What makes a responsible leader? - An empirical analysis of how personality characteristics affect leadership behaviour

This master’s thesis contributes to the ongoing discussion on responsible leadership and its antecedents by empirically analysing the relationship between various traits and responsible leadership effectiveness. In a quantitative experimental research study, the participants (62 men and 32 women) first filled out an online survey assessing their gender, age, and major field of study as well as their score in the personality dimensions honesty-humility, openness to experience, empathic concern, perspective taking, and holism. Afterwards, their second-to-fourth digit ratio was measured, and men had the option of providing a saliva sample which was used to determine their testosterone level. Finally, the participants’ performance in the leadership roles professional, facilitator, citizen, idea-provider, and total was assessed with a think-aloud protocol. By performing a multiple linear regression analysis, I found that empathic concern positively influences the roles facilitator and total, holism the role citizen, and perspective taking the role idea-provider. I also found that men and psychology students are less likely to perform well in the role idea-provider and that openness to experience negatively affects facilitator. This master’s thesis contributes to the ongoing discussion on responsible leadership and its antecedents by empirically analysing the relationship between various traits and responsible leadership effectiveness. In a quantitative experimental research study, the participants (62 men and 32 women) first filled out an online survey assessing their gender, age, and major field of study as well as their score in the personality dimensions honesty-humility, openness to experience, empathic concern, perspective taking, and holism. Afterwards, their second-to-fourth digit ratio was measured, and men had the option of providing a saliva sample which was used to determine their testosterone level. Finally, the participants’ performance in the leadership roles professional, facilitator, citizen, idea-provider, and total was assessed with a think-aloud protocol. By performing a multiple linear regression analysis, I found that empathic concern positively influences the roles facilitator and total, holism the role citizen, and perspective taking the role idea-provider. I also found that men and psychology students are less likely to perform well in the role idea-provider and that openness to experience negatively affects facilitator.  Keywords: Responsible leadership, Ethical leadership, Corporate social responsibility, Stakeholder approach, Personalitycharacteristic

Short-term effects of positive end-expiratory pressure on breathing pattern: an interventional study in adult intensive care patients

INTRODUCTION: Positive end-expiratory pressure (PEEP) is used in mechanically ventilated patients to increase pulmonary volume and improve gas exchange. However, in clinical practice and with respect to adult, ventilator-dependent patients, little is known about the short-term effects of PEEP on breathing patterns. METHODS: In 30 tracheally intubated, spontaneously breathing patients, we sequentially applied PEEP to the trachea at 0, 5 and 10 cmH(2)O, and then again at 5 cmH(2)O for 30 s each, using the automatic tube compensation mode. RESULTS: Increases in PEEP were strongly associated with drops in minute ventilation (P < 0.0001) and respiratory rate (P < 0.0001). For respiratory rate, a 1 cmH(2)O change in PEEP in either direction resulted in a change in rate of 0.4 breaths/min. The effects were exclusively due to changes in expiratory time. Effects began to manifest during the first breath and became fully established in the second breath for each PEEP level. Identical responses were found when PEEP levels were applied for 10 or 60 s. Post hoc analysis revealed a similar but stronger response in patients with impaired respiratory system compliance. CONCLUSION: In tracheally intubated, spontaneously breathing adult patients, the level of PEEP significantly influences the resting short-term breathing pattern by selectively affecting expiratory time. These findings are best explained by the Hering–Breuer inflation/deflation reflex

Transcranial color-coded duplex sonography allows to assess cerebral perfusion pressure noninvasively following severe traumatic brain injury

