Lost in translation: Unveiling medical students' untold errors of medical history documentation

OBJECTIVE

The accurate documentation of a medical history interview is an important goal in medical education. As students' documentation of medical history interviews is mostly decentralised on the wards, a systematic assessment of documentation quality is missing. We therefore evaluated the extent of details missed in students' medical history reports in a standardised setting.

METHODS

In this prospective, observational study, 123 of 380 students (32.4%) participated in an Objective Structured Clinical Examination (OSCE) regarding history taking and documentation. Based on the interviews and nine deductively selected main categories, a categorical system was established using a summarising qualitative content analysis. The items in the transcripts (defined as ground truth) and in students' reports were labelled and assigned to the correct subcategory. The ground truth and students' reports were compared to quantify students' documentation completeness.

RESULTS

Next to the nine deductively selected main categories, 61 subcategories were defined. A total of 8943 items were labelled in the 123 interview transcripts (ground truth), compared with 5870 items labelled in students' reports (65.6% completeness of students' reports compared with ground truth). The main category personal details overlapped with 94.2% between students' report and ground truth in contrast to the main category with the highest discrepancy, allergy, with 41.1% overlap. Pertinent negative items and non-numerical quantifications were often missed.

CONCLUSIONS

Medical students show incomplete documentation of medical history interviews. Therefore, accurate documentation should be taught as an important goal in medical education.

How do parents perceive their children's epileptic seizures? Experiences of the first seizure and changes during the course of the epilepsy

PROBLEM

Experiencing a child's seizure can be challenging for parents.

METHODS

We investigated parental experiences of their child's first seizure and how their perception and management of seizures changed over time. From September 2020 to March 2021, we invited parents who had witnessed at least two of their child's seizures to take part in a semi-structured interview. Parents whose children experienced solely absence seizures were excluded.

RESULTS

Of the parents, 52/74 (70%) did not recognize their child's first epileptic seizure and assumed the event to be due to a different cause, for instance teething. Parents overwhelmingly reported fear (48/74; 65%) and surprise (13/74; 18%) as the predominant emotional responses to the first seizure. In response to the most recently observed seizure parents reported feelings related to fear (33/74; 45%) and happiness (16/74; 22%), with regard to the latter, especially "being calm" or "feeling safe". Asked for thoughts in response to the first seizure, 22/74 (30%) reported concerns about their child's future, with regard to the most recent seizure, 15/74 (20%) expressed such thoughts. Of the parents, 53/74 (72%) did not know how to respond to the first seizure. Concerning the most recent seizure, 48/74 (65%) said they felt confident in managing the seizure.

CONCLUSION

Experiencing the child's first seizure was very challenging for parents. During the course of the epilepsy, changes were observed in both parental perception of and confidence in managing the seizures. Physicians should consider these changes when counselling parents in order to better target their evolving needs.

Early clinical trial unit tumor board: a real-world experience in a national cancer network

PURPOSE

Early clinical trials are the first step into clinical therapies for new drugs. Within the six Bavarian university-based hospitals (Augsburg, Erlangen, Regensburg, Munich (LMU and TU), Würzburg) we have enrolled a virtual network platform for patient discussion.

METHODS

The virtual Early Clinical Trial Unit Tumor Board (ECTU Tumor Board) is a secured web-based meeting to evaluate early clinical trial options for patients, where representatives from local ECTUs participate. We retrospectively analyzed patient cases discussed between November 2021 and November 2022.

RESULTS

From November 2021 to November 2022, a total of 43 patients were discussed in the ECTU Tumor Board. Median age at diagnosis was 44.6 years (range 10-76 years). The median number of previous lines of therapies was 3.7 (range 1-9 therapies) including systemic treatment, surgery, and radiation therapy. A total of 27 different tumor entities were presented and 83.7% (36/43) patients received at least one trial recommendation. In total, 21 different active or shortly recruiting clinical trials were recommended: ten antibody trials, four BiTE (bispecific T cell engager) trials, six CAR (chimeric antigen receptor) T-cell trials, and one chemotherapy trial. Only six trials (28.6%) were recommended on the basis of the previously performed comprehensive genetic profiling (CGP).

CONCLUSION

The ECTU Tumor Board is a feasible and successful network, highlighting the force of virtual patient discussions for improving patient care as well as trial recruitment in advanced diseases. It can provide further treatment options after local MTB presentation, aiming to close the gap to access clinical trials.

