Feedback, fairness, and validity: effects of disclosing and reusing multiple-choice questions in medical schools.

BACKGROUND: Disclosure of items used in multiple-choice-question (MCQ) exams may decrease student anxiety and improve transparency, feedback, and test-enhanced learning but potentially compromises the reliability and fairness of exams if items are eventually reused. Evidence regarding whether disclosure and reuse of test items change item psychometrics is scarce and inconclusive. METHODS: We retrospectively analysed difficulty and discrimination coefficients of 10,148 MCQ items used between fall 2017 and fall 2019 in a large European medical school in which items were disclosed from fall 2017 onwards. We categorised items as 'new'; 'reused, not disclosed'; or 'reused, disclosed'. For reused items, we calculated the difference from their first ever use, that is, when they were new. Differences between categories and terms were analysed with one-way analyses of variance and independent-samples t tests. RESULTS: The proportion of reused, disclosed items grew from 0% to 48.4%; mean difficulty coefficients increased from 0.70 to 0.76; that is, items became easier, P < .001, ηp2 = 0.011. On average, reused, disclosed items were significantly easier (M = 0.83) than reused, not disclosed items (M = 0.71) and entirely new items (M = 0.66), P < .001, ηp2 = 0.087. Mean discrimination coefficients increased from 0.21 to 0.23; that is, item became slightly more discriminating, P = .002, ηp2 = 0.002. CONCLUSIONS: Disclosing test items provides the opportunity to enhance feedback and transparency in MCQ exams but potentially at the expense of decreased item reliability. Discrimination was positively affected. Our study may help weigh advantages and disadvantages of using previously disclosed items.

Evaluation of a 3D-MC examination format in anatomy.

INTRODUCTION: The quality of education in medical anatomy is a fundamental pillar of good clinical practice. Current reforms of the medical curriculum have resulted in major methodological changes in the teaching and testing of anatomy. A number of recent studies have however described a decrease in positive metrics of anatomical knowledge among students so taught. It has been suggested that the reduced anatomical knowledge measured in these studies may endanger patient safety. As proxy measures of exam quality, evaluation of the levels of students 'achievement in the examinations, assessment of the subjectively perceived level of question difficulty and analysis of exam satisfaction are each suitable parameters of investigation of medical education. MATERIAL AND METHODS: To address these issues with regard to medical education at the Charité-Universitätsmedizin Berlin, we have analyzed students' levels of achievement in the anatomical Three Dimensional Multiple Choice (hereafter, 3D-MC)-examination of 2,015 students matriculated in medical studies from Summer Semester of 2014 through Summer Semester of 2017. We either compared students' achievement levels of identical 3D-MC questions using models or prepared anatomical specimen. Furthermore, we have analyzed the type and frequency of cognitive levels used in the anatomical questions in relation to the students' level of achievement. Finally, we conducted an anonymous survey to measure students' (n = 207) and instructors' (n = 16) satisfaction with the 3D-MC-examination in comparison to other employed anatomical testing strategies. RESULTS: Students' achievement is significantly enhanced with anatomical questions using models relative to those utilizing anatomical specimen. Over 80% of the anatomical questions in the 3D-MC-examinations assessed the lowest cognitive levels and higher cognitive question levels were accompanied by a significant decrease of the levels of students' performance. Our survey further revealed that both, students and instructors preferred the practical examinations in anatomy and that the difficulty levels of the 3D-MC-examination was perceived as being the lowest in comparison to the other anatomical testing strategies. DISCUSSION: Testing levels of anatomical understanding using anatomical models is not comparable to human specimen, and thus using specimen before models should be preferred to learn and test close to an authentic medical situation. The application of anatomical models and low cognitive question levels in the examination reduces the subjectively perceived level of difficulty, encourages superficial learning, and therefore decreases the retention of anatomical knowledge. CONCLUSION: Although students and instructors prefer practical examinations in anatomy, the current development does not reflect these results. Therefore, it would be recommendable to rethink the development of anatomical testing strategies based on the existing evidence.

Rates of motorcycle helmet use and reasons for non-use among adults and children in Luang Prabang, Lao People's Democratic Republic.

BACKGROUND: Motorcycles make up 81 % of the total vehicle population and 74 % of road traffic deaths in Lao PDR. Helmets reduce the risk and severity of injuries resulting from motorcycle accidents by 72 %. Although Lao law mandates motorcycle helmet use among drivers and passengers, the prevalence of helmet use in Luang Prabang, Lao PDR is unknown. This project aimed to measure the prevalence of motorcycle helmet use among riders (i.e., drivers and passengers) in Luang Prabang. METHODS: An observational survey in Luang Prabang was conducted in February 2015 to measure the prevalence of motorcycle helmet use among drivers and passengers. Additionally, non-helmet wearing riders were surveyed to identify the reasons for helmet non-use. RESULTS: Of 1632 motorcycle riders observed, only 16.2 % wore helmets. Approximately 29 % of adults wore helmets while less than 1 % of all children wore helmets. When surveyed about attitudes towards helmet use, the majority of adult drivers indicated that they did not like how adult helmets feel or made them look. Additionally, almost half of motorcyclists who did not own child helmets reported that their child was too young to wear a helmet. CONCLUSIONS: Our finding that children wear helmets at significantly lower rates compared to adults is consistent with findings from neighboring countries in Southeast Asia. Results of this study have implications for public health campaigns targeting helmet use, especially among children.

Carbon source control of the phosphorylation state of the Bacillus subtilis carbon-flux regulator Crh in vivo.