Objective: Assess optimal equation to noninvasively estimate intracranial pressure (eICP) and cerebral perfusion pressure (eCPP) following severe traumatic brain injury (TBI) using transcranial color-coded duplex sonography (TCCDS). Design and setting: This is an observational clinical study in a university hospital. Patients: A total of 45 continuously sedated (BIS  35mmHg), and non-febrile TBI patients. Methods: eICP and eCPP based on TCCDS-derived flow velocities and arterial blood pressure values using three different equations were compared to actually measured ICP and CPP in severe TBI patients subjected to standard treatment. Optimal equation was assessed by Bland-Altman analysis. Results: The equations: $${\hbox{ICP}} = {1}0.{927} \times {\hbox{PI}}\left( {{\hbox{pulsatility}}\,{\hbox{index}}} \right) - {1}.{284}$$ and $${\hbox{CPP}} = {89}.{646} - {8}.{258} \times {\hbox{PI}}$$ resulted in eICP and eCPP similar to actually measured ICP and CPP with eICP 10.6 ± 4.8 vs. ICP 10.3 ± 2.8 and eCPP 81.1 ± 7.9 vs. CPP 80.9 ± 2.1mmHg, respectively. The other two equations, $${\hbox{eCPP}} = \left( {{\hbox{MABP}} \times {\hbox{EDV}}} \right)/{\hbox{mFV}} + {14}$$ and $${\hbox{eCPP}} = \left[ {{\hbox{mFV}}/\left( {{\hbox{mFV}} - {\hbox{EDV}}} \right)} \right] \times \left( {{\hbox{MABP}} - {\hbox{RRdiast}}} \right)$$, resulted in significantly decreased eCPP values: 72.9 ± 10.1 and 67 ± 19.5mmHg, respectively. Superiority of the first equation was confirmed by Bland-Altman revealing a smallest standard deviations for eCPP and eICP. Conclusions: TCCDS-based equation $$\left( {{\hbox{ICP}} = {1}0.{927} \times {\hbox{PI}} - {1}.{284}} \right)$$ allows to screen patients at risk of increased ICP and decreased CPP. However, adequate therapeutic interventions need to be based on continuously determined ICP and CPP value

Ex vivo microangioCT: Advances in microvascular imaging

Therapeutic modulation of angiogenesis is believed to be a prospective powerful treatment strategy to modulate the microcirculation and therefore help millions of patients with cardiovascular and cancer diseases. The often-frustrating results from late-stage clinical studies indicate an urgent need for improved assessment of the pro- and anti-angiogenic compounds in preclinical stage of investigation. For such a proper assessment, detailed vascular visualization and adequate quantification are essential. Nowadays, there are few imaging modalities available, but none of them provides non-destructive 3D-visualization of the vasculature down to the capillary level. In many instances, the approaches cannot be combined with the subsequent histological or ultrastructural analysis. In this review, we address the latest developments in the microvascular imaging, namely, the microangioCT approach with a polymer-based contrast agent (μAngiofil). This approach allows time-efficient non-destructive 3D-imaging of the organ and its vasculature including the finest capillaries. Besides the superior visualization, the obtained detailed 3D information on the organ vasculature enables its 3D-skeletonization and further quantitative analysis. Probably the only significant limitation of the described approach is that it can be used only ex vivo, i.e., no longitudinal studies. In spite of this drawback, microangioCT with μAngiofil is a relatively simple and straightforward tool with a broad application range for studying physiological and pathological alterations in the microvasculature of any organ. It provides microvascular imaging at unprecedented level and enables correlative microscopy

Micro-CT imaging of Thiel-embalmed and iodine-stained human temporal bone for 3D modeling

Introduction This pilot study explores whether a human Thiel-embalmed temporal bone is suitable for generating an accurate and complete data set with micro-computed tomography (micro-CT) and whether solid iodine-staining improves visualization and facilitates segmentation of middle ear structures. Methods A temporal bone was used to verify the accuracy of the imaging by first digitally measuring the stapes on the tomography images and then physically under the microscope after removal from the temporal bone. All measurements were compared with literature values. The contralateral temporal bone was used to evaluate segmentation and three-dimensional (3D) modeling after iodine staining and micro-CT scanning. Results The digital and physical stapes measurements differed by 0.01–0.17 mm or 1–19%, respectively, but correlated well with the literature values. Soft tissue structures were visible in the unstained scan. However, iodine staining increased the contrast-to-noise ratio by a factor of 3.7 on average. The 3D model depicts all ossicles and soft tissue structures in detail, including the chorda tympani, which was not visible in the unstained scan. Conclusions Micro-CT imaging of a Thiel-embalmed temporal bone accurately represented the entire anatomy. Iodine staining considerably increased the contrast of soft tissues, simplified segmentation and enabled detailed 3D modeling of the middle ear

Fossil Carychiidae (Eupulmonata, Ellobioidea) from the Lower Pleistocene Nashua Formation of Florida, with the description of a new species.

