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Biomedical subjects

H G Schmidt

Publications and source records attributed to H G Schmidt.

At least 19 recordsLinked to original sources
PubMed2006

Performance of academically at-risk medical students in a problem-based learning programme: a preliminary report.

INTRODUCTION: Racially segregated schooling, a legacy of Apartheid policies, continues to hamper education in South Africa. Students entering university from suboptimal circumstances are at significant risk of demonstrating poor academic performance and dropping out of their programmes. Attempts to address the educational needs of these students have included the introduction of extended medical programmes at several universities. Such a programme, the Academic Development Programme (ADP), was implemented at the University of Cape Town in 1991. Over the past decade the programme has graduated more than 100 students. Upon implementation of a new problem-based learning (PBL) programme in 2002, the ADP was discontinued and all students were entered directly into the new PBL programme. Students who demonstrate a need for additional academic support by the end of the first semester enter the Intervention Programme for 1 year before proceeding to the second semester of the PBL programme. An interim analysis was performed to compare the retention rates and academic performance of academically at-risk students in the new PBL programme and the ADP. METHODS: The records of all academically at-risk students entering the ADP (1991-2000) and the new PBL programme (2002) were reviewed. Retention rates for all years of study, and academic performance in the fourth year clerkship courses of the respective programmes were compared. RESULTS: A total of 239 academically at-risk students in the ADP and 43 at-risk students in the new PBL programme were studied. The median retention rates, per year of study, for at-risk students in the PBL programme was significantly better than for at-risk students in the ADP (p<0.02). Academic performance of the at-risk students in all the fourth year clinical clerkship courses of the PBL programme was significantly better than the mean performance over 10 years for at-risk students in the same fourth year courses in the ADP. CONCLUSION: The introduction of PBL at the University of Cape Town has not had a deleterious effect on the performance of academically at-risk medical students. Interim analysis suggests that retention rates and academic performance in the PBL programme are better than those achieved in the extended traditional programme.

Black People↗
PubMed2006

[Effects of problem-based medical education: 16 Dutch curriculum comparisons].

The effects of problem-based medical education on student performance were studied by curriculum comparison in 16 Dutch studies. The results suggest that students and graduates of the problem-based medical curriculum of Maastricht University in the Netherlands perform better on tests of diagnostic reasoning ability, in the area of interpersonal skills and in practical medical skills such as physical examination. No differences were found with respect to acquired medical knowledge. However, differential drop-out rates of students from the curricula compared may have masked the effects in this area.

Clinical Competence↗
PubMed2001

Facile synthesis of cyclopropene analogues of aluminum and an aluminum pinacolate, and the reactivity of LAl[eta(2)-C(2)(SiMe(3))(2)] toward unsaturated molecules (L=HC[(CMe)(NAr)](2), Ar=2,6-i-Pr(2)C(6)H(3)).

Reduction of LAlI(2) (1) (L = HC[(CMe)(NAr)](2), Ar = 2,6-i-Pr(2)C(6)H(3)) with potassium in the presence of alkynes C(2)(SiMe(3))(2), C(2)Ph(2), and C(2)Ph(SiMe(3)) yielded the first neutral cyclopropene analogues of aluminum LAl[eta(2)-C(2)(SiMe(3))(2)] (3), LAl(eta(2)-C(2)Ph(2)) (4), and LAl[eta(2)-C(2)Ph(SiMe(3))] (5), respectively, whereas reduction of 1 in the presence of Ph(2)CO gave an aluminum pinacolate LAl[O(2)(CPh(2))(2)] (6), irrespective of the amount of Ph(2)CO employed. The unsaturated molecules CO(2), Ph(2)CO, and PhCN inserted into one of the Al-C bonds of 3 leading to ring enlargement to give novel aluminum five-membered heterocyclic systems LAl[OC(O)C(2)(SiMe(3))(2)] (7), LAl[OC(Ph)(2)C(2)(SiMe(3))(2)] (8), and LAl[NC(Ph)C(2)(SiMe(3))(2)] (9) in high yields. In contrast, 3 reacted with t-BuCN, 2,6-Trip(2)C(6)H(3)N(3) (Trip = 2,4,6-i-Pr(3)C(6)H(2)), and Ph(3)SiN(3) resulting in the displacement of the alkyne moiety to afford LAl[N(2)(Ct-Bu)(2)] (10) with an unprecedented aluminum-containing imidazole ring, and the first monomeric aluminum imides LAlNC(6)H(3)-2,6-Trip(2) (11) and LAlNSiPh(3) (12). All compounds have been characterized spectroscopically. The variable-temperature (1)H NMR studies of 3 and ESR measurements of 3 and 4 suggest that the Al-C-C three-membered-ring systems can be best described as metallacyclopropenes. The (27)Al NMR resonances of 2 and 3 are reported and compared. Molecular structures of compounds 3, 4, 6.OEt(2), 8.OEt(2), and 9 were determined by single-crystal X-ray structural analysis.