The PERCIVAL detector: first user experiments

The PERCIVAL detector is a CMOS imager designed for the soft X-ray regime at photon sources. Although still in its final development phase, it has recently seen its first user experiments: ptychography at a free-electron laser, holographic imaging at a storage ring and preliminary tests on X-ray photon correlation spectroscopy. The detector performed remarkably well in terms of spatial resolution achievable in the sample plane, owing to its small pixel size, large active area and very large dynamic range; but also in terms of its frame rate, which is significantly faster than traditional CCDs. In particular, it is the combination of these features which makes PERCIVAL an attractive option for soft X-ray science.

Online medical history taking course: Opportunities and limitations in comparison to traditional bedside teaching

OBJECTIVE

Obtaining a systematic medical history (MH) from a patient is a core competency in medical education and plays a vital role in the diagnosis of diseases. At the Faculty of Medicine at LMU Munich, students have their first course in MH taking during their second year. Due to the COVID-19 pandemic, the traditional bedside MH taking course had to be transformed into an online course (OC). Our objectives were to implement an online MH taking course, to evaluate its feasibility and to compare the evaluation results to a historic cohort that had undertaken the traditional bedside teaching course (BTC).

METHODS

874 second-year students participated in the OC (BTC=827). After teaching the theoretical background via asynchronous online lectures, students participated in a practical exercise with fellow students using the video communication platform Zoom where they were able to practice taking a MH on the basis of fictitious, text-based patient cases. Students were then asked to evaluate the course through a standardized online survey with 31 questions on teaching quality and self-perceived learning success, which had also been used in previous years. The survey results were compared to the results of the historic cohort using the Mann-Whitney U test.

RESULTS

A total of n=162 students (18.5%) evaluated the OC. In the historic cohort, n=252 (30.5%) completed the survey. 85.3% of the OC respondents thought that the atmosphere during the practical exercise was productive and 83.0% greatly appreciated the flexibility in terms of time management. Moreover, they appreciated the online resources as well as having the opportunity to undertake a MH taking course during the COVID-19 pandemic. 27.7% of the respondents thought that traditional BTCs should be supplemented through more online activities in the future. With respect to the ability of independently taking a MH upon completion of the course, the OC was rated significantly lower relative to the BTC (mean OC=2.4, SD=±1.1 vs. mean BTC=1.9, SD=±1.1 (1=strongly agree; 5=strongly disagree); p<0.0001).

CONCLUSION

OCs are a feasible format and seem to convey the theory and practical implementation in a peer-exercise format of MH taking to medical students. The theoretical background can be acquired with great flexibility. Nevertheless, the students' self-appraisal suggested that the traditional teaching format was more effective at teaching MH taking skills. Thus, we propose a blended learning concept, combining elements of both formats. In this context, we suggest prospective, randomized trials to evaluate blended learning approaches.

Cambridge hybrid closed-loop algorithm in children and adolescents with type 1 diabetes: a multicentre 6-month randomised controlled trial

BACKGROUND

Closed-loop insulin delivery systems have the potential to address suboptimal glucose control in children and adolescents with type 1 diabetes. We compared safety and efficacy of the Cambridge hybrid closed-loop algorithm with usual care over 6 months in this population.

METHODS

In a multicentre, multinational, parallel randomised controlled trial, participants aged 6-18 years using insulin pump therapy were recruited at seven UK and five US paediatric diabetes centres. Key inclusion criteria were diagnosis of type 1 diabetes for at least 12 months, insulin pump therapy for at least 3 months, and screening HbA1c levels between 53 and 86 mmol/mol (7·0-10·0%). Using block randomisation and central randomisation software, we randomly assigned participants to either closed-loop insulin delivery (closed-loop group) or to usual care with insulin pump therapy (control group) for 6 months. Randomisation was stratified at each centre by local baseline HbA1c. The Cambridge closed-loop algorithm running on a smartphone was used with either (1) a modified Medtronic 640G pump, Medtronic Guardian 3 sensor, and Medtronic prototype phone enclosure (FlorenceM configuration), or (2) a Sooil Dana RS pump and Dexcom G6 sensor (CamAPS FX configuration). The primary endpoint was change in HbA1c at 6 months combining data from both configurations. The primary analysis was done in all randomised patients (intention to treat). Trial registration ClinicalTrials.gov, NCT02925299.