Recent fossil shell mining for a new rail line in the Orlando area of Orange County, Florida has uncovered two species of the ellobioid genus Carychium O. F. Müller, 1773 in a bed of freshwater marl from the Lower Pleistocene Nashua Formation. To taxonomically interpret these finds, the well-preserved shells were imaged via high-resolution X-ray tomography (micro-CT) to view significant internal diagnostic characters such as the columellar configuration and the degree of lamellar sinuosity and their relationship in context to the entire shell. The image data are compared to that of type material and extant and fossil Carychium species inhabiting the SE USA, Mexico, Central America, and Jamaica. Based on these results, the species Carychiumfloridanum G. H. Clapp, 1918 and Carychiumnashuaensesp. nov. are identified from fossil shells dating from the Early Pleistocene. This work documents the first fossil members of C.floridanum and the first fossil Carychium from the SE USA

Synchrotron microtomography reveals the fine three-dimensional porosity of composite polysaccharide aerogels

This study investigates the impact of ice-templating conditions on the morphological features of composite polysaccharide aerogels in relation to their mechanical behavior and aims to get a better insight into the parameters governing these properties. We have prepared polysaccharide aerogels of guar galactomannan (GM) and tamarind seed xyloglucan (XG) by enzymatic oxidation with galactose oxidase (GaO) to form hydrogels, followed by conventional and unidirectional ice-templating (freezing) methods and lyophilization to form aerogels. Composite polysaccharide aerogels were prepared by incorporating nanofibrillated cellulose (NFC) into polysaccharide solutions prior to enzymatic oxidation and gel formation; such a cross linking technique enabled the homogeneous distribution of the NFC reinforcement into the gel matrix. We conducted phase-enhanced synchrotron X-ray microtomography (XMT) scans and visualized the internal microstructure of the aerogels in three-dimensional (3D) space. Volume-weighted pore-size and pore-wall thickness distributions were quantitatively measured and correlated to the aerogels’ mechanical properties regarding ice-templating conditions. Pore-size distribution and orientation depended on the ice-templating methods and the NFC reinforcement that significantly determined the mechanical and shape-recovery behavior of the aerogels. The results obtained will guide the design of the microporous structure of polysaccharide aerogels with optimal morphology and mechanical behavior for life-sciences applications.Peer reviewe

Correlative Imaging of the Murine Hind Limb Vasculature and Muscle Tissue by MicroCT and Light Microscopy

A detailed vascular visualization and adequate quantification is essential for the proper assessment of novel angiomodulating strategies. Here, we introduce an ex vivo micro-computed tomography (microCT)-based imaging approach for the 3D visualization of the entire vasculature down to the capillary level and rapid estimation of the vascular volume and vessel size distribution. After perfusion with μAngiofil®, a novel polymerizing contrast agent, low- and high-resolution scans (voxel side length: 2.58-0.66 μm) of the entire vasculature were acquired. Based on the microCT data, sites of interest were defined and samples further processed for correlative morphology. The solidified, autofluorescent μAngiofil® remained in the vasculature and allowed co-registering of the histological sections with the corresponding microCT-stack. The perfusion efficiency of μAngiofil® was validated based on lectin-stained histological sections: 98 ± 0.5% of the blood vessels were μAngiofil®-positive, whereas 93 ± 2.6% were lectin-positive. By applying this approach we analyzed the angiogenesis induced by the cell-based delivery of a controlled VEGF dose. Vascular density increased by 426% mainly through the augmentation of medium-sized vessels (20-40 μm). The introduced correlative and quantitative imaging approach is highly reproducible and allows a detailed 3D characterization of the vasculature and muscle tissue. Combined with histology, a broad range of complementary structural information can be obtained