Consideration of Statistical Approaches Within the Accelerated Assessment of Fatigue Properties of Metallic Materials

Understanding the fatigue behaviour of metallic materials is highly important when it comes to a reliable assessment of material degradation as a result of dynamic loading. Because the provision of such data is associated with great testing effort leading to increased time and cost requirements in terms of conventional methods, accelerated lifetime prediction methods are becoming increasingly important. However, the reduced number of fatigue specimens and tests complicates statistical validations of the obtained results. In this contribution, combinatorial approaches are used to estimate both lifetime prediction bands and virtually-determined S-N curves with a reduced number of specimens, displaying the material-related scatter due to microstructural inhomogeneities. In addition, a variable energy dissipation factor based on cyclic deformation curves is presented, which enables evaluation of materials that exhibit more pronounced scatter, for instance cast materials. An in situ evaluation of the cyclic deformation curves is provided via integration of non-destructive testing methods into the testing rig. Unalloyed SAE 1045 steel, low-alloyed 20MnMoNi5-5 steel, and the cast material EN-GJS-1050-6 are investigated in this research, as these materials posses gradually increasing complexity regarding their respective microstructures

Valorizing Organic Waste: Selenium Sulfide Production Mediated by Sulfate-Reducing Bacteria

Selenium sulfide, the active ingredient of traditional antidandruff shampoos, is industrially produced from selenium dioxide (SeO2) and hydrogen sulfide (H2S) under acidic conditions. This reaction can also be carried out with natural H2S and H2S generated by sulfate-reducing bacteria (SRB). These bacteria are robust and, by relying on their conventional growth medium, also thrive in “waste” materials, such as a mixture of cabbage juice and compost on the one side, and a mixture of spoiled milk and mineral water on the other. In these mixtures, SRB are able to utilize the DL-lactate and sulfate (SO4 2−) present naturally and produce up to 4.1 mM concentrations of H2S in the gas phase above a standard culture medium. This gas subsequently escapes the fermentation vessel and can be collected and reacted with SeO2 in a separate compartment, where it yields, for instance, pure selenium sulfide, therefore avoiding the need for any cumbersome workup or purification procedures. Thus “harvesting” H2S and similar (bio-)gases produced by the fermentation of organic waste materials by suitable microorganisms provides an elegant avenue to turn dirty waste into valuable clean chemical products of considerable industrial and pharmaceutical interest

Femtosecond Laser-Assisted Donor and Recipient Preparation for Bowman Layer Transplantation

Objectives: A Ziemer LDV Z8 femtosecond laser (FSL) was used to obtain optimal cutting parameters with precise settings for donor and recipient preparations for Bowman layer transplantation. Methods: Of 48 human research corneas examined, 32 were used for Bowman layer preparation (donor) and 16 for pocket preparation (recipient) using the LDV Z8 FSL. The cutting thickness of the Bowman layer, pocket depth, and corresponding laser settings were varied. The quality of sections was evaluated based on the occurrence of adhesions, bridges, or perforations. Histological specimens were prepared and analyzed. Results: Preparation of the Bowman layer and recipient pocket was possible using all selected settings. The thinner the Bowman layer and the more superficial the pocket preparation, the higher the risk of perforation was. Considering the fact that the Bowman layer was cut as thinly as possible, a Bowman layer thickness of 30 µm showed a 100% success rate. Bowman layers cut at 25 µm had a lower success rate (50%). The pocket depth of 150 µm showed a 100% success rate in the preparation. Histological processing revealed smooth, precisely cut edges of Bowman layers and pockets. Implantation into the pocket was successful in all cases. Conclusions: Both Bowman layer and pocket preparation were technically and surgically feasible using the LDV Z8 FSL, and the prepared Bowman layers were thinner than those reported in previous studies. The optimal Bowman layer thickness was 30 µm, and a resection depth of 150 µm was used to prepare the pockets safely