FINDINGS

Of 147 people initially screened, 133 participants (mean age 13·0 years [SD 2·8]; 57% female, 43% male) were randomly assigned to either the closed-loop group (n=65) or the control group (n=68). Mean baseline HbA1c was 8·2% (SD 0·7) in the closed-loop group and 8·3% (0·7) in the control group. At 6 months, HbA1c was lower in the closed-loop group than in the control group (between-group difference -3·5 mmol/mol (95% CI -6·5 to -0·5 [-0·32 percentage points, -0·59 to -0·04]; p=0·023). Closed-loop usage was low with FlorenceM due to failing phone enclosures (median 40% [IQR 26-53]), but consistently high with CamAPS FX (93% [88-96]), impacting efficacy. A total of 155 adverse events occurred after randomisation (67 in the closed-loop group, 88 in the control group), including seven severe hypoglycaemia events (four in the closed-loop group, three in the control group), two diabetic ketoacidosis events (both in the closed-loop group), and two non-treatment-related serious adverse events. There were 23 reportable hyperglycaemia events (11 in the closed-loop group, 12 in the control group), which did not meet criteria for diabetic ketoacidosis.

INTERPRETATION

The Cambridge hybrid closed-loop algorithm had an acceptable safety profile, and improved glycaemic control in children and adolescents with type 1 diabetes. To ensure optimal efficacy of the closed-loop system, usage needs to be consistently high, as demonstrated with CamAPS FX.

FUNDING

National Institute of Diabetes and Digestive and Kidney Diseases.

Erratum: Azimuthal Anisotropy of K_{S}^{0} and Λ+Λ[over ¯] Production at Midrapidity from Au+Au Collisions at sqrt[s]_{NN}=130 GeV [Phys. Rev. Lett. 89, 132301 (2002)]

This corrects the article DOI: 10.1103/PhysRevLett.89.132301.

Erratum: Azimuthal Anisotropy at the Relativistic Heavy Ion Collider: The First and Fourth Harmonics [Phys. Rev. Lett. 92, 062301 (2004)]

This corrects the article DOI: 10.1103/PhysRevLett.92.062301.

Association between ideal cardiovascular health and depression incidence: a longitudinal analysis of ELSA-Brasil

OBJECTIVE

We investigated whether ideal cardiovascular health (ICH), a metric proposed by the American Heart Association, predicts depression development.

METHODS

Cohort analysis from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Adults with no current depression and other common mental disorders, cardiovascular diseases, and antidepressant drug use at baseline had their ICH (composite score of smoking, dietary habits, body mass index, blood pressure, fasting glucose, cholesterol, and physical activity) assessed and classified into poor, intermediate, and optimal. Depression was assessed using the Clinical Interview Schedule-Revised (CIS-R). Poisson regression models, adjusted for sociodemographic factors and alcohol consumption, were employed. Stratified analyses were performed for age and sex.

RESULTS

We included 9214 participants (mean age 52 ± 9 years, 48.6% women). Overall depression incidence at 3.8-year follow-up was 1.5%. Intermediate and poor ICH significantly increased the risk rate (RR) of developing depression (2.48 [95%CI 1.06-5.78] and 3 [1.28-7.03], respectively) at a 3.8-year follow-up. Higher ICH scores decreased the rate of depression development (RR = 0.84 [0.73-0.96] per metric). Stratified analyses were significant for women and adults < 55 years old.

CONCLUSIONS

Poor cardiovascular health tripled depression risk at follow-up in otherwise healthy adults. Ameliorating cardiovascular health might decrease depression risk development.

Anti-Inflammatory Substances in Wheat Malt Inducing Antisecretory Factor

Extensively malted cereals counteract enterotoxic diarrhea and inflammatory bowel diseases. This effect depends on a protein called antisecretory factor (AF), which is secreted into the blood as a larger complex known as the compleasome. In this study, we identified anti-inflammatory substances in malt and assayed their capacity to induce AF. Guaiacol and quercetin inhibited inflammation in a mouse footpad model, while catechin, sinapic acid, ferulic acid, and quercetin inhibited nitric oxide formation in RAW 264.7 cells. The proteasome activity in these cells was inhibited by vanillic acid and quercetin but not by the other tested phenols. As the transient receptor potential vanilloid 1 (TRPV1) might be involved in AF induction, the TRPV1 antagonist capsazepine was tested and shown to inhibit inflammation in mouse paw and nitric oxide formation. Catechin, ferulic acid, and sinapic acid induced AF in rat blood, and these substances were all increased in malt compared to control wheat. These phenols might therefore be of particular importance for the beneficial effect of malted cereals on inflammatory diseases. Our results further suggest that TRPV1 might play a role in the anti-inflammatory activity of phenols via the induction of AF.