Journal Article↗
PubMed2001

Halogenodisilanes: precursors for new disilane derivatives.

Starting from hexachloro- or hexabromodisilane a wide variety of 1,2-disubstituted tetrachlorodisilanes (RSiCl2SiCl2R) [R = Cp (2a), 4-iPrC6H4(SiMe3)N (2b), 2,6-iPr2C6H3(SiMe3)N (2c), (Me3Si)2CH (2d) (Me3Si)3C (2e), (Me3Si)3Si (2f)], tetrabromodisilanes (RSiBr2SiBr2R) [R = Cp (3a), 4-iPrC6H4(SiMe3)N (3b), (Me3Si)3Si (3f)] and the monosubstituted pentahalogenodisilanes CpSiX2SiX3 [X = Cl (4), Br (5)] were prepared. The tetrachlorodisilanes 2a-e are converted to various functionalized disilanes. Ammonolysis of 2a-e leads to the tetraaminodisilanes [RSi(NH2)2Si(NH2)2R] 6a-e. A reduction of 2d with LiAlH4 resulted in the formation of the disilane RSiH2SiH2R [R = (Me3Si)2CH] 7 and the metathesis with Me3SnF yielded the tetrafluorodisilane RSiF2SiF2R [R = (Me3Si)2CH] 8. Treatment of 6d with reagents containing H acidic protons (HX) [X = Br, I and OH] leads under elimination of NH3 to the tetrabromo- R2SiBr2SiBr2R (3d) tetraiodo- RSiI2SiI2R (9) and the tetrahydroxodisilane RSi(OH)2Si(OH)2R (10) [R = (Me3Si)2CH]. Single-crystal X-ray structural analysis of 2d, 6a, 6d, and 9 are reported.

Journal Article↗
PubMed2001

Synthesis and structural characterization of functionalized dimeric aluminophosphonates and a monomeric gallophosphonate anion.

Reaction of t-BuP(O)(OSiMe(3))(OH) with Me(3)Al leads to the formation of [Me(2)Al(mu-O)(2)P(OSiMe(3))(t-Bu)](2) (1) whereas Me(2)AlCl reacts with Ph(2)P(O)(OH) to yield [(Cl)(Me)Al(mu-O)(2)PPh(2)](2) (2). These compounds represent the first examples of functionalized dimeric four-ring type aluminophosphonate systems. The double four-ring type gallophosphonate, namely, [t-BuPO(3)GaMe](4), reacts with n-Bu(4)NHF(2) under ambient conditions, resulting in the formation of a monomeric gallophosphonate [n-Bu(4)N][MeGa[t-BuPO(2)(OH)](3)] (3). These derivatives have been adequately characterized using various spectroscopic techniques and X-ray diffraction studies.

Journal Article↗
PubMed2001

Syntheses and characterization of mu,eta(1),eta(1)-3,5-di-tert-butylpyrazolato derivatives of aluminum.