Triangular Screw Placement to Treat Dysmorphic Sacral Fragility Fractures in Osteoporotic Bone Results in an Equivalent Stability to Cement-Augmented Sacroiliac Screws—A Biomechanical Cadaver Study

Background: Sacroiliac screw fixation in elderly patients with pelvic fractures remains a challenging procedure for stabilization due to impaired bone quality. To improve it, we investigated the biomechanical properties of combined oblique sacroiliac and transiliosacral screw stabilization versus the additional cement augmentation of this construct in a cadaver model of osteoporotic bone, specifically with respect to the maximal force stability and fracture-site motion in the displacement and rotation of fragments. Methods: Standardized complete sacral fractures with intact posterior ligaments were created in osteoporotic cadaver pelvises and stabilized with a triangle of two oblique sacroiliac screws from each side with an additional transiliosacral screw in S1 (n = 5) and using the same pelvises with additional cement augmentation (n = 5). A short cyclic loading protocol was applied, increasing the axial force up to 125 N. Sacral fracture-site motion in displacement and rotation of the fragments was measured by optical motion tracking. Results: A maximum force of 65N +/− 12.2 N was achieved using the triangular screw stabilization of the sacrum. Cement augmentation did not provide any significant gain in maximum force (70 N +/− 29.2 N). Only low fragment displacement was observed (2.6 +/− 1.5 mm) and fragment rotation (1.3 +/− 1.2◦ ) without increased stability (3.0 +/− 1.5 mm; p = 0.799; 1.7 +/− 0.4◦ ; p = 0.919) following the cement augmentation. Conclusions: Triangular stabilization using two obliques and an additional transiliosacral screw provides sufficient primary stability of the sacrum. Still, the stability achieved seems very low, considering the forces acting in this area. However, additional cement augmentation did not increase the stability of the sacrum. Given its lack of beneficial abilities, it should be used carefully, due to related complications such as cement leakage or nerve irritation. Improving the surgical methods used to stabilize the posterior pelvic ring will be a topic for future research

Adult ADHD predicts intimate partner violence perpetration and victimization irrespective of gender and age

Understanding the determinants of intimate partner violence (IPV) from perpetrator and victim perspectives has become a major objective of behavioral science. Empirical evidence suggests that adults at risk for Attention-Deficit/Hyperactivity Disorder (ADHD), compared to the general population, tend to have more conflictual partnerships, and the presence of ADHD increases the risk of aggressive behavior. Possible influences of gender have not been sufficiently investigated yet. Using data from an anonymous online survey, this study examined the relationship between ADHD and IPV in 316 male and female individuals with (n = 131) and without (n = 185) ADHD. Multiple linear regression analyses showed that adults at risk for ADHD had more frequently become both victims and perpetrators of IPV compared to the healthy control group. ADHD achieved significant incremental variance over gender and age. Thus, the presence of ADHD seems to be an important risk factor for IPV irrespective of gender and age. Accordingly, research and treatment approaches focusing on ADHD must not neglect the risk of IPV among patients but should offer specific psychological support

Lutembacher syndrome with congenital atrial septal defect in an 18-year-old female: a rare case report

Introduction: Lutembacher syndrome (LS) is a rare condition with congenital atrial septal defect (ASD) and mitral stenosis (MS), often post-rheumatic illness. Diagnosis uses Doppler echocardiography, and treatment may involve surgery or percutaneous options. Case presentation: An 18-year-old female presented with worsening dyspnea, orthopnea, and potential undiagnosed rheumatic fever. Chest X-ray showed cardiomegaly. An echocardiogram revealed left atrial dilation and mitral stenosis with regurgitation, aortic valve showed thickening without stenosis, and the right ventricle was mildly dilated; an interatrial shunt was present. Mitral stenosis worsened left-to-right shunt. Discussion: LS results from the balance of ASD and MS. Factors influencing prognosis include pulmonary resistance, ASD size, and mitral stenosis severity. Echocardiography is essential for diagnosis, which revealed left atrial dilation, normal left ventricular function, severe mitral stenosis, and pulmonary valve changes. ECG indicated right ventricular hypertrophy. CXR showed left atrial enlargement and right ventricle enlargement. Treatment included an open heart surgery which replaced the mitral valve and closed the ASD. Conclusion: Lutembacher syndrome, a rare condition combining ASD and mitral stenosis, can cause cardiac failure and pulmonary hypertension if untreated. Given the patient’s stable condition in the early stages of the disease, early surgical or percutaneous intervention is advisable

