Evolution of point defects in pulsed-laser-melted Ge1-xSnxprobed by positron annihilation lifetime spectroscopy.

Direct-band-gap Germanium-Tin alloys (Ge1-xSnx) with high carrier mobilities are promising materials for nano- and optoelectronics. The concentration of open volume defects in the alloy, such as Sn and Ge vacancies, influences the final device performance. In this article, we present an evaluation of the point defects in molecular-beam-epitaxy grown Ge1-xSnxfilms treated by post-growth nanosecond-range pulsed laser melting (PLM). Doppler broadening - variable energy positron annihilation spectroscopy and variable energy positron annihilation lifetime spectroscopy are used to investigate the defect nanostructure in the Ge1-xSnxfilms exposed to increasing laser energy density. The experimental results, supported with ATomic SUPerposition calculations, evidence that after PLM, the average size of the open volume defects increases, which represents a raise in concentration of vacancy agglomerations, but the overall defect density is reduced as a function of the PLM fluence. At the same time, the positron annihilation spectroscopy analysis provides information about dislocations and Ge vacancies decorated by Sn atoms. Moreover, it is shown that the PLM reduces the strain in the layer, while dislocations are responsible for trapping of Sn and formation of small Sn-rich-clusters.

Band-gap and strain engineering in GeSn alloys using post-growth pulsed laser melting.

The pseudomorphic growth of Ge1-xSnxon Ge causes in-plane compressive strain, which degrades the superior properties of the Ge1-xSnxalloys. Therefore, efficient strain engineering is required. In this article, we present strain and band-gap engineering in Ge1-xSnxalloys grown on Ge a virtual substrate using post-growth nanosecond pulsed laser melting (PLM). Micro-Raman and x-ray diffraction (XRD) show that the initial in-plane compressive strain is removed. Moreover, for PLM energy densities higher than 0.5 J cm-2, the Ge0.89Sn0.11layer becomes tensile strained. Simultaneously, as revealed by Rutherford Backscattering spectrometry, cross-sectional transmission electron microscopy investigations and XRD the crystalline quality and Sn-distribution in PLM-treated Ge0.89Sn0.11layers are only slightly affected. Additionally, the change of the band structure after PLM is confirmed by low-temperature photoreflectance measurements. The presented results prove that post-growth ns-range PLM is an effective way for band-gap and strain engineering in highly-mismatched alloys.

Field-resolved THz-pump laser-probe measurements with CEP-unstable THz light sources.

Radiation sources with a stable carrier-envelope phase (CEP) are highly demanded tools for field-resolved studies of light-matter interaction, providing access both to the amplitude and phase information of dynamical processes. At the same time, many coherent light sources, including those with outstanding power and spectral characteristics lack CEP stability, and so far could not be used for this type of research. In this work, we present a method enabling linear and non-linear phase-resolved terahertz (THz) -pump laser-probe experiments with CEP-unstable THz sources. THz CEP information for each pulse is extracted using a specially designed electro-optical detection scheme. The method correlates the extracted CEP value for each pulse with the THz-induced response in the parallel pump-probe experiment to obtain an absolute phase-resolved response after proper sorting and averaging. As a proof-of-concept, we demonstrate experimentally field-resolved THz time-domain spectroscopy with sub-cycle temporal resolution using the pulsed radiation of a CEP-unstable infrared free-electron laser (IR-FEL) operating at 13 MHz repetition rate. In spite of the long history of IR-FELs and their unique operational characteristics, no successful realization of CEP-stable operation has been demonstrated yet. Being CEP-unstable, IR-FEL radiation has so far only been used in non-coherent measurements without phase resolution. The technique demonstrated here is robust, operates easily at high-repetition rates and for short THz pulses, and enables common sequential field-resolved time-domain experiments. The implementation of such a technique at IR-FEL user end-stations will facilitate a new class of linear and non-linear experiments for studying coherent light-driven phenomena with increased signal-to-noise ratio.

Internalized skin bias: validation study to explore the impact of the internalization of social stigma on those with hidradenitis suppurativa.

