Testing quantum electrodynamics in extreme fields using helium-like uranium.

Quantum electrodynamics (QED), the quantum field theory that describes the interaction between light and matter, is commonly regarded as the best-tested quantum theory in modern physics. However, this claim is mostly based on extremely precise studies performed in the domain of relatively low field strengths and light atoms and ions1-6. In the realm of very strong electromagnetic fields such as in the heaviest highly charged ions (with nuclear charge Z ≫ 1), QED calculations enter a qualitatively different, non-perturbative regime. Yet, the corresponding experimental studies are very challenging, and theoretical predictions are only partially tested. Here we present an experiment sensitive to higher-order QED effects and electron-electron interactions in the high-Z regime. This is achieved by using a multi-reference method based on Doppler-tuned X-ray emission from stored relativistic uranium ions with different charge states. The energy of the 1s1/22p3/2 J = 2 → 1s1/22s1/2 J = 1 intrashell transition in the heaviest two-electron ion (U90+) is obtained with an accuracy of 37 ppm. Furthermore, a comparison of uranium ions with different numbers of bound electrons enables us to disentangle and to test separately the one-electron higher-order QED effects and the bound electron-electron interaction terms without the uncertainty related to the nuclear radius. Moreover, our experimental result can discriminate between several state-of-the-art theoretical approaches and provides an important benchmark for calculations in the strong-field domain.

Toward the development of sensors for lung cancer: The adsorption of 1-propanol on hydrophobic zeolites.

A healthy breath is mainly composed of water, carbon dioxide, molecular nitrogen, and oxygen and it contains many species, in small quantities, which are related to the ambient atmosphere and the metabolism. The breath of a person affected by lung cancer presents a concentration of 1-propanol higher than usual. In this context, the development of specific sensors to detect 1-propanol from breath is of high interest. The amount of propanol usually detected on the breath is of few ppb; this small quantity is a handicap for a reliable diagnostic. This limitation can be overcome if the sensor is equipped with a pre-concentrator. Our studies aim to provide an efficient material playing this role. This will contribute to the development of reliable and easy to use lung cancer detectors. For this, we investigate the properties of a few hydrophobic porous materials (chabazite, silicalite-1, and dealuminated faujasite). Hydrophobic structures are used to avoid saturation of materials by the water present in the exhaled breath. Our experimental and simulation results suggest that silicalite -1 (MFI) is the most suitable structure to be used as a pre-concentrator.

Stochastic epigenetic mutations as possible explanation for phenotypical discordance among twins with congenital hypothyroidism.

PURPOSE: The elevated frequency of discordance for congenital hypothyroidism (CH) phenotype between monozygotic twins suggests the involvement of non-mendelian mechanisms. The aim of the study was to investigate the role of epigenetics in CH pathogenesis. METHODS: A genome-wide DNA methylation analysis was performed on the peripheral blood of 23 twin pairs (10 monozygotic and 13 dizygotic), 4 concordant and 19 discordant pairs for CH at birth. RESULTS: Differential methylation analysis did not show significant differences in methylation levels between CH cases and controls, but a different methylation status of several genes may explain the CH discordance of a monozygotic twin couple carrying a monoallelic nonsense mutation of DUOX2. In addition, the median number of hypo-methylated Stochastic Epigenetic Mutations (SEMs) resulted significantly increased in cases compared to controls. The prioritization analysis for CH performed on the genes epimutated exclusively in the cases identified SLC26A4, FOXI1, NKX2-5 and TSHB as the genes with the highest score. The analysis of significantly SEMs-enriched regions led to the identification of two genes (FAM50B and MEG8) that resulted epigenetically dysregulated in cases. CONCLUSION: Epigenetic modifications may potentially account for CH pathogenesis and explain discordance among monozygotic twins.

The use of online video consultations in the aftercare of orthopedic patients: a prospective case-control study.