Impact of modifications on the characteristics of salivary pellicle on dental hard tissue: a scoping review

Objectives The salivary pellicle regulates interfacial events on dental surfaces and is a promising target for modification to improve dental health. This scoping review systematically examines substances that modify the pellicle, evaluating their potential and identifying knowledge gaps. Data This review followed the PRISMA-ScR guidelines. Studies investigating how substances applied during pellicle formation on enamel or dentin affect its structure, composition, or protective function were included. Sources A systematic search of Medline was conducted up to March 2024 using predefined terms. Only English-language research articles were included. No hand-searching was performed. Study selection A total of 864 records were identified. After title and abstract screening, 110 articles were assessed in full, resulting in 85 eligible studies for data charting. These studies investigated human saliva-derived pellicles on enamel or dentin, comparing their composition, structure, or protective properties with and without modification. Most studies, conducted equally in vitro and in situ, focused on fluorides and metals (n = 28), peptides and proteins (n = 21), and polyphenols (n = 18), while other substances were less frequently examined (n = 17). Modifications affected the pellicle’s ultrastructure, altered its proteome, or enhanced its protective role against erosion, abrasion, and bacterial adherence. Conclusions Despite numerous studies and distinct substance classes, findings remain inconclusive and must be interpreted within the context of individual study designs. Clinical significance Modifying the pellicle can improve its protective function, presenting a promising approach for preventive dentistry. However, the long-term effects of these substances within the dynamic oral environment remain unclear. This review underscores the need for further research to close existing knowledge gaps and confirm clinical relevance

The Chalcogen Exchange: The Replacement of Oxygen with Sulfur and Selenium to Boost the Activity of Natural Products

Antioxidants, such as stilbenes, anthocyanidins, coumarins, tannins and flavonoids, are often based on oxygen-containing redox systems and tend to feature several hydroxyl groups in their chemical structures. From a synthetic perspective, oxygen atoms are prone to bioisosteric replacement with sulfur and, notably, selenium. The main objective of this narrative literature review is to explore if and how bioisosteric substitution of oxygen with sulfur or selenium can enhance the biological activity of natural products. This re placement boosts the biological activity of the resulting molecules considerably as they now combine the redox and antioxidant properties of the original flavonoids and other natural products with the specific redox behavior of sulfur and selenium. Besides sequestering free radicals and peroxides, they may, for instance, also catalyze the removal of oxidative stressors, capture free metal ions and even provide scope for selenium supplementation. Since these molecules resemble their natural counterparts, they also exhibit considerable selectivity inside the body and a good pharmacokinetic profile. Still, the synthesis of such hybrid molecules integrating sulfur and selenium into flavonoids and other natural products is a challenge and requires innovative synthetic strategies and approaches

Modulating fear processes: Exploring the effects of intranasal insulin, glucose, and COVID-19 anxiety in classical fear conditioning