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic auto-inflammatory disease that is highly associated with adverse psychopathology and impaired body image. Previous studies show that patients with HS are also impacted by social stigma associated with their skin disease. Over time, these experiences can influence the way in which patients feel about themselves, leading to internalized skin bias (ISB). OBJECTIVES: To evaluate the validity and reliability of the Internalized Skin Bias Questionnaire (ISBQ) in an HS population and to determine the association of this instrument with markers of HS severity. METHODS: A cross-sectional survey with 72-h retest was sent to adult patients with HS from March to November 2021. Reliability for the ISBQ was evaluated using Cronbach's alpha and the Concordance Correlation Coefficient (CCC). Construct validity was evaluated using Pearson Correlation Coefficients with similar measures. RESULTS: Internal consistency for the ISBQ instrument was 0.89 with a CCC of 0.88. The ISBQ had moderate correlation (r = 0.63) with the experienced skin stigma questionnaire as well as the BDI-II (r = 0.66) and the psychosocial subscale of the HiSQOL (r = 0.65). ISBQ scores differed significantly across different stages of disease severity (P = 0.04). There was no significant difference between those with different durations of disease (P = 0.47). CONCLUSIONS: This study shows that the ISBQ is a valid and reliable instrument that can be used to assess the psychosocial construct of ISB especially in a population of HS patients. Further, ISB places a prevalent negative impact on the psychopathology of patients with HS.

[Hypoxic and hypoglycemic brain damage as a result of an adrenal cortex crisis-An important differential diagnosis in cases of unspecific symptoms]. / Hypoxisch-hypoglykämischer Hirnschaden infolge einer Nebennierenrindenkrise ­ eine wichtige Differenzialdiagnose bei unspezifischer Symptomatik.

Acute adrenal cortex insufficiency is a rare disease, which is hard to diagnose because of its diffuse symptoms. Symptoms, such as general weakness, nausea or vomiting, fatigue, hyponatremia, hyperkalemia, hypoglycemia and pronounced hypotension up to shock can be crucial in the diagnosis of an adrenal cortex crisis. The underlying disease of adrenal cortex insufficiency is also characterized by not always obvious symptoms, which are differently expressed depending on whether it is the primary or secondary type.After the diagnosis is made it is important to educate the patients, determine the optimal dosage of the substitution and ensure the compliance of the patients to optimize the further process and avoid an adrenal crisis. An adrenal crisis is one of the reasons for a higher mortality of these patients, which is well-described in the current literature. Descriptions of fatal courses and their reasons are rare; however, knowledge of the disease and the importance of rapid intervention is very important, especially for physicians who work in the emergency room or intensive care unit (ICU).This article reports about a female patient with a known secondary adrenal cortex insufficiency who developed the complete picture of an adrenal crisis. Despite rapid diagnosis and initiation of treatment massive brain damage could not be averted due to hypoxia and hypoglycemia. This case report demonstrates the potential symptoms, in particular a massive hypoglycemia and an initial shock refractory to catecholamine. It also shows the severity of that disease and the importance of rapid treatment even though it is difficult to make the diagnosis.

Vascular malformations of the female and male genitalia: type and distribution patterns revealed by magnetic resonance imaging.

BACKGROUND: Vascular malformations of the genitalia often go undetected in clinical examination. These vascular malformations can cause a variety of clinical symptoms such as swelling, pain and bleeding. AIM: To characterize the distribution patterns of genital vascular malformations using magnetic resonance imaging (MRI) and to correlate these patterns with clinical findings in order to guide diagnostic decisions. METHODS: A retrospective analysis of MRIs of the pelvis and legs in 370 patients with vascular malformation was performed to determine the involvement of the internal and external genitalia. RESULTS: In 71 patients (19%), genital involvement could be identified by MRI. Of these, 11.3% (8 of 71) presented with internal involvement, 36.6% (26 of 71) with external involvement and 52.1% (37 of 71) with both internal and external involvement. Over half (57.1%) of the 49 patients with visible external genital signs detected during a clinical examination had additional internal genital involvement. CONCLUSIONS: Genital involvement is a common finding in patients with vascular malformation of the legs and/or pelvis. Based on our data, we recommend MRI of the legs and pelvic region in patients with externally visible signs of a vascular malformation of the external genitalia in order to exclude additional internal involvement.

Isolation of primary human B lymphocytes from tonsils compared to blood as alternative source for ex vivo application.

B lymphocytes ('B cells') are components of the human immune system with obvious potential for medical and biotechnological applications. Here, we discuss the isolation of primary human B cells from both juvenile and adult tonsillar material using a two-step procedure based on gradient centrifugation followed by separation on a nylon wool column as alternative to the current gold standard, i.e., negative immunosorting from buffy coats by antibody-coated magnetic beads. We show that the nylon wool separation is a low-cost method well suited to the isolation of large amounts of primary B cells reaching purities ≥ 80%. More importantly, this method allows the preservation of all B cell subsets, while MACS sorting seems to be biased against a certain B cell subtype, namely the CD27+ B cells. Importantly, compared to blood, the excellent recovery yield during purification of tonsillar B cells provides high number of cells, hence increases the number of subsequent experiments feasible with identical cell material, consequently improving comparability of results. The cultivability of the isolated B cells was demonstrated using pokeweed mitogen (PWM) as a stimulatory substance. Our results showed for the first time that the proliferative response of tonsillar B cells to mitogens declines with the age of the donor. Furthermore, we observed that PWM treatment stimulates the proliferation of a dedicated subpopulation and induces some terminal differentiation with ASCs signatures. Taken together this indicates that the proposed isolation procedure preserves the proliferative capability as well as the differentiation capacity of the B cells.