Charakterisierung von Faktor-VIII-Antikörperepitopen mit Faktor-VIII-Peptid-Bibliotheken

Etwa 30% der Patienten die an schwerer Hämophilie A leiden, entwickeln als Komplikation einer Substitutionstherapie gegen Faktor VIII gerichtete Antikörper, die die prokoagulatorische Aktivität von intravenös injizierten FVIII-Proteinen neutralisieren. In der Regel werden verschiedene Epitope auf dem FVIII-Molekül durch diese Antikörper gebunden. Die detaillierte Struktur dieser Epitope ist unbekannt. In dieser Studie werden Epitope auf dem Faktor-VIII-Molekül mit Hilfe festphasengebundener Peptid-Arrays identifiziert, auf denen die Aminosäuresequenz des FVIII in Oligopeptiden dargestellt wird. Die Bindung von FVIII-Antikörpern an bestimmte Peptidsequenzen zeigt potenzielle Epitopstrukturen. FVIII-Antikörper von Inhibitorpatienten und gesunden Blutspendern werden zurzeit mit dieser Methode charakterisiert. Identifizierte Epitope können zur Entwicklung neuer Therapiekonzepte führen, die dazu dienen, eine Hemmkörperentwicklung zu vermeiden bzw. bereits entstandene Hemmkörper besser zu eliminieren. Als Teilprojekt des Konsortiums »Hämophilie A« wird im Rahmen des Gesamtvorhabens »Genotyp-Phänotyp-Korrelation bei der Hämophilie A« untersucht, ob die Epitopcharakteristik mit dem Typ und der Position der FVIII-Genmutationen korreliert sowie Zusammenhänge zwischen Epitop und klinischem Verlauf der Krankheit bestehen. Zusätzlich wird der Einfluss der Epitope auf den therapeutischem Effekt und Erfolg der Immuntoleranzinduktion untersucht.

Exercise-induced alterations and loss of sarcomeric M-line organization in the diaphragm muscle of obscurin knockout mice

We recently reported that skeletal muscle fibers of obscurin knockout (KO) mice present altered distribution of ankyrin B (ankB), disorganization of the subsarcolemmal microtubules, and reduced localization of dystrophin at costameres. In addition, these mice have impaired running endurance and increased exercise-induced sarcolemmal damage compared with wild-type animals. Here, we report results from a combined approach of physiological, morphological, and structural studies in which we further characterize the skeletal muscles of obscurin KO mice. A detailed examination of exercise performance, using different running protocols, revealed that the reduced endurance of obscurin KO animals on the treadmill depends on exercise intensity and age. Indeed, a mild running protocol did not evidence significant differences between control and obscurin KO mice, whereas comparison of running abilities of 2-, 6-, and 11-mo-old mice exercised at exhaustion revealed a progressive age-dependent reduction of the exercise tolerance in KO mice. Histological analysis indicated that heavy exercise induced leukocyte infiltration, fibrotic connective tissue deposition, and hypercontractures in the diaphragm of KO mice. On the same line, electron microscopy revealed that, in the diaphragm of exercised obscurin KO mice, but not in the hindlimb muscles, both M-line and H-zone of sarcomeres appeared wavy and less defined. Altogether, these results suggest that obscurin is required for the maintenance of morphological and ultrastructural integrity of skeletal muscle fibers against damage induced by intense mechanical stress and point to the diaphragm as the skeletal muscle most severely affected in obscurin-deficient mice.

Selective catalytic hydrogenation of nitriles to primary amines using iron pincer complexes

The selective catalytic hydrogenation of nitriles to primary amines with the well-defined Fe(PNP^Cy) pincer complex 2 is reported.

Alcohol use and self-perceived mental health status among pregnant and breastfeeding women in Canada: a secondary data analysis

OBJECTIVE

To estimate the prevalence of alcohol consumption during pregnancy and while breastfeeding in Canada from 2003 to 2010, and to test the relation between self-perceived mental health status and alcohol consumption during pregnancy and while breastfeeding.