Anxiety disorders are among the most common mental illnesses world-wide and are of considerable public health importance due to their high prevalence (Wittchen et al., 2011). Despite the availability of effective treatments for anxiety disorders, millions of people suffer from symptoms that interfere with their daily lives, resulting in persistent distress and reduced overall quality of life (Craske et al., 2009). Within cognitive behavioral therapy, exposure therapy has been shown to be a successful treatment option for many anxiety disorders. Exposure involves systematically exposing patients to anxiety-provoking stimuli in a controlled and safe environment until the fear response diminishes. Despite its high efficacy, not all anxiety patients benefit equally from the therapy, and there are always dropouts, incomplete recovery, or relapse of symptoms (Arch & Craske, 2009). The development and treatment of anxiety disorders can be explained in part by processes of classical conditioning, in which neutral stimuli are given negative meanings through association learning (Duits et al., 2015). Classical models of fear conditioning help to understand the development, maintenance and treatment of anxiety disorders. At the same time, environmental factors, such as traumatic experiences or stressful life events, can play a central role in the development and progression of anxiety disorders. Stress can dysregulate neurobiological systems, particularly the limbic system and the amygdala, and thus increase vulnerability to the development of anxiety disorders (Garakani et al., 2006). Recent global events, such as the COVID-19 pandemic and other crises, may exacerbate these processes through chronic stress, leading to a further increase in the prevalence of anxiety disorders (Kazmi et al., 2020). It is essential to find ways to improve the treatment options for anxiety disorders, in particular to further improve exposure therapy. In addition to the use of classical psychotropic drugs, which are administered in addition to exposure therapy, the use of so-called cognitive enhancers, i.e. substances that influence neurocognitive processes such as attention, memory and learning, is proving to be promising. Studies have identified several such substances that have already shown positive effects in the context of fear extinction, including hormones such as oxytocin or cortisol (Brueckner et al., 2019; de Quervain et al., 2009; Eckstein et al., 2015, 2019). The aim of the present dissertation is to investigate the role of environmental stress and cognitive enhancers as modulating factors of fear conditioning processes. Several aims were pursued and a total of three empirical studies were conducted. The first study aimed to investigate the potential of intranasally administered insulin as a cognitive enhancer in the extinction of fear. To this end, a classical fear conditioning study was conducted with healthy subjects. Before extinction, the subjects were administered either insulin or a placebo by nasal spray. Subjects in the insulin group showed a greater reduction in the fear response during extinction, a first indication of the beneficial effect of intranasal insulin as a cognitive enhancer of fear extinction. The second study investigated the impact of anxiety related to the COVID-19 pandemic on fear learning and fear generalization. The aim was to investigate whether increased anxiety during COVID-19 can lead to increased conditionability and generalization of fear. To this end, a classical fear conditioning study was conducted with healthy subjects and COVID-19-related anxiety was measured. Subjects with higher COVID-19-related anxiety tended to discriminate poorly between safe and dangerous stimuli during fear learning and to generalize their fear response more strongly. Based on the results of the first study, the third study investigated whether the administration of glucose as a cognitive enhancer could improve the effects of fear extinction. Two fear conditioning studies were conducted in healthy subjects, in which the subjects were given either glucose or a placebo before (Study 1) or after (Study 2) extinction. Subjects in the glucose group showed a greater reduction in fear during extinction (Study 1) and during a later recall (Study 2), providing preliminary evidence for the efficacy of glucose as a cognitive enhancer in fear extinction. In conclusion, the three studies presented in this dissertation provide important insights for current research on fear extinction processes and their possible enhancement by cognitive enhancers such as insulin or glucose. Furthermore, the importance of environmental stressors in the development and maintenance of anxiety disorders is highlighted by the demonstrated influence of COVID-19-related anxiety on important fear learning processes such as fear generalization. By integrating the knowledge gained, the studies contribute to a better understanding of fear learning processes and lay the foundation for further research to gain practical implications for improving exposure therapy.Angststörungen zählen zu den häufigsten psychischen Erkrankungen weltweit und haben aufgrund der hohen Prävalenz eine erhebliche Bedeutung für die öffentliche Gesundheit (Wittchen et al., 2011). Obwohl es eine effektive Therapie gegen Angststörungen gibt, leiden Millionen von Menschen unter Symptomen, die das alltägliche