Minimally invasive repair of pectus excavatum in a 17-year-old boy with a history of congenital diaphragmatic hernia and lack of pericardium

AbstractWe reported a 17-year-old boy with very deep asymmetric pectus excavatum and with a history of congenital diaphragmatic hernia repair and hypoplastic left lung. We performed a minimally invasive repair of pectus excavatum as described by Nuss et al., in 1998. We performed a left-sided thoracoscopy, instead of the right-sided according our normal routine, to provide a safe route. We created a substernal tunnel to have a clear definition of the deviant anatomy after congenital diaphragmatic hernia repair. However, we noticed an absence of the pericardium, which, by itself, can increase the risk of cardiac injury in both bar insertion and removal. Instead of the usual right-sided thoracoscopy, we recommend providing a safe view by left-sided thoracoscopy in comparable cases (e.g. congenital diaphragmatic hernia, other cardiac or vascular malformations) to reduce the risk of rupture or perforation of cardiac structures

Biodiversity and food web indicators of community recovery in intertidal shellfish reefs

Contains fulltext : 168969.pdf (publisher's version ) (Closed access)8 p

Positive Feedbacks in Seagrass Ecosystems – Evidence from Large-Scale Empirical Data

Positive feedbacks cause a nonlinear response of ecosystems to environmental change and may even cause bistability. Even though the importance of feedback mechanisms has been demonstrated for many types of ecosystems, their identification and quantification is still difficult. Here, we investigated whether positive feedbacks between seagrasses and light conditions are likely in seagrass ecosystems dominated by the temperate seagrass Zostera marina. We applied a combination of multiple linear regression and structural equation modeling (SEM) on a dataset containing 83 sites scattered across Western Europe. Results confirmed that a positive feedback between sediment conditions, light conditions and seagrass density is likely to exist in seagrass ecosystems. This feedback indicated that seagrasses are able to trap and stabilize suspended sediments, which in turn improves water clarity and seagrass growth conditions. Furthermore, our analyses demonstrated that effects of eutrophication on light conditions, as indicated by surface water total nitrogen, were on average at least as important as sediment conditions. This suggests that in general, eutrophication might be the most important factor controlling seagrasses in sheltered estuaries, while the seagrass-sediment-light feedback is a dominant mechanism in more exposed areas. Our study demonstrates the potentials of SEM to identify and quantify positive feedbacks mechanisms for ecosystems and other complex systems

Electromagnetic vertex function of the pion at T > 0

The matrix element of the electromagnetic current between pion states is calculated in quenched lattice QCD at a temperature of $T = 0.93 T_c$. The nonperturbatively improved Sheikholeslami-Wohlert action is used together with the corresponding ${\cal O}(a)$ improved vector current. The electromagnetic vertex function is extracted for pion masses down to $360 {\rm MeV}$ and momentum transfers $Q^2 \le 2.7 {\rm GeV}^2$.Comment: 17 pages, 8 figure

Positive Feedbacks in Seagrass Ecosystems – Evidence from Large-Scale Empirical Data

Positive feedbacks cause a nonlinear response of ecosystems to environmental change and may even cause bistability. Even though the importance of feedback mechanisms has been demonstrated for many types of ecosystems, their identification and quantification is still difficult. Here, we investigated whether positive feedbacks between seagrasses and light conditions are likely in seagrass ecosystems dominated by the temperate seagrass Zostera marina. We applied a combination of multiple linear regression and structural equation modeling (SEM) on a dataset containing 83 sites scattered across Western Europe. Results confirmed that a positive feedback between sediment conditions, light conditions and seagrass density is likely to exist in seagrass ecosystems. This feedback indicated that seagrasses are able to trap and stabilize suspended sediments, which in turn improves water clarity and seagrass growth conditions. Furthermore, our analyses demonstrated that effects of eutrophication on light conditions, as indicated by surface water total nitrogen, were on average at least as important as sediment conditions. This suggests that in general, eutrophication might be the most important factor controlling seagrasses in sheltered estuaries, while the seagrass-sediment-light feedback is a dominant mechanism in more exposed areas. Our study demonstrates the potentials of SEM to identify and quantify positive feedbacks mechanisms for ecosystems and other complex systems

Continuous deep sedation at the end of life:a qualitative interview-study among health care providers on an evolving practice

