Orthotropic rotation-free thin shell elements

A method to simulate orthotropic behaviour in thin shell finite elements is proposed. The approach is based on the transformation of shape function derivatives, resulting in a new orthogonal basis aligned to a specified preferred direction for all elements. This transformation is carried out solely in the undeformed state leaving minimal additional impact on the computational effort expended to simulate orthotropic materials compared to isotropic, resulting in a straightforward and highly efficient implementation. This method is implemented for rotation-free triangular shells using the finite element framework built on the Kirchhoff--Love theory employing subdivision surfaces. The accuracy of this approach is demonstrated using the deformation of a pinched hemispherical shell (with a 18{\deg} hole) standard benchmark. To showcase the efficiency of this implementation, the wrinkling of orthotropic sheets under shear displacement is analyzed. It is found that orthotropic subdivision shells are able to capture the wrinkling behavior of sheets accurately for coarse meshes without the use of an additional wrinkling model.Comment: 10 pages, 8 figure

Transdermal β-Blocker Therapy in Essential Hypertension

Transdermal drug delivery has been applied to various agents in an effort to decrease the frequency of drug administration and increase the patients compliance. In our study, we demonstrated that transdermal application of a ß-blocker (20 mg mepindolol) in patients with essential hypertension led to effective blood pressure lowering effect within 1 week (160.1 ±6.1 mm Hg/95.8 ± 8.3 mm Hg vs 136.8 ± 7.2 mm Hg/84.3 ± 5.0 mm Hg; Ρ < 0.05). A controlled study of transdermal versus oral ß-blocker administration in hypertensives is necessary before this new therapeutic system is introduced in antihypertensive treatment. Am J Hypertens 1988; 1:199S-200

Collapse of orthotropic spherical shells

We report on the buckling and subsequent collapse of orthotropic elastic spherical shells under volume and pressure control. Going far beyond what is known for isotropic shells, a rich morphological phase space with three distinct regimes emerges upon variation of shell slenderness and degree of orthotropy. Our extensive numerical simulations are in agreement with experiments using fabricated polymer shells. The shell buckling pathways and corresponding strain energy evolution are shown to depend strongly on material orthotropy. We find surprisingly robust orthotropic structures with strong similarities to stomatocytes and tricolpate pollen grains, suggesting that the shape of several of Nature's collapsed shells could be understood from the viewpoint of material orthotropy.Comment: 7 pages, 5 figure

Subdivision Shell Elements with Anisotropic Growth

A thin shell finite element approach based on Loop's subdivision surfaces is proposed, capable of dealing with large deformations and anisotropic growth. To this end, the Kirchhoff-Love theory of thin shells is derived and extended to allow for arbitrary in-plane growth. The simplicity and computational efficiency of the subdivision thin shell elements is outstanding, which is demonstrated on a few standard loading benchmarks. With this powerful tool at hand, we demonstrate the broad range of possible applications by numerical solution of several growth scenarios, ranging from the uniform growth of a sphere, to boundary instabilities induced by large anisotropic growth. Finally, it is shown that the problem of a slowly and uniformly growing sheet confined in a fixed hollow sphere is equivalent to the inverse process where a sheet of fixed size is slowly crumpled in a shrinking hollow sphere in the frictionless, quasi-static, elastic limit.Comment: 20 pages, 12 figures, 1 tabl

Sammelrezension "Holocaust" und kein Ende

Ahren, Yizhak/Melchers, Christoph/Seifert, Werner/Wagner, Werner: Das Lehrstück 'Holocaust'Knilli, Friedrich/Zielinski, Siegfried (Hg.): Holocaust zur UnterhaltungKnilli, Friedrich/Zielinski, Siegfried (Hg.): Betrifft 'Holocaust'. Zuschauer schreiben an den WDRLichtenstein, Heiner/Schmid-Ospach, Michael (Hg.): Holocaust. Briefe an den WDRSiedler, Joachim: 'Holocaust'. Die Fernsehserie in der deutschen Press

Photon-Upconverting Materials: Advances and Prospects for Various Emerging Applications

Rare-earth-doped upconversion materials, featuring exceptional photophysical properties including long lifetime, sharp emission lines, large anti-Stokes shift, low autofluorescence of the background, and low toxicity, are promising for many applications. These materials have been investigated extensively since the 1960s and employed in many optical devices. However, due to rapid development of synthesis strategies for nanomaterials, upconversion materials have been rehighlighted on the basis of nanotechnology. Herein, we discuss the recent advances in upconversion materials. We start by considering energy transfer processes involved in the basic study of upconversion emission phenomena, as well as synthesis strategies of these materials. Progress in different energy transfer processes, which play an important role in determining luminescence efficiency, is then discussed. Newer applications of these materials have been vastly reviewed

The Time-related role of early pH, Base excess and Lactate for the Development in Sepsis in Polytrauma patients. An analysis using the IBM Watson Trauma Pathway Explorer

