Enhanced and robust contrast in CEST MRI: Saturation pulse shape design via optimal control.

PURPOSE: To employ optimal control for the numerical design of Chemical Exchange Saturation Transfer (CEST) saturation pulses to maximize contrast and stability against B 0 $$ {\mathrm{B}}_0 $$ inhomogeneities. THEORY AND METHODS: We applied an optimal control framework for the design pulse shapes for CEST saturation pulse trains. The cost functional minimized both the pulse energy and the discrepancy between the corresponding CEST spectrum and the target spectrum based on a continuous radiofrequency (RF) pulse. The optimization is subject to hardware limitations. In measurements on a 7 T preclinical scanner, the optimal control pulses were compared to continuous-wave and Gaussian saturation methods. We conducted a comparison of the optimal control pulses with Gaussian, block pulse trains, and adiabatic spin-lock pulses. RESULTS: The optimal control pulse train demonstrated saturation levels comparable to continuous-wave saturation and surpassed Gaussian saturation by up to 50 % in phantom measurements. In phantom measurements at 3 T the optimized pulses not only showcased the highest CEST contrast, but also the highest stability against field inhomogeneities. In contrast, block pulse saturation resulted in severe artifacts. Dynamic Bloch-McConnell simulations were employed to identify the source of these artifacts, and underscore the B 0 $$ {\mathrm{B}}_0 $$ robustness of the optimized pulses. CONCLUSION: In this work, it was shown that a substantial improvement in pulsed saturation CEST imaging can be achieved by using Optimal Control design principles. It is possible to overcome the sensitivity of saturation to B0 inhomogeneities while achieving CEST contrast close to continuous wave saturation.

Robust dual-angle T 1 $$ {T}_1 $$ measurement in magnetization transfer spectroscopy by time-optimal control.

Magnetization transfer spectroscopy relies heavily on the robust determination of T 1 $$ {T}_1 $$ relaxation times of nuclei participating in metabolic exchange. Challenges arise due to the use of surface RF coils for transmission (high B 1 + $$ {B}_1^{+} $$ variation) and the broad resonance band of most X nuclei. These challenges are particularly pronounced when fast T 1 $$ {T}_1 $$ mapping methods, such as the dual-angle method, are employed. Consequently, in this work, we develop resonance offset and B 1 + $$ {B}_1^{+} $$ robust excitation RF pulses for 31P magnetization transfer spectroscopy at 7T through ensemble-based time-optimal control. In our approach, we introduce a cost functional for designing robust pulses, incorporating the full Bloch equations as constraints, which are solved using symmetric operator splitting techniques. The optimal control design of the RF pulses developed demonstrates improved accuracy, desired phase properties, and reduced RF power when applied to dual-angle T 1 $$ {T}_1 $$ mapping, thereby improving the precision of exchange-rate measurements, as demonstrated in a preclinical in vivo study quantifying brain creatine kinase activity.

Reactivity of Superbasic Carbanions Generated via Reductive Radical-Polar Crossover in the Context of Photoredox Catalysis.

Photocatalytic reactions involving a reductive radical-polar crossover (RRPCO) generate intermediates with carbanionic reactivity. Many of these proposed intermediates resemble highly reactive organometallic compounds. However, conditions of their formation are generally not tolerated by their isolated organometallic versions and often a different reactivity is observed. Our investigations on their nature and reactivity under commonly used photocatalytic conditions demonstrate that these intermediates are indeed best described as free, superbasic carbanions capable of deprotonating common polar solvents usually assumed to be inert such as acetonitrile, dimethylformamide, and dimethylsulfoxide. Their basicity not only towards solvents but also towards electrophiles, such as aldehydes, ketones, and esters, is comparable to the reactivity of isolated carbanions in the gas-phase. Previously unsuccessful transformations thought to result from a lack of reactivity are explained by their high reactivity towards the solvent and weakly acidic protons of reaction partners. An intuitive explanation for the mode of action of photocatalytically generated carbanions is provided, which enables methods to verify reaction mechanisms proposed to involve an RRPCO step and to identify the reasons for the limitations of current methods.