Time Refraction of Spin Waves.

We present an experimental study of time refraction of spin waves (SWs) propagating in microscopic waveguides under the influence of time-varying magnetic fields. Using space- and time-resolved Brillouin light scattering microscopy, we demonstrate that the broken translational symmetry along the time coordinate results in a loss of energy conservation for SWs and thus allows for a broadband and controllable shift of the SW frequency. With an integrated design of SW waveguide and microscopic current line for the generation of strong, nanosecond-long, magnetic field pulses, a conversion efficiency up to 39% of the carrier SW frequency is achieved, significantly larger compared to photonic systems. Given the strength of the magnetic field pulses and its strong impact on the SW dispersion relation, the effect of time refraction can be quantified on a length scale comparable to the SW wavelength. Furthermore, we utilize time refraction to excite SW bursts with pulse durations in the nanosecond range and a frequency shift depending on the pulse polarity.

Concern about malignancy contributes to the psychosocial toll of dermatomyositis.

Objective: Dermatomyositis (DM) is associated with increased morbidity and mortality, decreased quality of life, and an increased incidence of psychiatric illness. We performed a pilot study to investigate whether concern about malignancy contributes to the psychosocial toll of DM.Method: Patients with a recent DM diagnosis at our institution between 2013 and 2018 and no history of DM-associated malignancy completed standardized questionnaires and a novel survey generated by our group, and participated in focus groups.Results: Seventeen patients (14 females and three males) completed the surveys. The mean Dermatology Life Quality Index (DLQI) score was 2.75. The mean score on the Patient Health Questionnaire-9 (PHQ-9) was 5.35, with a range of 0-20. Our independent DM-specific questionnaire revealed a mean of 17.41 (range 2-40).Conclusion: Concern about the increased risk of malignancy contributes to the psychosocial toll of DM. Individual impacts are highly variable and patient specific. Clinicians should assess for depression and anxiety in patients with DM, understanding that concern for malignancy adds to the total psychosocial burden in some patients.

Symptomatic rebound methaemoglobinaemia after treatment with dapsone.

A 28-year-old female patient was admitted to our hospital with severe dyspnoea and hypoxemia due to methaemoglobinaemia caused by dapsone. The patient recovered completely after repeated infusions of methylene blue and cessation of dapsone. However, 12 days after cessation of dapsone, the patient was readmitted due to recurrence of symptoms based on a relapse of methaemoglobinaemia. Toxicological analysis revealed a toxic dapsone level at readmission and no other explanation for methaemoglobinaemia. Several possible mechanisms as explanation for the recurrence of methaemoglobinaemia are listed and additional tests were performed. In addition to supportive care, treatment consisted of methylene blue; furthermore, cimetidine and ascorbic acid were added. An overview of the pathophysiology, diagnostics, treatment, and possible explanations for this relapse of methaemoglobinaemia caused by dapsone are given. This case shows the importance of considering the possibility of a late rebound methaemoglobinaemia after discontinuation of dapsone.

Multiplexed blood-brain barrier organ-on-chip.

Organ-on-chip devices are intensively studied in academia and industry due to their high potential in pharmaceutical and biomedical applications. However, most of the existing organ-on-chip models focus on proof of concept of individual functional units without the possibility of testing multiple experimental stimuli in parallel. Here we developed a polydimethylsiloxane (PDMS) multiplexed chip with eight parallel channels branching from a common access port through which all eight channels can be addressed simultaneously without the need for extra pipetting steps thus increasing the reproducibility of the experimental results. At the same time, eight outlets provide individual entry to each channel with the opportunity to create eight different experimental conditions. A multiplexed chip can be assembled as a one-layer device for studying monocultures or as a two-layer device for studying barrier tissue functions. For a two-layer device, a ∼2 µm thick transparent PDMS membrane with 5 µm through-hole pores was fabricated in-house using a soft lithography technique, thereby allowing visual inspection of the cell-culture in real-time. The functionality of the chip was studied by recapitulating the blood-brain barrier. For this, human cerebral microvascular endothelial cells (hCMEC/D3) were cultured in mono- or coculture with human astrocytes. Immunostaining revealed a cellular monolayer with the expression of tight junction ZO-1 and adherence junction VE-cadherin proteins in endothelial cells as well as glial fibrillary acidic protein (GFAP) expression in astrocytes. Furthermore, multiplexed permeability studies of molecule passage through the cellular barrier exhibited expected high permeability coefficients for smaller molecules (4 kDa FITC-dextran) whereas larger molecules (20 kDa) crossed the barrier at a lower rate. With these results, we show that our device can be used as an organ-on-chip model for future multiplexed drug testing.

