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

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

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

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

A Systematic Review and Meta-Analysis on the Safety of Antiplatelet Discontinuation Following Stent-Assisted Coil Embolization for Cerebral Aneurysms

Background: Stent-assisted coil embolization (SACE) is a common endovascular technique for managing intracranial aneurysms. The permanent presence of a stent inside the cerebral artery necessitates the postoperative use of antiplatelets. However, a consensus about how long to continue on it remains debated. This systematic review aims to discuss and quantify the risk of ischemic complications after antiplatelet discontinuation following SACE. Methods: PubMed, Cochrane Library, Scopus, and Web of Science (WOS) were systematically searched for studies assessing the outcomes after antiplatelet discontinuation following SACE for cerebral aneurysms. The primary outcome was the odds of ischemic complications after antiplatelet discontinuation. Using a random-effects model, the pooled event rate, along with a 95% confidence interval (CI), was calculated. The Comprehensive Meta-Analysis software (CMA) software was used for the analysis. The Newcastle–Ottawa Scale (NOS) was used for the quality assessment. Results: A total of five observational cohort studies were included in this systematic review. The studies recruited cases from 2009 and 2020, predominantly in Korea and Japan. Data from 18,425 cases obtained from four studies were analyzed. The duration of antiplatelet therapy varied widely across the included studies. Additionally, most studies reported a median follow-up of 24 months or more after antiplatelet discontinuation. We extracted and analyzed the odds of thromboembolic complications occurring within 6 to 24 months after the discontinuation of antiplatelets. The pooled rate of thromboembolism after antiplatelet discontinuation in this meta-analysis was 0.01 (95% CI: 0.006 to 0.018). Conclusion: This review demonstrates that the risk of thromboembolic complications after discontinuing antiplatelet therapy post SACE is low. However, no strong consensus exists on the ideal duration for maintaining dual- or single-antiplatelet therapy. Further prospective studies with longer follow-ups are warranted to clarify the optimal durations needed to balance thromboembolic risk with hemorrhagic complications

Synthese von Bottromycin-Derivaten und Totalsynthese von Crossiguanipyrazin I

Der erste Teil dieser Arbeit befasst sich mit der Synthese neuer Bottromycin-Derivate. Dafür wurde eine flexible und konvergente Synthesestrategie entwickelt, die eine Modifizierung an nahezu jeder Stelle des Bottromycin-Gerüsts zulässt. Die dafür benötigten Peptid-Bausteine wurden mit Hilfe der Ugi Reaktion aufgebaut und waren damit in nur einem Schritt schnell verfügbar. Im Schlüsselschritt der Synthese wurden diese in einer Quecksilber-vermittelten Amidinierung miteinander geknüpft und abschließend makrolactamisiert. Außerdem gelang die enantioselektive Herstellung der in der Seitenkette befindlichen ungewöhnlichen Aminosäure (2S,3S)-3-Methylphenylalanin unter Verwendung der Matteson-Homologisierung. Insgesamt konnten sechs verschiedene Derivate hergestellt und biologisch evaluiert werden. Zwei der getesteten Derivate zeigten eine biologische Aktivität gegen verschiedene gram-positive Bakterien. Im zweiten Teil dieser Arbeit wird, zur Verifizierung der postulierten Struktur, die Totalsynthese des Naturstoffs Crossiguanipyrazin I behandelt. Bei der Synthese handelt es sich um die erste Totalsynthese dieser Naturstoffklasse. Die Crossiguanipyrazine wurden 2024 von Fu et al. aus dem Actinobacterium Crossiella cryophila DSM44230 isoliert und weisen eine potente Anti-tuberkulose Wirkung auf. Zentraler Bestandteil der Synthese war der Aufbau des vierfach substituierten Pyrazin-Rings sowie die simultane Einführung dreier Guanidin-Gruppen.In the first part of this PhD thesis the synthesis of new bottromycin derivatives is reported. A flexible and convergent synthetic strategy was developed, enabling modifications at nearly any position of the bottromycin scaffold. The required peptide building blocks were synthesized using the Ugi reaction, making them easily available in just one step. In the key step of the synthesis, these building blocks were coupled via a mercury-mediated amidination, followed by macrolactamization. Additionally, the enantioselective synthesis of the unusual amino acid (2S,3S)-3-methylphenylalanine was achieved using the Matteson homologation. A total of six different derivatives were synthesized and biologically evaluated. Two of these derivatives demonstrated biological activity against various gram-positive bacteria. The second part of this thesis describes the total synthesis of the natural product crossiguanipyrazine I to confirm the postulated structure. The synthesis represents the first total synthesis of this class of natural products. Crossiguanipyrazines were isolated from the actinobacterium Crossiella cryophila DSM44230 in 2024 by Fu et al. and show some potent anti-tuberculosis activity. The key steps of the synthesis involved the formation of the fourfold substituted pyrazine ring and the simultaneous introduction of three guanidine groups