Rational Approximation of Golden Angles: Accelerated Reconstructions with Simple and Numerically Reproducible Radial Sampling.

PURPOSE: To develop a generic radial sampling scheme that combines the advantages of golden ratio sampling with simplicity of equidistant angular patterns. The irrational angle between consecutive spokes in golden ratio based sampling schemes enables a flexible retrospective choice of temporal resolution, while preserving good coverage of k-space for each individual bin. Nevertheless, irrational increments prohibit precomputation of the point-spread function (PSF), can lead to numerical problems, and require more complex processing steps. To avoid these problems, a new sampling scheme based on a rational approximation of golden angles (RAGA) is developed. METHODS: The theoretical properties of RAGA sampling are mathematically derived. Sidelobe-to-peak ratios (SPR) are numerically computed and compared to the corresponding golden ratio sampling schemes. The sampling scheme is implemented in the BART toolbox and in a radial gradient-echo sequence. Feasibility is shown for quantitative imaging in a phantom and a cardiac scan of a healthy volunteer. RESULTS: RAGA sampling can accurately approximate golden ratio sampling and has almost identical PSF and SPR. In contrast to golden ratio sampling, each frame can be reconstructed with the same equidistant trajectory using different sampling masks, and the angle of each acquired spoke can be encoded as a small index, which simplifies processing of the acquired data. CONCLUSION: RAGA sampling provides the advantages of golden ratio sampling while simplifying data processing, rendering it a valuable tool for dynamic and quantitative MRI.

Whole-Cerebrum distortion-free three-dimensional pseudo-continuous arterial spin labeling at 7T.

Fulfilling potentials of ultrahigh field for pseudo-Continuous Arterial Spin Labeling (pCASL) has been hampered by B1/B0 inhomogeneities that affect pCASL labeling, background suppression (BS), and the readout sequence. This study aimed to present a whole-cerebrum distortion-free three-dimensional (3D) pCASL sequence at 7T by optimizing pCASL labeling parameters, BS pulses, and an accelerated Turbo-FLASH (TFL) readout. A new set of pCASL labeling parameters (Gave = 0.4 mT/m, Gratio = 14.67) was proposed to avoid interferences in bottom slices while achieving robust labeling efficiency (LE). An OPTIM BS pulse was designed based on the range of B1/B0 inhomogeneities at 7T. A 3D TFL readout with 2D-CAIPIRINHA undersampling (R = 2 × 2) and centric ordering was developed, and the number of segments (Nseg) and flip angle (FA) were varied in simulation to achieve the optimal trade-off between SNR and spatial blurring. In-vivo experiments were performed on 19 subjects. The results showed that the new set of labeling parameters effectively achieved whole-cerebrum coverage by eliminating interferences in bottom slices while maintaining a high LE. The OPTIM BS pulse achieved 33.3% higher perfusion signal in gray matter (GM) than the original BS pulse with a cost of 4.8-fold SAR. Incorporating a moderate FA (8°) and Nseg (2), whole-cerebrum 3D TFL-pCASL imaging was achieved with a 2 × 2 × 4 mm3 resolution without distortion and susceptibility artifacts compared to 3D GRASE-pCASL. In addition, 3D TFL-pCASL showed a good to excellent test-retest repeatability and potential of higher resolution (2 mm isotropic). The proposed technique also significantly improved SNR when compared to the same sequence at 3T and simultaneous multislice TFL-pCASL at 7T. By combining a new set of labeling parameters, OPTIM BS pulse, and accelerated 3D TFL readout, we achieved high resolution pCASL at 7T with whole-cerebrum coverage, detailed perfusion and anatomical information without distortion, and sufficient SNR.

Whole-Cerebrum distortion-free three-dimensional pseudo-Continuous Arterial Spin Labeling at 7T.