Leben erschweren und so zu einer anhaltenden Belastung und Verringerung der allgemeinen Lebensqualität führen (Craske et al., 2009). In der kognitiven Verhaltenstherapie hat sich die Expositionstherapie als bewährte Therapieoption zur erfolgreichen Behandlung vieler Angststörungen erwiesen. Während der Exposition werden die PatientInnen systematisch mit den angstauslösenden Reizen in einer kontrollierten und sicheren Umgebung konfrontiert, bis die Angstreaktion abnimmt. Trotz hoher Effektivität, profitieren nicht alle AngstpatientInnen gleichermaßen von der Therapie und es kommt immer wieder zu Therapieabbrüchen, einer unvollständigen Genesung oder einem Rezidiv der Symptomatik (Arch & Craske, 2009). Die Entstehung und Behandlung von Angststörungen kann unter anderem durch Prozesse klassischer Konditionierung erklärt werden, bei denen neutralen Reizen durch Assoziationslernen eine negative Bedeutung zugeschrieben wird. Klassische Angstkonditionierungsmodelle helfen die Entstehung, Aufrechterhaltung und Behandlung von Angststörungen zu verstehen. Gleichzeitig können Umweltfaktoren, wie traumatische Erlebnisse oder stressige Lebensereignisse eine zentrale Rolle bei der Entstehung und dem Verlauf von Angststörungen spielen. Stress kann neurobiologische Systeme, insbesondere das limbische System und die Amygdala dysregulieren und so die Anfälligkeit für die Entwicklung von Angststörungen erhöhen (Garakani et al., 2006). Aktuelle globale Ereignisse, wie die COVID-19 Pandemie und andere Krisen können diese Prozesse durch chronischen Stress verschärfen, und so zu einer weiter steigenden Prävalenz von Angststörungen führen (Kazmi et al., 2020). Es ist von zentraler Bedeutung Wege zu Verbesserung von Therapieoptionen für Angststörungen, insbesondere zur weiteren Verbesserung der Expositionstherapie, zu finden. Neben dem Einsatz von zusätzlich zur Expositionstherapie verabreichten klassischen Psychopharmaka, erweist sich die Verwendung von so-genannten kognitiven Verstärkern, also Substanzen, welche neurokognitive Prozesse wie Aufmerksamkeit, Gedächtnis und Lernen beeinflussen, als vielversprechend. Studien haben mehrere solcher Substanzen identifiziert, welche bereits im Kontext der Angstextinktion positive Effekte zeigten, darunter Hormone wie Oxytocin oder Cortisol (Brueckner et al., 2019; de Quervain et al., 2009; Eckstein et al., 2015, 2019). Ziel der vorliegenden Arbeit ist es, die Rolle von Umweltstress und kognitiven Verstärkern als modulierende Faktoren von Angstkonditionierungsprozessen zu untersuchen. Dabei wurden mehrere Ziele verfolgt und insgesamt drei empirische Studien durchgeführt. Ziel der ersten Studie war es das Potential von intra-nasal verabreichtem Insulin als kognitiver Verstärker bei der Extinktion von Angst zu untersuchen. Zu diesem Zweck wurde eine klassische Angstkonditionierungsstudie mit gesunden ProbandInnen durchgeführt. Vor der Extinktion wurde den ProbandInnen entweder Insulin oder ein Placebo per Nasenspray verbreicht. ProbandInnen der Insulingruppe zeigten eine stärkere Abnahme der Angstreaktion während der Extinktion, was einen ersten Hinweis für die förderliche Wirkung von intranasalem Insulin als kognitiver Verstärker der Angstextinktion darstellt. In der zweiten Studie wurde untersucht, wie sich auf die COVID-19 Pandemie bezogene Ängste auf das Angstlernen und die Angstgeneralisierung aus-wirken. Ziel war es zu untersuchen, ob eine erhöhte Ängstlichkeit während CO-VID-19 zu einer verstärkten Konditionierbarkeit und Generalisierung von Angst führen kann. Dazu wurde eine klassische Angstkonditionierungsstudie mit gesunden ProbandInnen durchgeführt und die COVID-19 bezogene Ängstlichkeit gemessen. ProbandInnen mit höherer COVID-19 bezogener Ängstlichkeit zeigten eine Tendenz zur schlechteren Diskriminierung zwischen sicheren und gefährlichen Reizen während des Angstlernens sowie eine stärker ausgeprägte Generalisierung der Angstreaktion. Aufbauend auf den Ergebnissen der ersten Studie wurde in der dritten Studie untersucht, ob die Verabreichung von Glukose als kognitiver Verstärker die Effekte der Angstextinktion verbessern kann. Es wurden zwei Angstkonditionierungsstudien mit gesunden ProbandInnen durchgeführt, bei denen den ProbandInnen vor (Studie 1) bzw. nach der Extinktion (Studie 2) entweder Glukose oder ein Placebo verabreicht wurde. ProbandInnen der Glukosegruppe zeigten eine stärkere Abnahme der Angstreaktion während der Extinktion (Studie 1) und einem späteren Abruf (Studie 2), was einen ersten Beleg für die Wirksamkeit von Glukose als kognitiver Verstärker bei der Extinktion von Angst darstellt. Zusammenfassend liefern die drei in dieser Arbeit vorgestellten Studien wichtige Erkenntnisse für die aktuelle Forschung zu Prozessen der Angstextinktion und beispielsweise deren mögliche Verbesserung durch kognitive Verstärker wie Insulin oder Glukose. Zudem wird die Bedeutung von umweltbezogenen Stressfaktoren auf die Entstehung und Aufrechterhaltung von Angststörungen durch den nachgewiesenen Einfluss des COVID-19 bezogenen Angsterlebens auf wichtige Angstlernprozesse, wie die Generalisierung von Angst, unterstrichen. Durch die Integration der gewonnenen Erkenntnisse tragen die Studien zu einem besseren Verständnis von Angstlernprozessen bei und legen dabei den Grund-stein für weitere Forschung, um mit deren Hilfe praktische Implikationen für die Verbesserung der Expositionstherapie gewinnen zu können