DESIGN

Secondary analysis of four cycles of the Canadian Community Health Survey, a population-based cross-sectional survey.

SETTING

Canada.

SAMPLE

A total of 18 612 pregnant and 15 836 breastfeeding women.

METHODS

The prevalence of alcohol consumption during pregnancy and while breastfeeding and 95% confidence intervals (CI) were calculated by province and territory, and cycle. The relation between self-perceived mental health status and alcohol consumption during pregnancy and while breastfeeding was explored using quasi-Poisson regression models.

MAIN OUTCOME MEASURES

Alcohol consumption during pregnancy and while breastfeeding, and self-perceived mental health status.

RESULTS

In Canada, between 2003 and 2010, approximately one in every ten pregnant women (9.9%; 95%CI 9.2-10.5%) and two in every ten breastfeeding women (20.3%; 95%CI 19.4-21.2%) women consumed alcohol. Women with a lower self-perceived mental health status (i.e. 'good') were 1.40 (95%CI 1.18-1.67, P < 0.001) times more likely to have consumed alcohol during pregnancy, compared with women with an 'excellent' self-perceived mental health. There were no notable differences between the categories of mental health status in regard to alcohol consumption while breastfeeding.

CONCLUSION

Despite public health efforts in Canada, a significant proportion of pregnant and breastfeeding women consume alcohol. It is imperative that a standard screening protocol be initiated among pregnant and breastfeeding women, especially in high-risk populations (e.g. women utilising substance abuse treatment programs).

TWEETABLE ABSTRACT

In Canada in 2003-2010, approximately 10% of pregnant and 20% of breastfeeding women consumed alcohol.

Local and Systemic Therapies for Breast Cancer Patients: Reducing Short-term Symptoms with the Methods of Integrative Medicine

With improved prognosis due to advances in the diagnosis and therapy of breast cancer, physicians and therapists now focus on aspects such as quality of life and the management of side effects from breast cancer treatment. Therapy- and disease-related side effects often reduce the patient's quality of life and can place a further burden on patients, with non-compliance or discontinuation of therapy a potential consequence. Study data have shown that therapy- and disease-related side effects can be reduced using the methods of integrative medicine. Reported benefits include improving patients' wellbeing and quality of life, reducing stress, and improving patients' mood, sleeping patterns and capacity to cope with disease. Examining the impact of integrative medicine on the side effects of cancer treatment would be beyond the scope of this review. This article therefore looks at short-term side effects of cancer treatment which are usually temporary and occur during or after local and systemic therapy. The focus is on mind-body medicine, acupuncture and classic naturopathic treatments developed by Sebastian Kneipp as complementary therapies. The latter includes hydrotherapy, phytotherapy, nutritional therapy, exercise therapy and a balanced lifestyle.

Global structure of regular tori in a generic 4D symplectic map

For the case of generic 4d symplectic maps with a mixed phase space, we investigate the global organization of regular tori. For this, we compute elliptic 1-tori of two coupled standard maps and display them in a 3d phase-space slice. This visualizes how all regular 2-tori are organized around a skeleton of elliptic 1-tori in the 4d phase space. The 1-tori occur in two types of one-parameter families: (α) Lyapunov families emanating from elliptic-elliptic periodic orbits, which are observed to exist even far away from them and beyond major resonance gaps, and (β) families originating from rank-1 resonances. At resonance gaps of both types of families either (i) periodic orbits exist, similar to the Poincaré-Birkhoff theorem for 2d maps, or (ii) the family may form large bends. In combination, these results allow for describing the hierarchical structure of regular tori in the 4d phase space analogously to the islands-around-islands hierarchy in 2d maps.

[Antibiotic Consumption and the Development of Antibiotic Resistance in Surgical Units]

BACKGROUND

Antibiotic resistence is increasing worldwide.

AIM

A longitudinal analysis of the influence of the density of antibiotic use on the development of resistance in surgical units was undertaken.

MATERIAL AND METHODS

Over five years the incidence of pathogens and the resistance rates of isolates from patients of normal surgical units and those of a surgical ICU at a university hospital were examined. The resistence rates were correlated with the density of antibiotic use - calculated from the antibiotic consumption (in DDD) and the number of patient-days.