The 3,5-di-tert-butylpyrazolato (3,5-tBu(2)pz) derivatives of aluminum [(eta(1),eta(1)-3,5-tBu(2)pz)(mu-Al)R(1)R(2)](2) (R(1) = R(2) = Me 1; R(1) = R(2) = Et, 2; R(1) = R(2) = Cl, 3; R(1) = R(2) = I, 4; [(eta(2)-3,5-tBu(2)pz)(3)Al], 5; [Al(2)(eta(1),eta(1)-3,5-tBu(2)pz)(2)(mu-E)(C triple bond CPh)(2)] (E = S (6), Se (7), Te (8)) have been prepared in good yield. Compounds 1 and 2 were obtained by the reactions of H[3,5-tBu(2)pz] with Me(3)Al and Et(3)Al, respectively. Reaction of [(eta(1),eta(1)-3,5-tBu(2)pz)(mu-Al)H(2)](2) with the pyrazole H[3,5-tBu(2)pz] gave [(eta(2)-3,5-tBu(2)pz)(3)Al] (5). The reaction of [(eta(1),eta(1)-3,5-tBu(2)pz)(mu-Al)R(2)](2) (R = H, Me) and I(2) yielded 4, while the reaction of 1 equiv of K[3,5-tBu(2)pz] and AlCl(3) afforded 3. In addition, the reaction of [Al(2)(eta(1),eta(1)-3,5-tBu(2)pz)(2)(mu-E)H(2)] and HC triple bond CPh gave 6, 7, and 8. All compounds have been characterized by elemental analysis, NMR, and mass spectroscopy. The molecular structure analyses of compounds 1, 3, 6, and 7 by X-ray crystallography showed that complexes 1 and 3 are dimeric with two eta(1),eta(1)-pyrazolato groups in twisted conformation while 6 and 7 with two eta(1),eta(1)-pyrazolato groups display a boat conformation.

Journal Article↗
PubMed2001

Self-reported competency ratings of graduates of a problem-based medical curriculum.

PURPOSE: To study the self-reports of professional competencies by graduates of a problem-based medical curriculum. METHOD: All graduates from a medical school and a faculty of health sciences with a problem-based curriculum were sent a questionnaire asking them to compare their own performances in 19 domains with those of colleagues trained at schools with conventional curricula. RESULTS: Overall, alumni of the medical school rated themselves as better than colleagues who were trained at schools with conventional curricula for cooperation skills, problem-solving skills, skills relevant to running meetings, and the ability to work independently. There was no difference for possession of general academic knowledge and writing reports or articles. The self-reported ratings of better competencies were maintained after correcting the data for self-overestimation. CONCLUSION: The problem-based medical curriculum appears to contribute to the development of professional competencies. Further study is needed, however, to control for the effect of selection bias and respondents' emotional commitment to their alma mater.

Attitude of Health Personnel↗
PubMed2000

Application of n-Bu4NHF2 as a fluorinating agent for the preparation of fluoroanions: synthesis and crystal structure of the anions [t-BuPO3AlF2]2(2-), [PhPO3AlF2]2(2-), and [(O-i-Pr)3Ti(mu-F)2(mu-O-i-Pr)Ti(O-i-Pr)3]-.

The first phosphonate anions of aluminum-containing fluorine and an anionic bridged fluoroalkoxy derivative of titanium have been realized using n-Bu4NHF2 as a fluorinating agent in organometallic synthesis. Reactions of [RPO3AlMe]4 [R = Ph (1), t-Bu] with n-Bu4NHF2 yield organic-soluble compounds of the type [n-Bu4N]2[RPO3AlF2]2 [R = Ph (2), t-Bu (3)], whereas the reaction of Ti(O-i-Pr)4 with n-Bu4NHF2 results in the formation of [n-Bu4N][O-i-Pr)3Ti(mu-F)2(mu-O-i-Pr)Ti(O-i-Pr)3] (4). These compounds have been obtained in high yields and have been adequately characterized through spectroscopic techniques and X-ray diffraction studies.

Journal Article↗
PubMed2000

Metal alkoxides as versatile precursors for group 4 phosphonates: synthesis and X-ray structure of a novel organosoluble zirconium phosphonate.

Reactions of Ph2P(O)(OH) and t-BuP(O)(OSiMe3)(OH) with Ti(O-i-Pr)4 in equimolar ratios gave titanium phosphonates of the type [(O-i-Pr)3Ti(mu-O)2PR1R2]2 (1, R1 = R2 = Ph; 2, R1 = t-Bu, R2 = OSiMe3) as colorless crystalline solids in moderate yields. Reactions of Ph2P(O)(OH) and the isopropoxides of zirconium and hafnium resulted in products of the composition [(O-i-Pr)3M(mu-O-i-Pr)2(mu-OPOPh2)M(O-i-Pr)2]Ph2P(O)(OH) (M = Zr (3), Hf (4)) in high yields. The compounds were characterized by 1H, 31P, and 29Si NMR, infrared (IR), and mass spectroscopic (MS) techniques. The molecular structures of 2 and 3 were confirmed by X-ray crystallography.

