生物学教学。     

Testing for anosmia and ageusia in patients presenting to the emergency department with suspected coronavirus disease 2019 in Saudi Arabia

ObjectiveThis study investigated the role of objective olfactory dysfunction (OD) and gustatory dysfunction (GD) testing among patients with suspected coronavirus disease 2019 (COVID-19) who presented with respiratory symptoms.MethodsA prospective, blinded, observational study was conducted in the emergency units of two tertiary hospitals. Participants were asked to identify scents in the pocket smell test (PST) and flavors in four different solutions in the gustatory dysfunction test (GDT). We assessed the level of agreement between objective findings and self-reported symptoms. We evaluated the diagnostic accuracy of chemosensory dysfunction for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.ResultsOf 250 participants, 74 (29.6%) were SARS-CoV-2-positive. There was slight agreement between self-reported symptoms and objective findings (kappa = 0.13 and 0.10 for OD and GD, respectively). OD assessed by the PST was independently associated with COVID-19 (adjusted odds ratio = 1.89, 95% confidence interval, 1.04–3.46). This association was stronger when OD was combined with objective GD, cough, and fever (adjusted odds ratio = 7.33, 95% confidence interval, 1.17–45.84).ConclusionsNeither the PST nor GDT alone are useful screening tools for COVID-19. However, a diagnostic scale based on objective OD, GD, fever, and cough may help triage patients with suspected COVID-19.     

PBL联合PDG在临床医学系高年级医学生中的应用

目的 研究以问题为导向的教学方法 (PBL)联合问题—讨论—指导(PDG)教学模式在临床医学系高年级医学生培养中的应用效果.方法 选取2018年1月—2019年1月临床医学系高年级医学生134例,按随机数字表分为对照组(67例)与研究组(67例),对照组学生采用传统的教学模式,研究组学生采用PBL联合PDG教学模式,比...