RESULTS

At both units, Enterobacteriaceae and Enterococci were mostly cultured. Among the Enterobacteriaceae, E. coli, Klebsiella spp., Proteus mirabilis and Enterobacter predominated. In the group of Enterococci, E. faecalis predominated at wards whereas at ICU E. faecium was the most frequent. Anaerobes ranked third at normal wards and Candida spp. at ICU. From 2007 to 2011, there was an increasing resistance against ciprofloxacin in P. mirabilis (r = 0.87; p = 0.054) and against imipenem (r = 0.86; p = 0.06) and piperacillin (r = 0.81; p = 0.09) in P. aeruginosa at normal wards. At ICU, the resistance rates of imipenem in P. aeruginosa rose (r = 0.88; p = 0.049). Resistance against ciprofloxacin in E. coli increased (r = 0.65; p = 0.23). Due to the increasing use of ciprofloxacin and meropenem at normal wards, the density of antibiotic usage rose 1.4 %/year (r = 0.94; p = 0.02). Despite the increase of meropenem use at ICU (r = 0.9; p = 0.035), the total antibiotic uptake rate remained almost constant. The antibiotic usage density was 3-fold higher at ICU than at normal wards. At normal wards, the ciprofloxacin usage correlated with the rate of resistance against ciprofloxacin in P. mirabilis P. m. At ICU, an association was detected between the uptake rate of ceftazidime and the rate of resistance against cefotaxime in the CES group. In P. aeruginosa, the use of piperacillin and the rate of resistance against piperacillin correlated.

CONCLUSION

The high uptake rates of fluoroquinolones and carbapenems were accompanied by increases in resistances. The resistance rates are influenced by hygiene management and microbiological diagnostics. The extensive use of carbapenems should be reassessed on both units to counter further development of antibiotic resistance.

Expression and prognostic significance of hsa-miR-142-3p in acute leukemias

OBJECTIVES

The microRNA 142 (miR-142) is expressed at high levels in mature hematopoietic cells and has a crucial role during T-lymphocyte development. Its role in leukemogenesis is unclear.

PATIENTS AND METHODS

Expression of miR-142 was analyzed in acute myeloid and lymphoblastic leukemia cells (de novo, cell lines). Data were compared to expression in CD34+ hematopoietic cells. Based on the miR-142 expression, clinical data such as overall survival was analyzed.

RESULTS

MiR-142 expression in all leukemia cell lines and 86 % of the de novo samples was higher than in CD34+ cells. This difference could be detected in both, myeloid and lymphoid neoplastic cells. In AML patients with intermediate cytogenetic risk a high miR-142 expression was associated with a better overall survival.

CONCLUSIONS

MiR-142 expression in acute lymphoblastic as well as myeloid leukemia cells is higher than in CD34+ cells. Additionally, miR-142 expression might have prognostic relevance in AML-patients with otherwise an intermediate cytogenetic risk.

Recombinant Production of Horseradish Peroxidase Conjugates with Fab Antibodies in Pichia pastoris for Analytical Applications

Recombinant immunoconjugates of marker enzymes with antigens or antibodies present considerably more advantages than those obtained by conventional methods of chemical synthesis; i.e. they are homogeneous, have a strictly determined stoichiometry, and retain the functional activity of both a marker protein and an antigen/antibody. Based on the pPICZαB shuttle vector, we first managed to obtain a recombinant conjugate of key marker enzyme horseradish peroxidase (HRP) withFabfragments of antibodies against atrazine. The resulting genetic construction allows us to switch to any other antibody sequence, via the simple re-cloning of variable parts and an additional reporter enzyme. Conjugates were successfully produced in thePichia pastorismethylotrophic yeast expression system. The target activity of the conjugates (both enzymatic and antigen-binding) has been demonstrated by ELISA method.