BACKGROUND: Video consultations have proven to be an efficient source of support for patient-doctor interactions and have become increasingly used in orthopedics, especially during the COVID-19 pandemic. This study analyzed both patients' and doctors' acceptance of an orthopedic telemedical consultation (OTC) and compared the results of OTC examinations to the results of live consultation (LC) to identify discrepancies. METHODS: The study was carried out in an orthopedic department of a German hospital between 2019 and 2020. After written informed consent was obtained, patients voluntarily presented for follow-up by OTC and LC. The experience with and attitudes toward OTC among both patients and doctors was evaluated (using Likert scale-scored and open questions, 26 to 28 items). The results of the OTC and LC examinations were compared using a 12-item checklist. The data were analyzed by quantitative and qualitative statistics. RESULTS: A total of 53 patients were included, each of whom completed an OTC and an LC. The OTC was rated as pleasant, and the experience was rated as very satisfying (average rating on a 5-point Likert scale, with 1 indicating strong agreement: doctors: 1.2; patients: 1.3). Various technical and organizational challenges were identified. Compared to LC, OTC showed no significant differences in patient history or in inspection, palpation, or active range of motion results. Only for the functional or passive joint assessment did LC show significantly higher suitability (p < 0.05) than OTC. Recommendations for further procedures did not differ significantly between OTC and LC. CONCLUSIONS: Because of the high acceptance and the objective benefits of OTC and the similarity of clinical results with LC, OTC is recommendable for orthopedic follow-up examinations. To better assess joint functionality, meaningful digital alternatives for established examination methods should be further investigated.

Autoimmune polyendocrine syndrome type 1: an Italian survey on 158 patients.

BACKGROUND: Autoimmune Polyglandular Syndrome type 1 (APS-1) is a rare recessive inherited disease, caused by AutoImmune Regulator (AIRE) gene mutations and characterized by three major manifestations: chronic mucocutaneous candidiasis (CMC), chronic hypoparathyroidism (CH) and Addison's disease (AD). METHODS: Autoimmune conditions and associated autoantibodies (Abs) were analyzed in 158 Italian patients (103 females and 55 males; F/M 1.9/1) at the onset and during a follow-up of 23.7 ± 15.1 years. AIRE mutations were determined. RESULTS: The prevalence of APS-1 was 2.6 cases/million (range 0.5-17 in different regions). At the onset 93% of patients presented with one or more components of the classical triad and 7% with other components. At the end of follow-up, 86.1% had CH, 77.2% AD, 74.7% CMC, 49.5% premature menopause, 29.7% autoimmune intestinal dysfunction, 27.8% autoimmune thyroid diseases, 25.9% autoimmune gastritis/pernicious anemia, 25.3% ectodermal dystrophy, 24% alopecia, 21.5% autoimmune hepatitis, 17% vitiligo, 13.3% cholelithiasis, 5.7% connective diseases, 4.4% asplenia, 2.5% celiac disease and 13.9% cancer. Overall, 991 diseases (6.3 diseases/patient) were found. Interferon-ω Abs (IFNωAbs) were positive in 91.1% of patients. Overall mortality was 14.6%. The AIRE mutation R139X was found in 21.3% of tested alleles, R257X in 11.8%, W78R in 11.4%, C322fsX372 in 8.8%, T16M in 6.2%, R203X in 4%, and A21V in 2.9%. Less frequent mutations were present in 12.9%, very rare in 9.6% while no mutations in 11% of the cases. CONCLUSIONS: In Italy, APS-1 is a rare disorder presenting with the three major manifestations and associated with different AIRE gene mutations. IFNωAbs are markers of APS-1 and other organ-specific autoantibodies are markers of clinical, subclinical or potential autoimmune conditions.

The association between challenging behaviour and symptoms of post-traumatic stress disorder in people with intellectual disabilities: a Bayesian mediation analysis approach.

BACKGROUND: A preponderance of behavioural symptoms is assumed to be the main difference in the manifestation of symptoms of post-traumatic stress disorder (PTSD) in people with intellectual disability (ID). However, no study so far has assessed the relationship between challenging behaviour (CB) and PTSD. The present study aims to explore this relationship by exploring whether CB is directly related to trauma exposure or whether this relationship is mediated through core symptoms of PTSD. METHODS: Trauma exposure and current symptoms of PTSD were assessed in 43 adults with mild to moderate ID. Parallel versions were administered to 43 caregivers, including the Aberrant Behaviour Checklist to measure CB. Bayesian mediation analyses were conducted using self-rated and informant-rated data. RESULTS: The self-report data showed no associations of CB with trauma exposure or PTSD symptoms. The association between informant-rated trauma exposure and irritability was mediated by severity and frequency of PTSD symptoms. The associations between informant-reported trauma exposure and the Aberrant Behaviour Checklist subscales hyperactivity and inappropriate speech were mediated by PTSD symptom severity. CONCLUSIONS: The relationship between trauma exposure and CB was mediated by PTSD symptoms. PTSD core symptoms should be considered as underlying causes of CB, highlighting the necessity to explore trauma biography and symptoms of PTSD. The improvement of self-report assessment in people with ID is an important task for future studies.