Fulfilling potentials of ultrahigh field for pseudo-Continuous Arterial Spin Labeling (pCASL) has been hampered by B1/B0 inhomogeneities that affect pCASL labeling, background suppression (BS), and the readout sequence. This study aimed to present a whole-cerebrum distortion-free three-dimensional (3D) pCASL sequence at 7T by optimizing pCASL labeling parameters, BS pulses, and an accelerated Turbo-FLASH (TFL) readout. A new set of pCASL labeling parameters (Gave=0.4mT/m, Gratio=14.67) was proposed to avoid interferences in bottom slices while achieving robust labeling efficiency (LE). An OPTIM BS pulse was designed based on the range of B1/B0 inhomogeneities at 7T. A 3D TFL readout with 2D-CAIPIRINHA undersampling (R=2×2) and centric ordering was developed, and the number of segments (Nseg) and flip angle (FA) were varied in simulation to achieve the optimal trade-off between SNR and spatial blurring. In-vivo experiments were performed on 19 subjects. The results showed that the new set of labeling parameters effectively achieved whole-cerebrum coverage by eliminating interferences in bottom slices while maintaining a high LE. The OPTIM BS pulse achieved 33.3% higher perfusion signal in gray matter (GM) than the original BS pulse with a cost of 4.8-fold SAR. Incorporating a moderate FA (8 ° ) and Nseg (2), whole-cerebrum 3D TFL-pCASL imaging was achieved with a 2×2×4 mm 3 resolution without distortion and susceptibility artifacts compared to 3D GRASE-pCASL. In addition, 3D TFL-pCASL showed a good to excellent test-retest repeatability and potential of higher resolution (2 mm isotropic). The proposed technique also significantly improved SNR when compared to the same sequence at 3T and simultaneous multislice TFL-pCASL at 7T. By combining a new set of labeling parameters, OPTIM BS pulse, and accelerated 3D TFL readout, we achieved high resolution pCASL at 7T with whole-cerebrum coverage, detailed perfusion and anatomical information without distortion, and sufficient SNR.

Gait pattern analysis in the home environment as a key factor for the reliable assessment of shunt responsiveness in patients with idiopathic normal pressure hydrocephalus.

Background: The identification of patients with gait disturbance associated with idiopathic normal pressure hydrocephalus (iNPH) is challenging. This is due to the multifactorial causes of gait disturbance in elderly people and the single moment examination of laboratory tests. Objective: We aimed to assess whether the use of gait sensors in a patient's home environment could help establish a reliable diagnostic tool to identify patients with iNPH by differentiating them from elderly healthy controls (EHC). Methods: Five wearable inertial measurement units were used in 11 patients with iNPH and 20 matched EHCs. Data were collected in the home environment for 72 h. Fifteen spatio-temporal gait parameters were analyzed. Patients were examined preoperatively and postoperatively. We performed an iNPH sub-group analysis to assess differences between responders vs. non-responders. We aimed to identify parameters that are able to predict a reliable response to VP-shunt placement. Results: Nine gait parameters significantly differ between EHC and patients with iNPH preoperatively. Postoperatively, patients with iNPH showed an improvement in the swing phase (p = 0.042), and compared to the EHC group, there was no significant difference regarding the cadence and traveled arm distance. Patients with a good VP-shunt response (NPH recovery rate of ≥5) significantly differ from the non-responders regarding cycle time, cycle time deviation, number of steps, gait velocity, straight length, stance phase, and stance to swing ratio. A receiver operating characteristic analysis showed good sensitivity for a preoperative stride length of ≥0.44 m and gait velocity of ≥0.39 m/s. Conclusion: There was a significant difference in 60% of the analyzed gait parameters between EHC and patients with iNPH, with a clear improvement toward the normalization of the cadence and traveled arm distance postoperatively, and a clear improvement of the swing phase. Patients with iNPH with a good response to VP-shunt significantly differ from the non-responders with an ameliorated gait pattern.

Controlled Synthesis of Platinum and Silver Nanoparticles Using Multivalent Ligands.