Triaging is essential for treating polytrauma patients. The Watson Trauma Pathway Explorer® represents an outcome prediction tool that prognosticates adverse events being Systemic Inflammatory Respiratory Syndrome and sepsis within 21 days and death within 72 h. We intended to compare the time- dependent role of pH, base excess (BE) and lactate for sepsis development in these patients. Retrospective data from 3653 patients were used. According to sepsis development, two groups were formed. pH, BE and lactate values were measured until up to 48 h after admission to our trauma bay. Differences in these three factors were analyzed between the two groups. Each factor (pH 2 or 4 mmol/L) was tested regarding its predictive quality, adjusted for ISS, age and gender. Threshold values at each timepoint were calculated. Between the two groups, differences in pH existed within the first 4 h, and for BE within the first six hours. Lactate values differed from the second hour onwards. pH ( 4 mmol/L; p = 0.006) at 4 h as well as BE at 6 h (< - 2 mmol/L; p = 0.022) were independent predictors for sepsis. Threshold values for pH were acidic for the first two hours, compared to BE within the first six hours. The insights indicating a time window of avoiding sepsis may allow referencing and promote timely measures while minimizing complications. Analysis of further surrogative parameters is required to warrant a more precise prediction

Sepsis in Polytrauma Patients: A Comparative Analysis of Damage Control versus Early Total Care regarding the Injury Severity Score using IBM Watson Pathway Explorer®

Sepsis presents a challenge in polytrauma patients care, where timing of procedures is crucial. The University Hospital of Zurich and IBM developed IBM Watson Trauma Pathway Explorer for predicting polytrauma complications such as SIRS, Sepsis, and early death within 72 hours. We intended to investigate the association of surgical treatment (Damage Control, DCS and Early Total Care, ETC) and injury severity (Injury Severity Score, ISS) with the development of sepsis. Data from 3653 patients was included. Patients were divided into two groups based on the type of surgical management (DCS, ETC) and injury severity (ISS ≤ 30, ISS > 30). The groups were assessed for the development of sepsis. Totally, 1242 patients had an ISS > 30 (34.6%), while 2374 had an ISS ≤ 30 (65.4%). DCS was conducted in 66.3% of cases versus 33.7% for ETC. DCS was performed in 73.5% of patients with an ISS > 30 and in 62.5% of patients with an ISS ≤ 30. ETC was performed in 26.5% for ISS > 30 and 37.5% for ISS ≤ 30. Sepsis was detected in 15% of the patients. 50.8% of sepsis cases had an initial ISS > 30. Regarding ETC, sepsis occurred in 9.6% of cases with ISS ≤ 30 and in 18.5% of cases with an ISS > 30. Regarding DCS, sepsis was detected in 12.3% with ISS ≤ 30 and in 23.4% with ISS > 30. Development of sepsis was associated with ISS > 30 (OR 2.21, p < 0.001) and DCS treatment (OR 1.45, p< 0.001). The findings confirm the association of sepsis development in polytrauma patients with a higher injury severity (ISS < 30). On the other hand, DCS does not generally imply a lower risk for this complication

The Road to Sepsis in Geriatric Polytrauma Patients-Can We Forecast Sepsis in Trauma Patients?

Background: Sepsis is a leading cause of mortality in polytrauma patients, especially beyond the first week, and its management is vital for reducing multiorgan failure and improving survival rates. This is particularly critical in geriatric polytrauma patients due to factors such as age-related physiological alterations and weakened immune systems. This study aimed to investigate various clinical and laboratory parameters associated with sepsis in polytrauma patients aged < 65 years and ≥65 years, with the secondary objective of comparing sources of infection in these patient groups. Methods: A retrospective cohort study was conducted at the University Hospital Zurich from August 1996 to December 2012. Participants included trauma patients aged ≥16 years with an Injury Severity Score (ISS) ≥ 16 who were diagnosed with sepsis within 31 days of admission. Patients in the age groups < 65 and ≥65 years were compared in terms of sepsis development. The parameters examined included patient and clinical data as well as laboratory values. The statistical methods encompassed group comparisons with Welch's t-test and logistic regression. Results: A total of 3059 polytrauma patients were included in the final study. The median age in the group < 65 years was 37 years, with a median ISS of 28. In the patient group ≥ 65 years, the median age was 75 years, with a median ISS of 27. Blunt trauma mechanism, ISS, leucocytosis at admission, and anaemia at admission were associated with sepsis in younger patients but not in geriatric patients, whereas sex, pH at admission, lactate at admission, and Quick values at admission were not significantly linked with sepsis in either age group. Pneumonia was the most common cause of sepsis in both age groups. Conclusions: Various parameters linked to sepsis in younger polytrauma patients do not necessarily correlate with sepsis in geriatric individuals with polytrauma. Hence, it becomes critical to recognize imminent danger, particularly in geriatric patients. In this context, the principle of "HIT HARD and HIT EARLY" is highly important as a proactive approach to effectively address sepsis in the geriatric trauma population, including the preclinical setting