Semi-groups, groups and Lyapunov stability of partial differential equations

Applications of group theory and Liapunov stability to partial differential equation

Foot-operated cell-counter

Cell-counter for cell indices consists of a footboard with four pressure sensitive switches and an enclosure for the components and circuitry. This device increases the operators efficiency by reducing the number of required hand movements

Fibre laser hydrophones for cosmic ray particle detection

The detection of ultra high energetic cosmic neutrinos provides a unique means to search for extragalactic sources that accelerate particles to extreme energies. It allows to study the neutrino component of the GZK cut-off in the cosmic ray energy spectrum and the search for neutrinos beyond this limit. Due to low expected flux and small interaction cross-section of neutrinos with matter large experimental set-ups are needed to conduct this type of research. Acoustic detection of cosmic rays may provide a means for the detection of ultra-high energetic neutrinos. Using relative low absorption of sound in water, large experimental set-ups in the deep sea are possible that are able to detect these most rare events, but it requires highly sensitive hydrophones as the thermo-acoustic pulse originating from a particle shower in water has a typical amplitude as low as a mPa. It has been shown in characterisation measurements that the fibre optic hydrophone technology as designed and realised at TNO provides the required sensitivity. Noise measurements and pulse reconstruction have been conducted that show that the hydrophone is suited as a particle detector.Comment: Submitted to the proceedings of "13th Topical Seminar on Innovative Particle and Radiation Detectors (IPRD13)

Ut pictura poesis : Edward Black Greenshields' Collection of Hague School paintings

According to Edward Black Greenshields (1850-1917), the Hague School of artists were "all men of striking originality, [who] broke away from past traditions of art in their country, and, going directly to nature, strove, by careful study, to give a truthful view, each as he saw it..." 1 Financed by the industrial development of the late nineteenth and early twentieth century, he and the rest of Montreal's "merchant princes," formed a new class of art collectors rapidly purchasing European paintings. Greenshields, a noted industrialist and amateur scholar orchestrated the largest and most concentrated private amassing of "modern" Dutch works. Although he was one of the most important collectors of his time, little has been written about his activity in the Montreal art milieu. This paper investigates the nature of Greenshields' engagement with the Hague School and how as a collector and promoter of the group's work, he influenced the group's reception in Canada. At the height of his collecting Greenshields published two texts, A Subjective View of Landscape Painting (1904) and Landscape Painting and Modern Dutch Artists (1906). Combining art history and art criticism these works are now considered among the first of their kind produced in Canada. In this thesis I argue that Greenshields' collection and theoretical views on art as expressed in his writing evolved simultaneously and as his taste for works by the Hague School was formed his collection assumed a rhetorical function. By examining the mechanics of Greenshields' collection I provide a critical inquiry into connoisseurship during the formative stages of collecting in Canada. 1 E.B. Greenshields, The Subjective View of Landscape Painting: With Special Reference to J.H. Weissenbruch and Illustrations from His Works in Canada. (Montreal: Desbarats, 1903) 9

Expected issuance fees and market liquidity

We examine the interaction between the primary and secondary markets for euro area sovereign bonds. Primary dealers compete to be selected as lead manager in the primary market, and have an incentive to increase liquidity. For our 2008–2012 sample of sovereign bonds from 11 euro area countries, we find that expected issuance fees are positively and economically related to market liquidity. The fee-driven liquidity effect is especially strong for countries with high funding needs, in periods of high re-financing uncertainty, and for low-risk bonds

Low health literacy is associated with worse postoperative outcomes following hepato-pancreato-biliary cancer surgery

Background: Low health literacy (HL) can lead to worse health outcomes for patients with chronic diseases and could also lead to worse postoperative outcomes. This retrospective cohort study investigates the association between HL and postoperative textbook outcome (TO) after hepato-pancreato-biliary (HPB) cancer surgery. Methods: Patients that consented and underwent surgery for a premalignant andmalignant HPB tumor were included. Preoperatively, HL was measured by the brief health literacy screen (BHLS). Patients were categorized as having low or adequate HL. Primary outcome was TO (length of hospital stay (LOS) ≤ 75th percentile; and no severe complication; and no readmission and mortality within 30 days after discharge). Secondary outcomes were LOS and emergency department (ED) visits within 30 days after discharge. Results: In total, 137 patients were included, of whom thirty-six patients had low HL. In patients with low HL (vs. adequate HL), rate of TO was lower (55.6% vs. 72.3%; p = 0.095), LOS was significantly longer (13.5 vs. 9 days; p = 0.007) and there was only a slight difference in ED visits (14.3% vs. 11.0%; p = 0.560). Patients with low HL had a significant lower chance of achieving TO (OR 0.400, 95%-CI 0.169–0.948; p = 0.037). Conclusion: Low HL leads to worse postoperative outcome after HPB cancer surgery. Better preoperative education and guidance of patients with low HL could lead to better postoperative outcomes. Therefore, HL could be the next modifiable risk factor before major surgery

Development of an ex vivo model to study the response of skeletal muscle to transverse mechanical loading