Journal Article↗
PubMed2000

Effectiveness of problem-based learning curricula: theory, practice and paper darts.

In a recent review article, Colliver concluded that there was no convincing evidence that problem-based learning was more effective than conventional methods. He then went on to lay part of the blame on cognitive psychology, claiming that 'the theory is weak, its theoretical concepts are imprecise. the basic research is contrived and ad hoc'. This paper challenges these claims and presents evidence that (a) cognitive research is not contrived and irrelevant, (b) curriculum level interventions are doomed to fail and (c) education needs more theory-based research.

Clinical Competence↗
PubMed2000

Remembering the street names of one's childhood neighbourhood: a study of very long-term retention.

Life-span retention of street names was studied in a sample of former students of a Dutch elementary school. Participants were requested to recall the street names of their childhood neighbourhood and indicate their position on a map. In addition, information was gathered concerning (a) the extensiveness of the original learning experience, (b) its elaborateness, and (c) the amount of interference from similar materials occurring between original learning experience and time of recall. Retention intervals varied from 0 to 71 years. Amount of exposure, elaborateness of learning, and retroactive interference all contributed to the memorability of names. In addition, the forgetting curve showed a permastore effect (Bahrick, 1984), suggesting that memory for non-schematic, incidentally learned material is subject to processes of forgetting similar to those that affect intentionally learned material, such as subject-matter acquired in school.

Adolescent↗
PubMed2000

A taxonomy of community-based medical education.

The authors propose a classification of community-based education (CBE) as it is implemented all over the world. To create this taxonomy, they used reports in the literature of 31 active programs in many locations. A CBE program is an instructional program carried out in a community context, outside the academic hospital. The authors distinguish between programs that are developed primarily to provide services to an underserved community; programs that have a research focus; and programs that have as their primary goal the (clinical) training of students. These three major types can be subdivided in six minor types, among them community development programs, health intervention programs, and simple community-exposure programs. The ultimate goal of creating the taxonomy is to contribute to the development of a theory of CBE and provide a more systematic way to study CBE. In addition, the proposed taxonomy clearly demonstrates the various ways in which medical schools, their staffs, and their students can become involved with the communities served. CBE is not a unitary concept but a set of attempts to contribute to the quality of life in a particular community and, at the same time, create conditions for students to acquire hands-on understanding of the nature of the problems to be faced in future professional practice, and to develop relevant skills. The taxonomy also enables those involved in the development of CBE programs in their medical schools to see alternative approaches, which will help them choose the approaches that fit their particular educational goals. Last, it demonstrates the intricacies involved in the implementation of CBE, in particular the complexity of building a learning environment that is productive for students and, at the same time, responsive to community needs.

Community Medicine↗
PubMed1998

Student assessment in community settings: a comprehensive approach.

Student assessment in community settings presents problems for medical teachers, e.g., difficulties in assessing the contribution of individual members to group work, and lack of test standardization due to varying field conditions. The Faculty of Medicine, University of Gezira, Sudan is a community-oriented, community-based medical school which has adopted a comprehensive approach to student assessment in community settings using various methods, including peer assessment, a supervisory checklist, community feedback, reports from students, short essay questions (SEQs) and multiple choice questions (MCQs). Each method focuses on a specific aspect of the objectives of the community-based programme and is weighted in the final grade according to the extent to which objectives were covered. This assessment programme contrasts with the conventional teacher-centred approach, and is continuously monitored and improved using a variety of sources of information. A total of 105 students participated in a study designed to measure the reliability and validity of this approach. The reliability of the methods was tested by computing the alpha coefficient and was found to range between 0.77 and 0.92. This was considered acceptable. The validity of the instruments was examined using confirmatory factor analysis, and their content validity was reviewed. The results show that the comprehensive approach used is fairly valid. It is suggested that the University's approach is successful in solving some of the problems of student assessment in community settings.

Clinical Competence↗