Reduced leadset selection and performance evaluation in the inverse problem of electrocardiography for reconstructing the ventricularly paced electrograms.

OBJECTIVE: Noninvasive electrocardiographic imaging (ECGI) is used for obtaining high-resolution images of the electrical activity of the heart, and is a powerful method with the potential to detect certain arrhythmias. However, there is no 'best' lead configuration in the literature to measure the torso potentials. This paper evaluates ECGI reconstructions using various reduced leadset configurations, explores whether one can find a common reduced leadset configuration that can accurately reconstruct the electrograms for datasets with different pacing sites, and compares two activation time estimation methods. APPROACH: We used 23 ventricularly-paced datasets with pacing sites on different regions of the epicardium. Starting with a full 192­leadset, we found "optimized" reduced leadsets specific to each dataset; we considered 64­lead and 32­lead configurations. Based on the histogram of individual "optimized" lead selections, we found a common reduced leadset. We compared the ECGI reconstructions and activation times of the individually optimized lead configurations with the common lead configurations. RESULTS: Both 64­lead configurations had similar performances to the 192­leadset. 32­leadset configurations, on the other hand, yielded noisy reconstructions, which affected their performance. SIGNIFICANCE: There are no statistically significant differences in the performance of the inverse solutions when a 64­lead common reduced leadset is used to estimate the electrograms and their respective pacing sites compared to using the full leadset. 32­lead configurations, on the other hand, require a more careful study to improve their performance. The activation time method used significantly affects the pacing site estimation performance, especially with fewer electrodes.

"Block-and-replace" treatment in Graves' disease: experience in a cohort of pediatric patients.

PURPOSE: The "block-and-replace" (BR) method involves the use of a high dose of antithyroid drugs (ATD) with levothyroxine (L-T4). Its use in the management of Graves' disease (GD) is still debated mainly because the frequency of side effects of ATD is dose dependent. We retrospectively studied the effect of medium dose of ATD with L-T4 versus monotherapy with ATD in pediatric patients with unstable GD. METHODS: 28 pediatric patients with GD with unstable response to ATD were treated with L-T4 and medium dose of ATD. We compared the rate of euthyroidism, hypothyroidism and hyperthyroidism episodes observed during treatment with methimazole alone with those observed during the BR approach. We evaluated the occurrence of side effects and the rate of remission in patients treated with ATD + L-T4 therapy and the efficacy of combination therapy to postpone a definitive treatment (radioiodine and thyroidectomy). RESULTS: Patients showed a better control of thyroid function during the BR therapy, presenting fewer episodes of hyperthyroidism and hypothyroidism. No serious side effects during the BR approach were observed. Only one patient went into remission with the ATD + L-T4 therapy. Fifteen patients required a definitive therapy (4 radioiodine, 11 thyroidectomy). The use of BR method has delayed radioiodine treatment for 4.9 years and surgery for 2.9 years. CONCLUSIONS: The BR method does not increase the remission rates. It may be useful to combine L-T4 with a medium dose of methimazole when GD is difficult to manage with methimazole alone. It may represent a therapeutic option to postpone definitive treatments to a suitable age.

X-linked hypophosphatemic rickets: an Italian experts' opinion survey.

BACKGROUND: X-linked hypophosphatemic rickets (XLH) is the first cause of inherited hypophosphatemia and is caused by mutation in the PHEX gene, resulting in excessive expression of the phosphaturic factor FGF23. Symptoms are mainly related to rickets in children and osteomalacia in adults and cause several complications that can be highly invalidating. Due to its rarity, XLH is poorly known and diagnosis is frequently delayed. Conventional treatment is based on oral phosphate salts supplementation and activated vitamin D analogs, which however, cannot cure the disease in most cases. OBJECTIVE: Due to the low prevalence of XLH, an experts' opinion survey was conducted across Italian centers to collect data on XLH and on its management. METHODS: A questionnaire was developed by a group of experts to collect data on XLH epidemiology, diagnosis and treatment in Italy. RESULTS: Data from 10 Italian centers (nine of which pediatric) on 175 patients, followed between 1998 and 2017, were included in the survey. Most patients were followed since childhood and 63 children became adults during the investigated period. The diagnosis was made before the age of 1 and between 1 and 5 years in 11 and 50% of cases, respectively. Clinically apparent bone deformities were present in 95% of patients. These were ranked moderate/severe in 75% of subjects and caused growth stunting in 67% of patients. Other frequent complications included bone pain (40%), dental abscesses (33%), and dental malpositions (53%). Treatment protocols varied substantially among centers. Nephrocalcinosis was observed in 34% of patients. Tertiary hyperparathyroidism developed in 6% of patients. CONCLUSIONS: XLH remains a severe condition with significant morbidities.

