Effects of reflection and immediate feedback to improve clinical reasoning of medical students in the assessment of dermatologic conditions: a randomised controlled trial

There are few studies that directly compared different interventions to improve medical students clinical reasoning for dermatologic conditions. To investigate the effectiveness of adding practice with reflection and immediate feedback on traditional dermatology electives in improving medical students ability in evaluating skin lesions. The participants were fourth-year medical students of Seoul National University College of Medicine, Korea, who were enrolled to take a 2-week dermatology elective course (n = 87). Students were assigned to one of the three educational interventions: 2-h training involving 10 written clinical cases (experimental); 1-h lecture and 1-h outpatient clinic (lecture); and 2-h outpatient clinic (no intervention). Before and at the end of rotation, diagnostic accuracy was estimated using 20 written clinical cases with photographs (10 novel cases presented in diagnostic training [training set], 10 cases with diagnoses not included in training [control set]). There was a significant interaction effect of intervention×set×time. A post hoc analysis indicated that the students in the experimental group outperformed students in the other two groups only in the training set of the final tests; after completing the 2-week rotation, for the training set, the mean score was higher in the experimental group (7.5 ± 1.3) than in the lecture (5.7 ± 1.6) and no intervention (5.6 ± 1.3) groups, producing an effect size of 1.2 standard deviation (SD) and 1.5 SD, respectively. Practicing written clinical cases with reflection and feedback is superior to a lecture-based approach and yields additional benefits to a dermatology elective, thereby enhancing medical students ability to accurately diagnose skin lesions. ClinicalTrials.gov, NCT03472001. Registered 21 March 2018.This work was supported by a clinical research grant-in-aid from the Seoul Metropolitan Government Seoul National University (SMG-SNU) Boramae Medical Center (03–2018-7). The funder had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publicatio

Percutaneous radiofrequency ablation for hepatic tumors: factors affecting baseline impedance

PurposeWe aimed to evaluate factors that affect baseline impedance of percutaneous radiofrequency ablation.MethodsIn this retrospective study, we analyzed 51 patients with 55 hepatic tumors from November 2015 until April 2018. We measured the baseline impedance nine times with three adjustable tip sizes (2 cm, 2.5 cm, 3 cm) and three different pad locations (two pads attached on the thigh, four on the thigh, two on the back). The first roll-off time was measured with two grounding pads attached on the back. Body mass index, cirrhotic or non-cirrhotic liver parenchyma, previous procedure, tumor location, artificial ascites, active tip size, and the pad location were evaluated as potential factors affecting baseline impedance using the Mann–Whitney U test, t-test and analysis of variance test.ResultsComplete radiofrequency ablation was achieved in 51 patients. Body mass index (p = 0.897), cirrhotic or non-cirrhotic liver parenchyma (p = 0.767), previous procedure (p = 0.957), tumor location (p = 0.906), and artificial ascites (p = 0.882) did not significantly affect baseline impedance. Grounding pads located on the back showed the lowest baseline impedance (p < 0.001). Increase in active tip size showed gradual decrease in baseline impedance (p = 0.016).ConclusionThe factors affecting baseline impedance were the pad location and the tip size. Positioning pads on the back lowers the baseline impedance and can shorten the first roll-off time, ultimately resulting in reduced total ablation time

A Spinal Cord Astrocytoma and Its Concurrent Osteoblastic Metastases at the Time of the Initial Diagnosis: a Case Report and Literature Review

Bone metastasis from a spinal cord astrocytoma has been reported only twice in the English medical literature. It is generally known that bone metastasis is found after the initial diagnosis with/without intervening surgery rather than being found at the time of the diagnosis of astrocytoma. The purpose of this article is to report for the first time a case of concurrent bone metastasis from a spinal cord astrocytoma at the time of diagnosing the spinal cord astrocytoma

An Area Efficient Thermal Energy Harvester with Reconfigurable Capacitor Charge Pump for IoT Applications

Renewable energy sources are promising alternatives to a battery. Due to the varying power profile of renewable energy sources, an energy harvester needs the different power management techniques including boosting the small input voltage. The awareness of the demand, this thesis introduces an integrated energy harvester system targeting Internet of Things (IoT) sensor applications such as a wireless temperature sensor. The proposed design extracts energy from a thermal energy generator (TEG), and provides the regulated output voltage. To ensure the maximum power extraction, the proposed energy harvester includes multiple circuit level techniques. First, the reconfigurable capacitor charge pump distributes on-chip capacitors to required step-up stages. This approach optimizes the silicon area by utilizing 100% on-chip capacitors regardless of a charge pump conversion gain. Second, the design is capable of 3 dimensional Maximum Power Point Tracking (MPPT), matching a source impedance to input impedance of an energy harvest source. Thus, the proposed energy harvester is able to extract power from a small form factor TEG, having low source impedance (1 Ω). With the increased matching range, up to 500 µW is available at the output for IoT applications. Experimental results show an end-to-end power efficiency of 64% @ 1 V output voltage, and the input impedance matching range of 1 Ω–5 kΩ. The energy harvester was fabricated in 130 nm Complementary Metal-Oxide-Semiconductor (CMOS) standard technology, and occupies 0.835 mm²