Do Dogs Really Influence How People Evaluate Psychotherapists? A Conceptual Replication Attempt

The icebreaker effect – the idea that integrating animals into psychotherapy improves the therapeutic alliance – is believed to be one of the main mechanisms of action in animal-assisted psychotherapy. Support for this notion has come from preliminary evidence that the presence of a dog positively influences how people perceive psychotherapists. However, the robustness and generalizability of these findings have yet to be tested. Thus, in our study, we aimed to (1) conceptually replicate these results and (2) gain insight into what might drive them by employing a design with high experimental control. Four hundred and eighty-one participants took part in our experiment, in which they first watched a video of a psychotherapist introducing themself. In the video, we experimentally manipulated whether the psychotherapist had an additional qualification in animal-assisted therapy or in meditation techniques and mindfulness (as a control condition), whether the psychotherapist referred to this additional qualification in the video, whether this additional qualification was visible in the video (dog or meditation accessories visible), and the psychotherapist's gender. After watching the video, participants were asked to report on the anticipated therapeutic relationship, the perceived trustworthiness of the therapist, and their own willingness to self-disclose. None of our analyses yielded any evidence of positive effects from the presence of a dog in the video. Thus, we could not replicate the previous results. Given our design, we argue that our results suggest that it is neither the mere presence of the dog (i.e., the visibility of the dog in the video) nor the perception of the psychotherapist's ability to work with a dog as an additional qualification that drove the previously found positive effects. Instead, we discuss the idea that these positive effects might be due to (potentially unconscious) changes in psychotherapists’ behavior and performance when accompanied by a dog. We invite future research to investigate (1) the role that therapists’ behavioral changes due to the presence of a dog play and (2) under which circumstances these changes occur