Here, the controlled formation of platinum nanoparticles (PtNPs) and silver nanoparticles (AgNPs) using amine-functionalized multivalent ligands are reported. The effects of reaction temperature and ligand multivalency on the growth kinetics, size, and shape of PtNPs and AgNPs were systematically studied by performing a stepwise and a one-step process. PtNPs and AgNPs were prepared in the presence of amine ligands using platinum (II) acetylacetonate and silver (I) acetylacetonate, respectively. The effects of ligands and temperature on the formation of PtNPs were studied using a transmission electron microscope (TEM). For the characterization of AgNPs, additionally, ultraviolet-visible (UV-Vis) absorption was employed. The TEM measurements revealed that PtNPs prepared at different temperatures (160-200 °C, in a stepwise process) are monodispersed and of spherical shape regardless of the ligand multivalency or reaction temperature. In the preparation of PtNPs by the one-step process, ligands affect the shape of the PtNPs, which can be explained by the affinity of the ligands. The TEM and UV-Vis absorption studies on the formation of AgNPs with mono-, di-, and trivalent ligands showed narrower size distributions, while increasing the temperature from 80 °C to 120 °C and with a trivalent ligand in a one-step process.

Advanced design of MRI inversion pulses for inhomogeneous field conditions by optimal control.

Non-selective inversion pulses find widespread use in MRI applications, where requirements on them are increasingly demanding. With the use of high and ultra-high field strength systems, robustness to Δ B 0 and B 1 + inhomogeneities, while tackling SAR and hardware limitations, has rapidly become important. In this work, we propose a time-optimal control framework for the optimization of Δ B 0 - and B 1 + -robust inversion pulses. Robustness is addressed by means of ensemble formulations, while allowing inclusion of hardware and energy limitations. The framework is flexible and performs excellently for various optimization goals. The optimization results are analyzed extensively in numerical experiments. Furthermore, they are validated, and compared with adiabatic RF pulses, in various phantom and in vivo measurements on a 3 T MRI system.

Personality and social environment predict cognitive performance in common marmosets (Callithrix jacchus).

Consistent inter-individual variation in cognition has been increasingly explored in recent years in terms of its patterns, causes and consequences. One of its possible causes are consistent inter-individual differences in behaviour, also referred to as animal personalities, which are shaped by both the physical and the social environment. The latter is particularly relevant for group-living species like common marmosets (Callithrix jacchus), apt learners that display substantial variation in both their personality and cognitive performance, yet no study to date has interlinked these with marmosets' social environment. Here we investigated (i) consistency of learning speed, and (ii) whether the PCA-derived personality traits Exploration-Avoidance and Boldness-Shyness as well as the social environment (i.e., family group membership) are linked with marmosets' speed of learning. We tested 22 individuals in series of personality and learning-focused cognitive tests, including simple motor tasks and discrimination learning tasks. We found that these marmosets showed significant inter-individual consistency in learning across the different tasks, and that females learned faster than males. Further, bolder individuals, and particularly those belonging to certain family groups, learned faster. These findings indicate that both personality and social environment affect learning speed in marmosets and could be important factors driving individual variation in cognition.

Revealing the formation mechanism and band gap tuning of Sb2S3 nanoparticles.

Sb2S3 is a promising nanomaterial for application in solar cells and in the fields of electronics and optoelectronics. Herein, Sb2S3 nanoparticles were prepared via the hot-injection approach. In contrast to earlier work, the reaction temperature was decreased to 150 °C so that the reaction was slowed down and could be stopped at defined reaction stages. Thereby, the formation mechanism of the nanomaterial and the associated kinetics could be revealed. Based on morphological and structural analyses, it is suggested that seed particles (type 0) formed immediately after injecting the antimony precursor into the sulfur precursor. These seeds fused to form amorphous nanoparticles (type I) that contained a lower percentage of sulfur than that corresponding to the expected stoichiometric ratio of Sb2S3. The reason for this possibly lies in the formation of an oxygen- or carbon-containing intermediate during the seeding process. Afterward, the type I nanoparticles aggregated into larger amorphous nanoparticles (type II) in a second hierarchical assembly process and formed superordinate structures (type III). This process was followed by the crystallization of these particles and a layer-like growth of the crystalline particles by an Ostwald ripening process at the expense of the amorphous particles. It was demonstrated that the kinetic control of the reaction allowed tuning of the optical band gap of the amorphous nanoparticles in the range of 2.2-2.0 eV. On the contrary, the optical band gap of the crystalline particles decreased to a value of 1.7 eV and remained constant when the reaction progressed. Based on the proposed formation mechanism, future syntheses for Sb2S3 particles can be developed, allowing tuning of the particle properties in a broad range. In this way, the selective use of this material in a wide range of applications will become possible.