Magma Degassing as a Source of Long-Term Seismicity at Volcanoes: The Ischia Island (Italy) Case.

Transient seismicity at active volcanoes poses a significant risk in addition to eruptive activity. This risk is powered by the common belief that volcanic seismicity cannot be forecast, even on a long term. Here we investigate the nature of volcanic seismicity to try to improve our forecasting capacity. To this aim, we consider Ischia volcano (Italy), which suffered similar earthquakes along its uplifted resurgent block. We show that this seismicity marks an acceleration of decades-long subsidence of the resurgent block, driven by degassing of magma that previously produced the uplift, a process not observed at other volcanoes. Degassing will continue for hundreds to thousands of years, causing protracted seismicity and will likely be accompanied by moderate and damaging earthquakes. The possibility to constrain the future duration of seismicity at Ischia indicates that our capacity to forecast earthquakes might be enhanced when seismic activity results from long-term magmatic processes, such as degassing.

Intracranial hemorrhage with direct oral anticoagulants in patients with brain tumors.

Essentials Intracranial hemorrhage (ICH) is common in patients with brain tumors. We compared rates of ICH with DOACs and low molecular weight heparin. DOACs were associated with a lower incidence of ICH in primary brain tumors. DOACs appear safe to administer to patients with brain tumors. SUMMARY: Background Direct oral anticoagulants (DOACs) are efficacious in the treatment of cancer-associated thrombosis but are associated with an increased risk of hemorrhage compared with low-molecular-weight heparin in certain malignancies. Whether the DOACs increase the incidence of intracranial hemorrhage (ICH) in patients with brain tumors is not established. Objectives To determine the cumulative incidence of ICH in DOACs compared with Low-molecular-weight heparin (LMWH) in patients with brain tumors and venous thromboembolism. Patients and methods A retrospective comparative cohort study was performed. Radiographic images for all ICH events were reviewed and the primary endpoint was cumulative incidence of ICH at 12 months following initiation of anticoagulation. Results and conclusions A total of 172 patients with brain tumors were evaluated (42 DOAC and 131 LMWH). In the primary brain tumor cohort (n = 67), the cumulative incidence of any ICH was 0% in patients receiving DOACs vs. 36.8% (95% confidence interval [CI], 22.3-51.3%) in those treated with LMWH, with a major ICH incidence of 18.2% (95% CI, 8.4-31.0). In the brain metastases cohort (n = 105), DOACs did not increase the risk of any ICH relative to enoxaparin, with an incidence of 27.8% (95% CI, 5.5-56.7%) compared with 52.9% (95% CI, 37.4-66.2%). Similarly, DOAC did not increase the incidence of major ICH in brain metastases, with a cumulative incidence 11.1% (95% CI, 0.5-40.6%) vs. 17.8% (95% CI, 10.2-27.2%). We conclude that DOACs are not associated with an increased incidence of ICH relative to LMWH in patients with brain metastases or primary brain tumors.

Treatment of onychomycosis using a 1064-nm diode laser with or without topical antifungal therapy: a single-center, retrospective analysis in 56 patients.

BACKGROUND: Currently available treatment options for onychomycosis such as topical and systemic antifungals are often of limited efficacy, difficult to administer or associated with relevant side effects. Non-ablative laser therapy is proposed to represent a safe alternative without the disadvantages of drugs. Yet, to date, the efficacy of laser therapy for onychomycosis is discussed controversially. Against this background, we performed a systematic retrospective analysis of our clinical experience of 4 years of onychomycosis treatment applying a long-pulsed 1.064-nm diode laser. METHODS: We retrospectively evaluated the records of 56 patients with microscopic and culturally proven onychomycosis affecting a toenail of the hallux and other toes, who had been treated with a long-pulsed 1.064-nm diode laser (FOX, A.C.R. Laser GmbH, Nuremberg) during the time period of July 2013-December 2016 with or without concomitant topical antifungals. Thereof, 27 patients received laser treatment and 29 patients received laser treatment in combination with local antifungals. We conducted a mean of 3.9 laser treatments at 2-6-week intervals. The primary endpoint of our analysis was clinical improvement; secondary endpoints were complete remission of fungal pathogens in fungal culture and in microscopy. RESULTS: Clinical improvement was achieved in 56% of patients treated with laser only after a mean of 4.5 treatments and in 69% of patients treated with laser in combination with topical antifungals after a mean of 3.6 treatments. Cultural healing was detected in 63% of patients treated with laser only after a mean of 5.4 treatments, vs. 86% of patients treated with laser and concomitant topical antifungals after a mean of 4.8 treatments. Microscopic healing (complete healing) with the absence of fungal pathogens was achieved in 11% of patients after a mean of 4.7 treatments with laser only, vs. 21% of patients treated with laser and concomitant topical antifungals after a mean of 4 treatments. No relevant adverse effects were observed. CONCLUSIONS: The 1.064-nm diode laser is an effective and safe option for the treatment of onychomycosis. Of note, the combination with topical antifungals will increase overall treatment efficacy and reduce the time to healing. Particularly, patients with contraindications against systemic antifungals may benefit from this multimodal therapeutic approach. Our data, moreover, suggest that treatment efficacy is positively correlated with the total number of laser treatments.