An Area Efficient Thermal Energy Harvester with Reconfigurable Capacitor Charge Pump for IoT Applications

Renewable energy sources are promising alternatives to a battery. Due to the varying power profile of renewable energy sources, an energy harvester needs the different power management techniques including boosting the small input voltage. The awareness of the demand, this thesis introduces an integrated energy harvester system targeting Internet of Things (IoT) sensor applications such as a wireless temperature sensor. The proposed design extracts energy from a thermal energy generator (TEG), and provides the regulated output voltage. To ensure the maximum power extraction, the proposed energy harvester includes multiple circuit level techniques. First, the reconfigurable capacitor charge pump distributes on-chip capacitors to required step-up stages. This approach optimizes the silicon area by utilizing 100% on-chip capacitors regardless of a charge pump conversion gain. Second, the design is capable of 3 dimensional Maximum Power Point Tracking (MPPT), matching a source impedance to input impedance of an energy harvest source. Thus, the proposed energy harvester is able to extract power from a small form factor TEG, having low source impedance (1 Ω). With the increased matching range, up to 500 µW is available at the output for IoT applications. Experimental results show an end-to-end power efficiency of 64% @ 1 V output voltage, and the input impedance matching range of 1 Ω–5 kΩ. The energy harvester was fabricated in 130 nm Complementary Metal-Oxide-Semiconductor (CMOS) standard technology, and occupies 0.835 mm²

THE ENHANCED REDUCTION OF BROMATE BY HIGHLY REACTIVE AND DISPERSIVE GREEN NANO-ZEROVALENT IRON (G-NZVI) SYNTHESIZED WITH ONION PEEL EXTRACT

In this study, novel green nano-zerovalent iron (G-NZVI) is synthesized for the first time using onion peel extract for the prevention of rapid surface oxidation and the enhancement of particle dispersibility with a high reductive capacity. The results from various surface analyses revealed that the spherical shape of G-NZVI was fully covered by the onion peel extract composed of polyphenolic compounds with C]C– C]C unsaturated carbon, C]C, C–O, and O–H bonds, resulting in high mobility during column chromatography. Furthermore, the obtained G-NZVI showed the complete removal of 50 mg L 1 of bromate (BrO3 ) in 2 min under both aerobic (k ¼ 4.42 min 1 ) and anaerobic conditions (k ¼ 4.50 min 1 ), showing that G-NZVI had outstanding oxidation resistance compared to that of bare NZVI. Moreover, the observed performance of G-NZVI showed that it was much more reactive than other well-known reductants (e.g., Fe and Co metal organic frameworks), regardless of whether aerobic or anaerobic conditions were used. The effects of G-NZVI loading, the BrO3 concentration, and pH on the BrO3 removal kinetics using G-NZVI were also investigated in this study. The results provide the novel insight that organic onion peel waste can be reused to synthesize highly reactive anti-oxidative nanoparticles for the treatment of inorganic chemical species and heavy metals in water and wastewater

THE ENHANCED REDUCTION OF BROMATE BY HIGHLY REACTIVE AND DISPERSIVE GREEN NANO-ZEROVALENT IRON (G-NZVI) SYNTHESIZED WITH ONION PEEL EXTRACT†

In this study, novel green nano-zerovalent iron (G-NZVI) is synthesized for the first time using onion peel extract for the prevention of rapid surface oxidation and the enhancement of particle dispersibility with a high reductive capacity. The results from various surface analyses revealed that the spherical shape of G-NZVI was fully covered by the onion peel extract composed of polyphenolic compounds with C[double bond, length as m-dash]C–C[double bond, length as m-dash]C unsaturated carbon, C[double bond, length as m-dash]C, C–O, and O–H bonds, resulting in high mobility during column chromatography. Furthermore, the obtained G-NZVI showed the complete removal of 50 mg L−1 of bromate (BrO3−) in 2 min under both aerobic (k = 4.42 min−1) and anaerobic conditions (k = 4.50 min−1), showing that G-NZVI had outstanding oxidation resistance compared to that of bare NZVI. ..