Background:Continuous deep sedation (CDS) can be used for patients at the end of life who suffer intolerably from severe symptoms that cannot be relieved otherwise. In the Netherlands, the use of CDS is guided by an national guideline since 2005. The percentage of patients for whom CDS is used increased from 8% of all patients who died in 2005 to 18% in 2015. The aim of this study is to explore potential causes of the rise in the use of CDS in the Netherlands according to health care providers who have been participating in this practice. Methods: Semi-structured interviews were conducted and thematically analysed. Participants were Dutch health care providers (HCPs), working at patients’ homes, hospices, elderly care facilities and in hospitals and experienced in providing CDS, who were recruited via purposeful sampling. Results: 41 Health care providers participated in an interview. For these HCPs the reason to start CDS is often a combination of symptoms resulting in a refractory state. HCPs indicated that symptoms of non-physical origin are increasingly important in the decision to start CDS. Most HCPs felt that suffering at the end of life is less tolerated by patients, their relatives, and sometimes by HCPs; they report more requests to relieve suffering by using CDS. Some HCPs in our study have experienced increasing pressure to perform CDS. Some HCPs stated that they more often used intermittent sedation, sometimes resulting in CDS. Conclusions: This study provides insight into how participating HCPs perceive that their practice of CDS changed over time. The combination of a broader interpretation of refractory suffering by HCPs and a decreased tolerance of suffering at the end of life by patients, their relatives and HCPs, may have led to a lower threshold to start CDS. Trial registration: The Research Ethics Committee of University Medical Center Utrecht assessed that the study was exempt from ethical review according to Dutch law (Protocol number 19–435/C).</p

Habitat modification by marram grass negatively affects recruitment of conspecifics

Ecosystem engineers alter their environment often benefiting their own survival and growth yielding self-reinforcing feedbacks. Moreover, these habitat modifications have been found to facilitate recruitment of conspecifics for some species, while for others engineering inhibits recruitment. Whether dune grasses facilitate or inhibit recruitment of conspecifics is yet unknown. Here, we investigated how habitat modification by European marram grass (Ammophila arenaria) through embryonic dune development affects recruitment from seeds and marine dispersed rhizome fragments. Specifically, we tested at three locations with different dune morphologies how habitat modification affected natural seed and rhizome presence and shoot emergence from plots in which seeds or rhizome fragments were added. In addition, we investigated how sediment burial (i.e., the main effect of habitat modification by dune grasses) affected germination and emergence in a controlled experiment. Results show that regardless of habitat modification or beach width, seeds and rhizomes were absent in natural conditions. Habitat modification negatively affected shoot emergence from seeds (8 × less) and rhizomes (4 × less) and was negatively related to sediment dynamics. Furthermore, fewer seedlings were found with higher elevations. In controlled laboratory conditions, the highest seedling emergence was found with slight burial (0.5-3 cm); both germination and seedling emergence decreased as seeds were buried deeper or shallower. Overall, habitat modification by marram grass negatively affects recruitment of conspecifics through increased sediment dynamics and elevation. Consequently, storm events or eradication programs that include removal of adult vegetation—which leads to an unmodified system—might benefit new recruitment from seeds or clonal fragments

GPU-accelerated Bloch simulations and MR-STAT reconstructions using the Julia programming language

PURPOSE: MR-STAT is a relatively new multiparametric quantitative MRI technique in which quantitative paramater maps are obtained by solving a large-scale nonlinear optimization problem. Managing reconstruction times is one of the main challenges of MR-STAT. In this work we leverage GPU hardware to reduce MR-STAT reconstruction times. A highly optimized, GPU-compatible Bloch simulation toolbox is developed as part of this work that can be utilized for other quantitative MRI techniques as well. METHODS: The Julia programming language was used to develop a flexible yet highly performant and GPU-compatible Bloch simulation toolbox called BlochSimulators.jl. The runtime performance of the toolbox is benchmarked against other Bloch simulation toolboxes. Furthermore, a (partially matrix-free) modification of a previously presented (matrix-free) MR-STAT reconstruction algorithm is proposed and implemented using the Julia language on GPU hardware. The proposed algorithm is combined with BlochSimulators.jl and the resulting MR-STAT reconstruction times on GPU hardware are compared to previously presented MR-STAT reconstruction times. RESULTS: The BlochSimulators.jl package demonstrates superior runtime performance on both CPU and GPU hardware when compared to other existing Bloch simulation toolboxes. The GPU-accelerated partially matrix-free MR-STAT reconstruction algorithm, which relies on BlochSimulators.jl, allows for reconstructions of 68 seconds per two-dimensional (2D slice). CONCLUSION: By combining the proposed Bloch simulation toolbox and the partially matrix-free reconstruction algorithm, 2D MR-STAT reconstructions can be performed in the order of one minute on a modern GPU card. The Bloch simulation toolbox can be utilized for other quantitative MRI techniques as well, for example for online dictionary generation for MR Fingerprinting