Exercise and insulin resistance in PCOS: muscle insulin signalling and fibrosis.

OBJECTIVE: Mechanisms of insulin resistance in polycystic ovary syndrome (PCOS) remain ill defined, contributing to sub-optimal therapies. Recognising skeletal muscle plays a key role in glucose homeostasis we investigated early insulin signalling, its association with aberrant transforming growth factor ß (TGFß)-regulated tissue fibrosis. We also explored the impact of aerobic exercise on these molecular pathways. METHODS: A secondary analysis from a cross-sectional study was undertaken in women with (n = 30) or without (n = 29) PCOS across lean and overweight BMIs. A subset of participants with (n = 8) or without (n = 8) PCOS who were overweight completed 12 weeks of aerobic exercise training. Muscle was sampled before and 30 min into a euglycaemic-hyperinsulinaemic clamp pre and post training. RESULTS: We found reduced signalling in PCOS of mechanistic target of rapamycin (mTOR). Exercise training augmented but did not completely rescue this signalling defect in women with PCOS. Genes in the TGFß signalling network were upregulated in skeletal muscle in the overweight women with PCOS but were unresponsive to exercise training except for genes encoding LOX, collagen 1 and 3. CONCLUSIONS: We provide new insights into defects in early insulin signalling, tissue fibrosis, and hyperandrogenism in PCOS-specific insulin resistance in lean and overweight women. PCOS-specific insulin signalling defects were isolated to mTOR, while gene expression implicated TGFß ligand regulating a fibrosis in the PCOS-obesity synergy in insulin resistance and altered responses to exercise. Interestingly, there was little evidence for hyperandrogenism as a mechanism for insulin resistance.

Women's perspectives of early menopause: development of a word cloud.

Objective: Early menopause (EM), menopause aged <45 years, occurs spontaneously or secondary to medical treatments and is associated with multiple health impacts. A word cloud is an image where the word size reflects the frequency of use. We aimed to assess the perspectives of women with EM using a word cloud.Methods: Women diagnosed with EM, recruited from clinics/community, completed a survey including the open-ended question 'What words do you associate with EM?'. Demographics and medical history were collected. Data analysis included descriptive statistics, identification of word themes/stems/synonyms, word frequency, and chi-square test. A word cloud was constructed from words used by two or more women using 'Wordle' (www.wordle.net).Results: Responses were obtained from 190/263 participants. The mean age was 54 ± 11 years, with EM diagnosed at age 38 ± 5 years. The cause of EM was unknown (30% of women), bilateral oophorectomy (27%), cancer therapy (25%), or autoimmune/genetic/metabolic (17%). The commonest words reported were hot flushes (36.8% of women), mood swings (20.5%), and infertility (16.8%), which varied with age and cause of EM. Few women reported neutral/positive words.Conclusion: Most words that women associate with EM have negative connotations and refer to symptoms. A word cloud is a novel way to illustrate women's perspectives.

[Analgesia for trauma patients in emergency medicine]. / Analgesie bei Traumapatienten in der Notfallmedizin.

Adequate analgesia is one of the most important measures of emergency care in addition to treatment of vital function disorders and, if indicated, should be promptly undertaken; however, a large proportion of emergency patients receive no or only inadequate pain therapy. The numeric rating scale (NRS) is recommended for pain assessment but is not applicable to every group of patients; therefore, vital signs and body language should be included in the assessment. Pain therapy should reduce the NPRS to <5 points. Ketamine and fentanyl, which have an especially rapid onset of action, and also morphine are suitable for analgesia in spontaneously breathing patients. Basic prerequisites for safe and effective analgesia by healthcare professionals are the use of adequate monitoring, the provision of well-defined emergency equipment, and the mastery of emergency procedures. In a structured competence system, paramedics and nursing personnel can perform safe and effective analgesia.

Blood transfusions increase the risk of venous thromboembolism following ventral hernia repair.