Accuracy and performance analysis for Bloch and Bloch-McConnell simulation methods.

PURPOSE: To introduce new solution methods for the Bloch and Bloch-McConnell equations and compare them quantitatively to different known approaches. THEORY AND METHODS: A new exact solution per time step is derived by means of eigenvalues and generalized eigenvectors. Fast numerical solution methods based on asymmetric and symmetric operator splitting, which are already known for the Bloch equations, are extended to the Bloch-McConnell equations. Those methods are compared to other numerical methods including spin domain, one-step and multi-step methods, and matrix exponential. Error metrics are introduced based on the exact solution method, which allows to assess the accuracy of each solution method quantitatively for arbitrary example data. RESULTS: Accuracy and performance properties for nine different solution methods are analyzed and compared in extensive numerical experiments including various examples for non-selective and slice-selective MR imaging applications. The accuracy of the methods heavily varies, in particular for short relaxation times and long pulse durations. CONCLUSION: In absence of relaxation effects, the numerical results confirm the rotation matrices approach as accurate and computationally efficient Bloch solution method. Otherwise, as well as for the Bloch-McConnell equations, symmetric operator splitting methods are recommended due to their excellent numerical accuracy paired with efficient run time.

The presence of liver cirrhosis is a strong negative predictor of survival for patients admitted to the intensive care unit - Cirrhosis in intensive care patients.

BACKGROUND AND AIMS: Liver cirrhosis is a systemic disease that substantially impacts the body's physiology, especially in advanced stages. Accordingly, the outcome of patients with cirrhosis requiring intensive care treatment is poor. We aimed to analyze the impact of cirrhosis on mortality of intensive care unit (ICU) patients compared to other frequent chronic diseases and conditions. METHODS: In this retrospective study, patients admitted over three years to the ICU of the Department of Medicine of the University Hospital Frankfurt were included. Patients were matched for age, gender, pre-existing conditions, simplified acute physiology score (SAPS II), and therapeutic intervention scoring system (TISS). RESULTS: A total of 567 patients admitted to the ICU were included in the study; 99 (17.5 %) patients had liver cirrhosis. A total of 129 patients were included in the matched cohort for the sensitivity analysis. In-hospital mortality was higher in cirrhotic patients than non-cirrhotic patients (p < 0.0001) in the entire and matched cohort. Liver cirrhosis remained one of the strongest independent predictors of in-hospital mortality (entire cohort p = 0.001; matched cohort p = 0.03) along with dialysis and need for transfusion in the multivariate logistic regression analysis. Furthermore, in the cirrhotic group, the need for kidney replacement therapy (p < 0.001) and blood transfusion (p < 0.001) was significantly higher than in the non-cirrhotic group.  CONCLUSIONS: In the presented study, liver cirrhosis was one of the strongest predictors of in-hospital mortality in patients needing intensive care treatment along with dialysis and the need for ventilation. Therefore, concerted efforts are needed to improve cirrhotic patients' outcomes, prevent disease progression, and avoid complications with the need for ICU treatment in the early stages of the disease.

Effect of different silica coatings on the toxicity of upconversion nanoparticles on RAW 264.7 macrophage cells.

Upconversion nanoparticles (UCNPs), consisting of NaYF4 doped with 18% Yb and 2% Er, were coated with microporous silica shells with thickness values of 7 ± 2 and 21 ± 3 nm. Subsequently, the negatively charged particles were functionalized with N-(6-aminohexyl)-3-aminopropyltrimethoxysilane (AHAPS), which provide a positive charge to the nanoparticle surface. Inductively coupled plasma optical emission spectrometry (ICP-OES) measurements revealed that, over the course of 24h, particles with thicker shells release fewer lanthanide ions than particles with thinner shells. However, even a 21 ± 3 nm thick silica layer does not entirely block the disintegration process of the UCNPs. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays and cell cytometry measurements performed on macrophages (RAW 264.7 cells) indicate that cells treated with amino-functionalized particles with a thicker silica shell have a higher viability than those incubated with UCNPs with a thinner silica shell, even if more particles with a thicker shell are taken up. This effect is less significant for negatively charged particles. Cell cycle analyses with amino-functionalized particles also confirm that thicker silica shells reduce cytotoxicity. Thus, growing silica shells to a sufficient thickness is a simple approach to minimize the cytotoxicity of UCNPs.