Bacillus subtilis possesses carbon-flux regulating histidine protein (Crh), a paralog of the histidine protein (HPr) of the phosphotransferase system (PTS). Like HPr, Crh becomes (de)phosphorylated in vitro at residue Ser46 by the metabolite-controlled HPr kinase/phosphorylase HPrK/P. Depending on its phosphorylation state, Crh exerts regulatory functions in connection with carbohydrate metabolism. So far, knowledge on phosphorylation of Crh in vivo has been limited and derived from indirect evidence. Here, we studied the dynamics of Crh phosphorylation directly by non-denaturing gel electrophoresis followed by Western analysis. The results confirm that HPrK/P is the single kinase catalyzing phosphorylation of Crh in vivo. Accordingly, phosphorylation of Crh is triggered by the carbon source as observed previously for HPr, but with some differences. Phosphorylation of both proteins occurred during exponential growth and disappeared upon exhaustion of the carbon source. During exponential growth, ~80% of the Crh molecules were phosphorylated when cells utilized a preferred carbon source. The reverse distribution, i.e. around 20% of Crh molecules phosphorylated, was obtained upon utilization of less favorable substrates. This clear-cut classification of the substrates into two groups has not previously been observed for HPr(Ser)~P formation. The likely reason for this difference is the additional PTS-dependent phosphorylation of HPr at His15, which limits accumulation of HPr(Ser)~P.

Bioaccessibility of carotenoids and vitamin e from pasta: evaluation of an in vitro digestion model.

The present investigation aimed to expand the knowledge of bioaccessibility of carotenoids, tocopherols, and tocotrienols from cereal products such as pasta. Because most of the published approaches assessing the bioaccessibility of lipophilic micronutrients dealt with fruits and vegetables, a prevalent in vitro digestion procedure was modified. Additionally, several digestion parameters were evaluated with regard to their impact on the bioaccessibility of carotenoids and vitamin E from pasta. Overall, the estimated values were highly dependent on the amount of bile extract present in the digestive medium and to a lesser extent on the simulated gastric pH and the incubation time with digestive enzymes. The bioaccessibility of carotenoids and vitamin E from durum wheat pasta was quite high (71 ± 5 and 70 ± 4%, respectively), whereas these micronutrients were considerably less accessible from pasta containing 10% eggs (57 ± 1 and 49 ± 5%, respectively).

Contents of vitamin C, carotenoids, tocopherols, and tocotrienols in the subtropical plant species Cyphostemma digitatum as affected by processing.

The subtropical plant species Cyphostemma digitatum, Vitaceae, is used in central Yemen in traditional medicine, as a culinary herb, and as a source of food flavoring. The contents of vitamin C, vitamin E, and carotenoids and changes caused by common processing were investigated. Carotenoids were determined by reversed phase C30-high-performance liquid chromatography (HPLC) with diode array detection at 470 nm, while tocopherols and tocotrienols were analyzed by using normal phase HPLC with fluorescence detection (excitation, 292 nm; emission, 330 nm). Ascorbic acid was determined spectrophotometrically after reaction with DNP by measuring the absorbance at 520 nm. For the raw material and for the processed commercial food product, both in dried form, reasonable quantities of carotenoids were found in the raw material as follows: lutein, 18.89 +/- 0.73 mg/100 g; zeaxanthin, 9.46 +/- 0.30 mg/100 g; canthaxanthin, 0.21 +/- 0.01 mg/100 g; beta-cryptoxanthin, 0.67 +/- 0.03 mg/100 g; and beta-carotene, 14.60 +/- 0.46 mg/100 g. Household processing reduced the carotenoid contents dramatically; only beta-carotene sustained the processing. Likewise, vitamin C, 49.50 +/- 0.01 mg/100 g in the raw material and 20.30 +/- 0.02 mg/100 g in the processed material, was affected negatively by processing; only 41% was retained after processing. In contrast, the outstanding high content of vitamin E, 82.74 +/- 0.63 mg/100 g in the raw material, was increased by processing to 101.20 +/- 1.38 mg/100 g; it was found in different forms, some of which were rare in other sources.

Subcellular localization and integration activities of rous sarcoma virus reverse transcriptase.

Reverse transcriptases (RTs) alphabeta and beta from avian Rous sarcoma virus (RSV) harbor an integrase domain which is absent in nonavian retroviral RTs. RSV integrase contains a nuclear localization signal which enables the enzyme to enter the nucleus of the cell in order to perform integration of the proviral DNA into the host genome. In the present study we analyzed the subcellular localization of RSV RT, since previous results indicated that RSV finishes synthesis of the proviral DNA in the nucleus. Our results demonstrate that the heterodimeric RSV RT alphabeta and the beta subunit, when expressed independently, can be detected in the nucleus, whereas the separate alpha subunit lacking the integrase domain is prevalent in the cytoplasm. These data suggest an involvement of RSV RT in the transport of the preintegration complex into the nucleus. In addition, to analyze whether the integrase domain, located at the carboxyl terminus of beta, exhibits integration activities, we investigated the nicking and joining activities of heterodimeric RSV RT alphabeta with an oligodeoxynucleotide-based assay system and with a donor substrate containing the supF gene flanked by the viral long terminal repeats. Our data show that RSV RT alphabeta is able to perform the integration reaction in vitro; however, it does so with an estimated 30-fold lower efficiency than the free RSV integrase, indicating that RSV RT is not involved in integration in vivo. Integration with RSV RT alphabeta could be stimulated in the presence of human immunodeficiency virus type 1 nucleocapsid protein or HMG-I(Y).