[Palliative therapy concepts for pancreatic carcinoma]. / Palliative Konzepte beim Pankreaskarzinom.

The majority of patients with ductal pancreatic adenocarcinoma are already in a locally advanced or metastatic stage at the time of diagnosis and require palliative therapy. Interventional and operative measures are available for the restoration of biliary outflow in bile duct obstruction and the continuity of the upper intestinal lumen in duodenal or gastric outlet obstruction. In the presence of tumor-related pain, pain therapy according to the World Health Organization (WHO) scheme or a truncus coeliacus blockade, in cachexia a nutritional therapy and in thromboembolic events an anticoagulant therapy are used. An individualized palliative chemotherapy regimen should be selected for each patient, taking into account the patient's general condition and the side effects profile of the chemotherapeutic agents. Radiochemotherapy and local ablative therapies should currently only be used within the framework of studies. A palliative resection is not recommended according to current knowledge.

A robust viologen and Mn-based porous coordination polymer with two types of Lewis acid sites providing high affinity for H2O, CO2 and NH3.

A novel porous coordination polymer [Mn(pc3)(H2O)2]·xH2O (3 < x < 4) is synthesized in water at pH = 7 using the anionic viologen-carboxylate ligand 4,4'-bipyridinium,1,1'-bis-(2,4-dicarboxyphenyl) (pc32-). Dehydration of the material results in the formation of open pores containing two types of accessible Lewis acid sites: exposed Mn2+ cations and N+ atoms of viologen units. Due to this property the PCP shows high affinity and capacity in the adsorption of H2O, CO2 and NH3. Despite the presence of strong adsorption sites this material is stable in liquid water and in gaseous NH3.

[Branch duct intraductal papillary mucinous neoplasm - contra resection]. / Intraduktale papillär-muzinöse Neoplasie des Seitengangs­ Kontra Resektion.

Due to improvements in imaging modalities the diagnosis of branch duct intraductal papillary mucinous neoplasms (BD-IPMN) has been significantly increased in recent years. A BD-IPMN is frequently diagnosed as an incidental finding in asymptomatic patients. The optimal management of BD-IPMN is the subject of controversial discussions. Numerous studies have shown that an individualized therapeutic strategy with a follow-up observation of most BD-IPMNs is feasible and safe, considering age, comorbidities and patient preference. An accurate evaluation of BD-IPMN with a detailed anamnesis, high-resolution imaging techniques and endoscopic ultrasound is necessary. Symptomatic patients as well as patients with so-called high-risk stigmata should undergo resection. Asymptomatic patients with so-called worrisome features can either undergo surveillance or surgical resection, taking age and comorbidities into account. For BD-IPMN patients without high-risk stigmata and worrisome features and showing no symptoms, surveillance of the pancreatic lesion is the preferred approach. The high prevalence of BD-IPMN, limitations in differential diagnostics, an overestimation of the risk of malignancy due to an overrepresentation of symptomatic and suspected BD-IPMN in resected cohorts, an overestimated role of BD-IPMN as precursor lesions for pancreatic carcinoma and evidence of the safety of follow-up surveillance, underline the enormous importance of surveillance. Based on this and considering the background of a notable mortality and morbidity of pancreatic surgery, aggressive management with prophylactic surgical resection is not justified for all BD-IPMN, in particular for low-risk lesions.

Towards objective hand hygiene technique assessment: validation of the ultraviolet-dye-based hand-rubbing quality assessment procedure.