Development of an ex vivo model to study the response of skeletal muscle to transverse mechanical loading. M. Graser, A. Wark, S. Day, A. Buis, The soft tissues in our body, particularly skeletal muscles, commonly experience physical stress. In most cases, the muscles can maintain the balance between damage and regeneration. However, this balance might be disturbed in certain populations that are subject to extreme cases  of overload or repeated impact, like individuals spinal cord injury [3] or transtibial prosthetic users [2].To characterise critical loading scenarios, experimental models of skeletal muscle under mechanical loading are necessary [4, 5]. A controllable environment as well as the reproduction of the highly hierarchical structure of skeletal muscle are thereby desirable. We therefore developed an ex vivo model to study the response of skeletal muscle to transverse mechanical loading. MethodsSoleus and extensor digitorum longus muscles of male Sprague Dawley rats were dissected and transversely compressed (2mm indenter, 9-32kPa) (Fig. 1). Control tissues were held under the same conditions for the same time without loading. Subsequently, tissue viability and morphology were assessed through standard histological procedures using Procion Yellow MX4R and Live-or-Dye™ for fluorescent dead cell staining as well as H&E. Additionally, biochemical changes of cell and tissue damaged were visualised with multiphoton Raman microscopy of unstained samples.Figure 1: Schematic of ex vivo model. A: Skeletal muscle dissection; B: Mechanical loading; C: Image analysis for cell damage; D: Data analysis to establish the relationship between loading conditions and cell damage.Results & DiscussionWhilst control samples showed only minor loss in cell viability throughout the experimental time frame (max. 3h), mechanical damage in loaded tissues was readily distinguishable. Imaging revealed a partial loss of cross-striations, disorganised and disrupted muscle fibres, increased interstitial space, and loss of cell viability. With careful control of the experimental setup, detailed imaging of local cellular damage in response to loading conditions could be obtained. ConclusionOur ex vivo model of skeletal muscle for transverse mechanical loading is suitable for quantifying cellular damage. Looking at this microscale will provide important insights into the adaptive capabilities of skeletal muscle. This can provide the basis for further research into the role of soft tissue deformation in limb pain and ulcer formation and could inform future directions for socket design and fit

Successful Thrombectomy via a Surgically Reopened Umbilical Vein for Extended Portal Vein Thrombosis Caused by Portal Vein Embolization prior to Extended Liver Resection

Selective portal vein embolization (PVE) before extended liver surgery is an accepted method to stimulate growth of the future liver remnant. Portal vein thrombosis (PVT) of the main stem and the non-targeted branches to the future liver remnant is a rare but major complication of PVE, requiring immediate revascularization. Without revascularization, curative liver surgery is not possible, resulting in a potentially life-threatening situation. We here present a new surgical technique to revascularize the portal vein after PVT by combining a surgical thrombectomy with catheter-based thrombolysis via the surgically reopened umbilical vein. This technique was successfully applied in a patient who developed thrombosis of the portal vein main stem, as well as the left portal vein and its branches to the left lateral segments after selective right-sided PVE in preparation for an extended right hemihepatectomy. The advantage of this technique is the avoidance of an exploration of hepatoduodenal ligament and a venotomy of the portal vein. The minimal surgical trauma facilitates additional intravascular thrombolytic therapy as well as the future right extended hemihepatectomy. We recommend this technique in patients with extensive PVT in which percutaneous less invasive therapies have been proven unsuccessful

Is surgical subspecialization associated with hand grip strength and manual dexterity?:A cross-sectional study

BACKGROUND: The aim of this study was to compare hand grip strength (HGS) and manual dexterity of academic, subspecialized surgeons. METHODS: A single-center cross-sectional study was performed among 61 surgeons. HGS was analysed with a hand dynamometer and manual dexterity was extensively analysed with a Purdue Pegboard Test. Correlations between HGS and manual dexterity and specific characteristics of the surgeons were analysed using Pearson's correlation coefficient (r). RESULTS: HGS and manual dexterity were comparable between surgeons from different specialities. HGS was positively correlated with male gender (r = 0.59, p < 0.001) and hand glove size (r = 0.61, p < 0.001), whereas manual dexterity was negatively correlated with male gender (r = −0.35, p = 0.006), age (r = −0.39, = 0.002), and hand glove size (r = −0.46, p < 0.001). CONCLUSIONS: Surgical subspecialization was not correlated with HGS or manual dexterity. Male surgeons have greater HGS, whereas female surgeons have better manual dexterity. Manual dexterity is also correlated with age, showing better scores for younger surgeons

The costs of complications and unplanned readmissions after pancreatoduodenectomy for pancreatic and periampullary tumors:Results from a single academic center

SIMPLE SUMMARY: Complications lead to unplanned readmissions (UR) and are reported to be associated with a two- to threefold increase in hospital admission costs. Since healthcare costs are increasing worldwide, cost containment is the major challenge for future healthcare. In the literature, there are only a few studies that analysed hospital costs after pancreatoduodenectomy (PD). In this study, we aimed to create an understanding of the costs of complications and UR in patients who underwent a PD. ABSTRACT: Background/Objectives: Complications after pancreatoduodenectomy (PD) lead to unplanned readmissions (UR), with a two- to threefold increase in admission costs. In this study, we aimed to create an understanding of the costs of complications and UR in this patient group. Furthermore, we aimed to generate a detailed cost overview that can be used to build a theoretical model to calculate the cost efficacy for prehabilitation. Methods: A retrospective cohort analysis was performed using the Dutch Pancreatic Cancer Audit (DPCA) database of patients who underwent a PD at our institute between 2013 and 2017. The total costs of the index hospital admission and UR related to the PD were collected. Results: Of the 160 patients; 35 patients (22%) had an uncomplicated course; 87 patients (54%) had minor complications, and 38 patients (24%) had severe complications. Median costs for an uncomplicated course were EUR 25.682, and for a complicated course, EUR 32.958 (p = 0.001). The median costs for minor complications were EUR 30.316, and for major complications, EUR 42.664 (p = 0.001). Costs were related to the Comprehensive Complication Index (CCI). The median costs of patients with one or more UR were EUR 41.199. Conclusions: Complications after PD led to a EUR 4.634–EUR 16.982 (18–66%) increase in hospital costs. A UR led to a cost increase of EUR 12.567 (44%). Since hospital costs are directly related to the CCI, reduction in complications will lead to cost-effectiveness