Influence of brain tumors on the MR spectra of healthy brain tissue

The neurochemical environment of nontumorous white matter tissue was investigated in 135 single voxel spectra of "healthy" white matter regions of 43 tumor patients and 129 spectra of 52 healthy subjects. Spectra were acquired with short TE and TR values. With the data of tumor patients, it was examined whether differences were caused by the tumor itself or aggressive tumor therapies as confounding factors. Comparing the spectra of both classes, an excellent differentiation was possible based on the metabolite peak of N-acetylaspartate (P ≈ 0) and myoinositol (P < 0.03). The area under curve of the receiver operating characteristic was calculated as 0.86 and 0.62, respectively. With linear discriminant analysis using combinations of integrals, a prediction was possible, whether a spectrum belonged to the patient or the healthy subject class with an overall accuracy above 80%. The confounding factors could be ruled out as source of the differences. The results show strong evidence for an influence of malignant growth on the biochemical environment of nontumorous white matter tissue. Because of the T(1) weighting, the measured differences between both classes were most likely concentration changes interfered by T(1) effects. The underlying processes will be subject of future studies.

A luminescence spectroscopy and theoretical study of 4f-5d transitions of Ce3+ ions in SrAlF5 crystals

This research is focused on the 4f-5d transitions in Ce(3+) centers doped into tetragonal β-SrAlF(5) single crystals belonging to the I4(1)/a space group. The presence of four non-equivalent Sr(2+) sites in this compound leads to the appearance of three spectroscopically non-equivalent Ce(3+) luminescence centers, which can be well distinguished using a time-resolved laser spectroscopy technique. All 4f-5d transitions have slightly varying excitation and emission energies with characteristic probabilities resulting in several decay times that can be determined experimentally. One of these centers experiences strong perturbation due to a defect nearby, probably the O(2-) impurity ion substituting for the F(-) ion and acting as a charge compensator as well. Identification of these photoluminescence centers is performed using crystal field calculations. The crystal field parameters are calculated for two identified centers using the structural data for SrAlF(5); diagonalization of the crystal field Hamiltonian results in obtaining the splitting of the Ce(3+) 5d states. This method allows 'regular' unperturbed Ce(3+) centers with selected Sr(2+) sites to be assigned.

Disorder effects in pnictides: a tunneling spectroscopy study

We present the synthesis and the tunneling spectroscopy study of superconducting FeSe(0.5)Te(0.5) (T(c) = 14 K), SmFeAsO(0.85) (T(c) = 54 K) and SmFeAsO(0.9)F(0.1) (T(c) = 45 K). The samples were characterized by Rietveld refinement of x-ray diffraction patterns and transport as well as temperature-dependent magnetic measurements. Tunneling experiments on FeSe(0.5)Te(0.5) revealed a single superconducting gap ∼ 1 meV in BCS-like tunneling conductance spectra. In SmFeAsO(0.85) and SmFeAsO(0.9)F(0.1), however, more complex spectra were observed, characterized by two gap-like structures at ∼ 4 and ∼ 10 meV. These spectra are qualitatively understood assuming a two-band superconductor with a 's ±' order parameter. We show that, depending on the sign relation between the pairing amplitudes in the two bands, the interband quasiparticle scattering has a crucial effect on the shape of the tunneling spectra. On the other hand, single-gap spectra found in FeSe(0.5)Te(0.5) are more compatible with a disorder-induced 's '-wave gap, due to the Se-Te substitution.

Silver(I)-(poly)chalcogenide Halides – Ion and Electron High Potentials

Materials with high dynamics in the solid state are of potential interest in semiconductor science and for a great variety of energy applications. In most of the cases the majority of physical properties of such compounds are directly related to their electronic structure. Optimization of properties is therefore correlated with direct or indirect control of this parameter. Compounds with highly mobile ions like the coinage metal cations and the heavy chalcogenide anions can easily be modified chemically or physically to fine tune their electronic structures. The range of adjustable properties lasts from ion conductivity, magneto resistance, thermoelectricity to a reversible redox-driven switch of semiconductivity. Today, the strong demand on clean energy production, the efficient energy transport and energy storage is a major goal for present and oncoming generations. Stable, mixed-conducting materials will play a major role in this process. The ongoing development of coinage metal chalcogenide halides during the last 50 years reflects the fundamental interest in this field. Many interesting and sometimes unexpected properties have been determined recently which substantiates the great potential of this class of materials. Especially the new class of coinage metal polychalcogenide halides is of potential interest due to their drastic modulations of physical properties driven by a fundamental tuning of its electronic structures. Thermopower and thermal diffusivity, two major properties to tune thermoelectricity can be varied in such a way that drastic changes can be addressed in very small temperature ranges close to room temperature. Herein we report on the recent progress of polychalcogenide and chalcogenide halides with the mobile d 10 ions Ag and Cu putting the main focus on silver compounds.