BACKGROUND: Blood transfusions can affect the clotting cascade, leading to a hypercoagulable state. The association of a venous thromboembolic (VTE) event and perioperative blood transfusion has been identified previously in surgical patients, but not after ventral hernia repair (VHR). The aim of this study was to evaluate the risk of VTE in VHR patients who receive a perioperative blood transfusion. METHODS: The American College of Surgeons National Surgery Quality Improvement Program was queried for open (n = 34,687) and laparoscopic (n = 11,544) VHRs that occurred from 2013 to 2015. Regression analyses were used to determine factors predictive of VTE within 30-day post-operatively, the impact of bleeding requiring blood transfusion, and the influence of surgical approach on VTE. RESULTS: Post-operative VTE occurred in 246 (0.5%) VHR patients. Among those patients, 53.0% occurred after discharge. Increased age, operative time, and comorbidities increased the risk of VTE (p < 0.05). Controlling for surgical approach, perioperative blood transfusion increased the risk of VTE 10.2-fold (p < 0.0001) in open and 12.2-fold in laparoscopic VHR (p < 0.0001). CONCLUSION: Perioperative blood transfusions are associated with an increased rate of VTE following VHR, more than 50% of which occur after discharge. This study highlights the importance of identifying quality initiatives for at risk patients, including adequate VTE screening and potential prophylaxis for those who receive perioperative blood transfusions.

In-vitro study of species-specific coagulation differences in animals and humans using rotational thromboelastometry (ROTEM).

Animal tests are conducted in all fields of trauma research, but transferability of these data to humans is limited. For example, it is still unclear which animal species is most similar to humans in terms of physiology of blood coagulation. To improve transferability and raise awareness of the existing differences, we compared human coagulation to coagulation of different animals. Rotational thromboelastometry was used to analyse the blood of pigs, sheep, rabbits and dogs. Animal data were compared with human coagulation based on the number of significant differences of the test parameters and on a descriptive comparison of the extent of relative deviation of the single values. All animal species showed significant differences in coagulation properties when compared with humans. Coagulation parameters of dogs and sheep were on average most similar to humans. However, there is no animal which is most similar to humans concerning all aspects of coagulation. Differences in coagulation between humans and animals are significant. This must be taken into account when transferring animal test data to humans.

Comparative study of equivalent circuit models for photoconductive antennas.

Comparison of equivalent circuit models (ECM) for photoconductive antennas (PCA) represents a challenge due to the multiphysics phenomena involved during PCA operation and the absence of a standardized validation methodology. In this work, currently reported ECMs are compared using a unique set of simulation parameters and validation indicators (THz waveform, optical power saturation, and ECM voltages consistency). The ECM simulations are contrasted with measured THz pulses of an H-shaped 20µm gap PCA at different optical powers (20mW to 220mW). In addition, an alternative two-element ECM that accounts for both space-charge and radiation screening effects is presented and validated using the proposed methodology. The model shows an accurately reproduced THz pulse using a reduced number of circuital elements, which represents an advantage for PCA modeling.

Structured analysis, evaluation and report of the emergency response to a terrorist attack in Wuerzburg, Germany using a new template of standardised quality indicators.

BACKGROUND: Until now there has been a reported lack of systematic reports and scientific evaluations of rescue missions during terror attacks. This however is urgently required in order to improve the performance of emergency medical services and to be able to compare different missions with each other. Aim of the presented work was to report the systematic evaluation and the lessons learned from the response to a terror attack that happened in Wuerzburg, Germany in 2016. METHODS: A team of 14 experts developed a template of quality indicators and operational characteristics, which allow for the description, assessment and comparison of civil emergency rescue missions during mass killing incidents. The entire systematic evaluation process consisted of three main steps. The first step was the systematic data collection according to the quality indicators and operational characteristics. Second was the systematic stratification and assessment of the data. The last step was the prioritisation of the identified weaknesses and the definition of the lessons learned. RESULTS: Five important "lessons learned" have been defined. First of all, a comprehensive concept for rescue missions during terror attacks is essential. Furthermore, the establishment of a defined high priority communication infrastructure between the different dispatch centres ("red phone") is vital. The goal is to secure the continuity of information between a few well-defined individuals. Thirdly, the organization of the incident scene needs to be commonly decided and communicated between police, medical services and fire services during the mission. A successful mission tactic requires continuous flux of reports to the on-site command post. Therefore, a predefined and common communication infrastructure for all operational forces is a crucial point. Finally, all strategies need to be extensively trained before the real life scenario hits. CONCLUSION: According to a systematic evaluation, we defined the lessons learned from a terror attack in 2016. Further systematic reports and academic work surrounding life threatening rescue missions and mass killing incidents are needed in order to ultimately improve such mission outcomes. In the future, a close international collaboration might help to find the best database to report and evaluate major incidents but also mass killing events.