Ultraviolet spectrum markers are widely used for hand hygiene quality assessment, although their microbiological validation has not been established. A microbiology-based assessment of the procedure was conducted. Twenty-five artificial hand models underwent initial full contamination, then disinfection with UV-dyed hand-rub solution, digital imaging under UV-light, microbiological sampling and cultivation, and digital imaging of the cultivated flora were performed. Paired images of each hand model were registered by a software tool, then the UV-marked regions were compared with the pathogen-free sites pixel by pixel. Statistical evaluation revealed that the method indicates correctly disinfected areas with 95.05% sensitivity and 98.01% specificity.

[R1 resection for pancreatic carcinoma]. / R1-Resektion beim Pankreaskarzinom.

BACKGROUND: Surgery is the only potentially curative therapeutic approach in patients with pancreatic ductal adenocarcinoma (PDAC); however, achieving a negative (R0) resection margin is not always possible. OBJECTIVE: The impact of R1 resection margins on survival rates and treatment options (surgical and multimodal) for intraoperatively and postoperatively identified R1 resection margins. RESULTS: For intraoperatively diagnosed R1 resection margins, a re-resection (e.g. pancreas, main bile duct, stomach, superior mesenteric and portal vein) can be performed to achieve R0 resection margins. Arterial resections and the resection of additional organs are occasionally technically feasible and can be performed in an individual approach. New neoadjuvant and adjuvant treatment strategies have increased the rate of resectable PDAC and have improved the outcome of patients with R0/R1 resected PDACs. CONCLUSION: An R0 resection is the primary goal of surgery in patients with PDAC as R1 resections are correlated with a poor outcome.

Genetic and epigenetic alterations in the GNAS locus and clinical consequences in Pseudohypoparathyroidism: Italian common healthcare pathways adoption.

BACKGROUND: Genetic and epigenetic alterations in the GNAS locus are responsible for the Gsα protein dysfunctions causing Pseudohypoparathyroidism (PHP) type Ia/c and Ib, respectively. For these heterogeneous diseases characterized by multiple hormone resistances and Albright's Hereditary Osteodystrophy (AHO) the current classification results inadequate because of the clinical overlap between molecular subtypes and a standard clinical approach is still missing. In the present paper several members of the Study Group Endocrine diseases due to altered function of Gsα protein of the Italian Society of Pediatric Endocrinology and Diabetology (ISPED) have reviewed and updated the clinical-molecular data of the largest case series of (epi)/genetically characterized AHO/PHP patients; they then produced a common healthcare pathway for patients with these disorders. METHODS: The molecular analysis of the GNAS gene and locus identified the causal alteration in 74 subjects (46 genetic and 28 epigenetic mutations). The clinical data at the diagnosis and their evolution during up to 15 years follow-up were collected using two different cards. RESULTS: In patients with genetic mutations the growth impairment worsen during the time, while obesity prevalence decreases; subcutaneous ossifications seem specific for this group. Brachydactyly has been detected in half of the subjects with epigenetic alterations, in which the disease overts later in life, often with symptomatic hypocalcaemia, and also early TSH and GHRH resistances have been recorded. CONCLUSIONS: A dedicated healthcare pathway addressing all these aspects in a systematic way would improve the clinical management, allowing an earlier recognition of some PHP features, the optimization of their medical treatment and a better clinical-oriented molecular analysis. Furthermore, standardized follow-up data would provide new insight into less known aspects.

CdTe Timepix detectors for single-photon spectroscopy and linear polarimetry of high-flux hard x-ray radiation.

Single-photon spectroscopy of pulsed, high-intensity sources of hard X-rays - such as laser-generated plasmas - is often hampered by the pileup of several photons absorbed by the unsegmented, large-volume sensors routinely used for the detection of high-energy radiation. Detectors based on the Timepix chip, with a segmentation pitch of 55 µm and the possibility to be equipped with high-Z sensor chips, constitute an attractive alternative to commonly used passive solutions such as image plates. In this report, we present energy calibration and characterization measurements of such devices. The achievable energy resolution is comparable to that of scintillators for γ spectroscopy. Moreover, we also introduce a simple two-detector Compton polarimeter setup with a polarimeter quality of (98 ± 1)%. Finally, a proof-of-principle polarimetry experiment is discussed, where we studied the linear polarization of bremsstrahlung emitted by a laser-driven plasma and found an indication of the X-ray polarization direction depending on the polarization state of the incident laser pulse.