Methodik zur Evaluierung von Auswirkungen der geometrischen Komplexität auf die Produktivität additiver Fertigungsverfahren am Beispiel des Selektiven Lasersinterns

Als einer der bedeutendsten Vorteile Additiver Fertigungsverfahren wird häufig die Gestaltungsfreiheit genannt. Jedoch bestehen Herausforderungen, da die suggerierte Gestaltungsfreiheit meist ohne Berücksichtigung der verschiedenen Verfahren und Wirkprinzipien dargestellt wird. Dabei zeigt sich im Vergleich unterschiedlicher Verfahren, dass die zu erzeugende Geometrie zum Teil signifikante Auswirkungen auf den Produktionsaufwand in Form von Zeit und Kosten hat. Mit der vorliegenden Arbeit werden diese Problemstellungen aufgegriffen und eine Methodik entwickelt, welche die Evaluierung von Auswirkungen der geometrischen Komplexität auf den additiven Herstellprozess ermöglicht. Demonstriert wird die Methodik am Verfahren des Selektiven Lasersinterns (SLS) für Kunststoffe. Der Fokus liegt dabei auf der Analyse von Zusammenhängen zwischen geometrischen Einflussfaktoren, Prozessparametern sowie resultierenden Produktionsaufwänden. Unter Beibehaltung von Randbedingungen wie dem Bauteilvolumen und der Bauhöhe wird gezeigt, dass sich die Generierdauer durch Steigerung der Komplexität zum Teil mehr als verdreifacht. Mithilfe der entwickelten Methodik können diese Auswirkungen direkt auf das Wechselspiel aus Geometrie und prozessspezifischen Faktoren, wie den Laserscanpfaden zurückgeführt werden. Folglich ist eine quantitative Kategorisierung der Komplexität in Abhängigkeit des Verfahrens möglich, die zusätzlich Rückschlüsse zur Gestaltung von Bauteilen und Bauaufträgen gewährt.Freedom of design is often cited as one of the major advantages of additive manufacturing. However, challenges remain, as the supposed freedom of design is usually presented without considering the various processes and operating principles. The comparison of different processes shows that the geometry to be produced sometimes has a significant impact on production effort in terms of time and costs. In this work, these challenges are addressed and a methodology is developed to assess the impact of geometric complexity on additive manufacturing processes. The methodology is demonstrated using the Selective Laser Sintering (SLS) for plastics. The focus is on the analysis of correlations between geometric influencing factors, process parameters and the resulting production effort. While maintaining boundary conditions such as part volume and build height, the results reveal that the generation time is more than tripled in some cases due to an increase in complexity. By using the developed methodology, these effects can be linked directly to the interaction of geometry and process-specific factors, such as the laser scan paths. Consequently, a quantitative categorization of the complexity in relation to the specific process is possible, which also allows conclusions to be made with regard to the design of parts and build jobs.2022-10 to 2025-05 | Grant Federal Ministry for Economic Affairs and Climate Action (BMWK) (Berlin, DE

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