The pathologist and "short-term rector" Albert Dietrich (1873-1961) and his ambivalent relationship with the Nazi regime : Not Nazi enough?

Throughout his professional life, the pathologist Albert Dietrich devoted himself to researching and combating cancer. Due to his considerable reputation and success, he was one of the first doctors to be awarded the Paracelsus Medal for his scientific services in 1952.However, Dietrich's role in the Third Reich was - and still is - far less defined. In May 1933, he became rector of the Eberhard Karls University in Tübingen, which at that time was one of the most Nazi-oriented universities. However, his term of office was short - by the end of 1933 he had already been replaced by the protestant theologian Karl Fezer.This article sheds light on Dietrich's ambivalent relationship to National Socialism and analyzes and discusses the background to his dismissal, his later (also politically influenced) emeritus status (1938/39), and his entry into the NSDAP, which took place at retirement age (1941). The study is based on archival sources partly evaluated for the first time and on a reanalysis of the relevant research literature.The study shows that Dietrich was targeted by individual Nazi decision-makers primarily because he advocated a supposedly "liberalist" university policy. Dietrich thus ultimately stands for a type of university lecturer who renounced a decidedly Nazi stance in public without, however, placing himself in a critical relationship to Nazi ideology. Against this background, statements from the postwar period that saw him retrospectively near Nazi opposition are to be classified as the formation of legends.

Virchow medallists and honorary members of the German Society of Pathology and their relationship with National Socialism : A cross-sectional study.

The present study focuses on the group of pathologists who (1) were appointed honorary members or bearers of the Rudolf Virchow Medal by the German Society for Pathology (DGP) and (2) experienced the Third Reich as a citizen of the Third Reich. In particular, it examines the relationship between those distinguished persons and National Socialism, and, at the same time, the criteria of the professional society when awarding such honors. Specifically, it is important to clarify what role the DGP officials ascribed to the political stance or experience of the candidates in the Nazi dictatorship during the selection process: were there victims of the Nazis among the honorees whose repressive experiences and personal fates were intended to be acknowledged in this way? Of equal interest is the counter-question: were pathologists honored who had made (party) political commitments to National Socialism during the Third Reich?A total of nine Virchow medallists and three honorary members met the inclusion criteria. None of those affected belonged to the group of pathologists who suffered injustice during the Third Reich or who could be described as victims of the Nazis. On the other hand, four of the nine German Virchow medal winners and one of the three honorary members had joined the National Socialist Party and to some extent other Nazi organisations. Obviously, previous closeness to National Socialism was not a decisive factor in the selection of honorary members and Virchow medallists and, in particular, was not an exclusion criterion.The aforementioned results correspond to the findings of a parallel study, in which the political past of the German DGP chairmen appointed up to 1986 was examined. This showed that two thirds of them had joined the National Socialist Party during the Third Reich.

[Walter Büngeler (1900-1987) : Nazi victim or political influencer in Brazil?] / Walter Büngeler (1900­1987) : Opfer der NS-Zeit oder nationalsozialistischer Kontaktmann in Brasilien?

Walter Büngeler is one of the best known German pathologists of the 20th century. He became internationally known for his basic research on leukaemia and the pathology of tumours. In 1936 he left Europe for Brazil but returned in 1942. After 1945, he staged himself as a political victim who had been expelled first by the National Socialists and later from Brazil. In fact, with this portrayal he succeeded in passing the denazification procedure without any damage and in continuing and considerably expanding his university career. Until the recent past, Büngeler was described in the relevant literature as a Nazi critic or victim. But does the presentation handed down by Büngeler stand up to a critical examination of the facts?On the basis of contemporary sources, the article reveals serious differences between Büngeler's statements and historical facts. It can be shown that Büngeler's allegations in denazification were incorrect in all relevant aspects.

German pathologist Walter Büngeler (1900-1987)-Nazi victim or political influencer in Brazil?

One of the most wellknown German pathologists of the twentieth century, Walter Büngeler became internationally known for his elemental research on leukemia and the pathology of tumors. In 1936, Büngeler left Nazi Germany for Brazil, but returned to Germany in 1942. After the war ended in 1945, Büngeler portrayed himself as a political victim who had been expelled first by the National Socialists and later by the Brazilian government, and in fact, he was able to successfully perpetuate this image and emerged unscathed from his de-Nazification procedure, continuing on to a successful university career with stations in Kiel and Munich as both professor and dean, as well as a term as DGP president. Up until very recently, Büngeler was portrayed in literature as a victim and critic of Nazism. Does this self-portrayal stand up to a critical examination of the facts? It is precisely this question that is the focus of this article. The analysis draws upon primary sources; namely, Büngeler's own claims from a curriculum vitae filled out in 1943 as well as his de-Nazification file from the post-war period. This article exposes significant contradictions between these two sources. The statements Büngeler made in his de-Nazification file can be verified as false in all relevant aspects. Nevertheless, Büngeler managed to create a wide-reaching and successful version of himself; a picture which persisted until only very recently.

Versatile Visible-Light-Driven Synthesis of Asymmetrical Phosphines and Phosphonium Salts.

Asymmetrically substituted tertiary phosphines and quaternary phosphonium salts are used extensively in applications throughout industry and academia. Despite their significance, classical methods to synthesize such compounds often demand either harsh reaction conditions, prefunctionalization of starting materials, highly sensitive organometallic reagents, or expensive transition-metal catalysts. Mild, practical methods thus remain elusive, despite being of great current interest. Herein, we describe a visible-light-driven method to form these products from secondary and primary phosphines. Using an inexpensive organic photocatalyst and blue-light irradiation, arylphosphines can be both alkylated and arylated using commercially available organohalides. In addition, the same organocatalyst can be used to transform white phosphorus (P4 ) directly into symmetrical aryl phosphines and phosphonium salts in a single reaction step, which has previously only been possible using precious metal catalysis.

[Virchow medallists and honorary members of the German Society for Pathology and their relationship with National Socialism : A cross-sectional study. German version]. / Virchow-Medaillenträger und Ehrenmitglieder der DGP und ihr Verhältnis zum Nationalsozialismus : Eine Querschnittsstudie.

The present study focuses on the group of pathologists who (1) were appointed honorary members or bearers of the Rudolf Virchow Medal by the German Society for Pathology (DGP) and (2) experienced the "Third Reich" as a citizen of the "Third Reich". In particular, it examines the relationship between those distinguished persons and National Socialism, and, at the same time, the criteria of the professional society when awarding such honours. Specifically, it is important to clarify what role the DGP officials ascribed to the political stance or experience of the candidates in the Nazi dictatorship during the selection process: were there victims of the Nazis among the honourees whose repressive experiences and personal fates were intended to be acknowledged in this way? Of equal interest is the counter-question: were pathologists honoured who had made (party)political commitments to National Socialism during the "Third Reich"?A total of 9 Virchow medallists and 3 honorary members met the inclusion criteria. None of those affected belonged to the group of pathologists who suffered injustice during the "Third Reich" or who could be described as victims of the Nazis. On the other hand, 4 of the 9 German Virchow medal winners and 1 of the 3 honorary members had joined the National Socialist Party and to some extent other Nazi organisations. Obviously, previous closeness to National Socialism was not a decisive factor in the selection of honorary members and Virchow medallists and, in particular, was not an exclusion criterion.The aforementioned results correspond to the findings of a parallel study, in which the political past of the German DGP chairmen appointed up to 1986 was examined. This showed that two thirds of them had joined the National Socialist Party during the "Third Reich".