164 research outputs found
Stepwise investment plan optimization for large scale and multi-zonal transmission system expansion
This paper develops a long term transmission expansion optimization methodology taking the probabilistic nature of generation and demand, spatial aspects of transmission investments and different technologies into account. The developed methodology delivers a stepwise investment plan to achieve the optimal grid expansion for additional transmission capacity between different zones. In this paper, the optimization methodology is applied to the Spanish and French transmission systems for long term optimization of investments in interconnection capacity
Long term investment optimization methodology for multi-zonal transmission expansion
This paper introduces a stepwise investment optimization methodology for transmission system expansion planning. The objective of the developed methodology is to determine transmission expansion plans to realize a desired interconnection capacity between multiple zones minimizing investment and operational costs. The methodology uses MILP optimization and a modified A∗ shortest path algorithm sequentially in order to determine the optimal investment time point, transmission topology, technology and routing. Spatial constraints and their effects on the installation cost are taken into account in the technology and route optimization. A possible application of the methodology is demonstrated on a stepwise investment plan for the North Sea region
Descending aortic calcification increases renal dysfunction and in-hospital mortality in cardiac surgery patients with intraaortic balloon pump counterpulsation placed perioperatively : a case control study
Introduction: Acute kidney injury (AKI) after cardiac surgery increases length of hospital stay and in-hospital mortality. A significant number of patients undergoing cardiac surgical procedures require perioperative intra-aortic balloon pump (IABP) support. Use of an IABP has been linked to an increased incidence of perioperative renal dysfunction and death. This might be due to dislodgement of atherosclerotic material in the descending thoracic aorta (DTA). Therefore, we retrospectively studied the correlation between DTA atheroma, AKI and in-hospital mortality.
Methods: A total of 454 patients were retrospectively matched to one of four groups: -IABP/-DTA atheroma, +IABP/-DTA atheroma, -IABP/+DTA atheroma, +IABP/+DTA atheroma. Patients were then matched according to presence/absence of DTA atheroma, presence/absence of IABP, performed surgical procedure, age, gender and left ventricular ejection fraction (LVEF). DTA atheroma was assessed through standard transesophageal echocardiography (TEE) imaging studies of the descending thoracic aorta.
Results: Basic patient characteristics, except for age and gender, did not differ between groups. Perioperative AKI in patients with -DTA atheroma/+IABP was 5.1% versus 1.7% in patients with -DTA atheroma/-IABP. In patients with +DTA atheroma/+IABP the incidence of AKI was 12.6% versus 5.1% in patients with +DTA atheroma/-IABP. In-hospital mortality in patients with +DTA atheroma/-IABP was 3.4% versus 8.4% with +DTA atheroma/+IABP. In patients with +DTA atheroma/+IABP in hospital mortality was 20.2% versus 6.4% with +DTA atheroma/-IABP. Multivariate logistic regression identified DTA atheroma > 1 mm (P = *0.002, odds ratio (OR) = 4.13, confidence interval (CI) = 1.66 to 10.30), as well as IABP support (P = *0.015, OR = 3.04, CI = 1.24 to 7.45) as independent predictors of perioperative AKI and increased in-hospital mortality. DTA atheroma in conjunction with IABP significantly increased the risk of developing acute kidney injury (P = 0.0016) and in-hospital mortality (P = 0.0001) when compared to control subjects without IABP and without DTA atheroma.
Conclusions: Perioperative IABP and DTA atheroma are independent predictors of perioperative AKI and in-hospital mortality. Whether adding an IABP in patients with severe DTA calcification increases their risk of developing AKI and mortality postoperatively cannot be clearly answered in this study. Nevertheless, when IABP and DTA are combined, patients are more likely to develop AKI and to die postoperatively in comparison to patients without IABP and DTA atheroma
Effect of preoperative statins in patients without coronary artery disease who undergo cardiac surgery
Objective3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) have been shown to have pleiotropic effects in addition to their lipid-lowering properties. Some studies have shown the beneficial effect of preoperative statins on operative outcomes in coronary artery bypass grafting. However, the effect of preoperative statins in patients without coronary artery disease who undergo cardiac surgery remains poorly defined.MethodsWe performed a retrospective review of 1389 consecutive patients undergoing cardiac valve surgery between January of 2002 and December of 2005. Patients undergoing concomitant coronary artery bypass surgery and those with a history of myocardial infarction and coronary interventions were excluded. Of this cohort, 363 patients were receiving a statin preoperatively and 1026 patients were not. Propensity scores were constructed with patients' demographics, clinical data, and the year of procedure. Generalized estimating equations, including the propensity score as a covariate, were used to investigate whether preoperative statin use is associated with improved operative outcomes.ResultsThe crude operative mortality rate was 0.8% and 2.3%, the incidence of stroke was 1.7% and 2.9%, and the incidence of perioperative myocardial infarction was 2.2% and 2.4% in the statin and non-statin groups, respectively. Generalized estimating equations showed that preoperative statin use is associated with lower mortality (odds ratio: 0.25, 95% confidential interval: 0.12–0.54). Preoperative statin use was not significantly associated with an incidence of stroke (odds ratio: 0.48, 95% confidential interval: 0.19–1.22) or perioperative myocardial infarction (odds ratio: 0.91, 95% confidential interval: 0.43–1.91) in this cohort.ConclusionPreoperative use of statins may improve operative outcomes in patients without coronary artery disease who undergo cardiac surgery
Targeted Expression of Cre Recombinase Provokes Placental-Specific DNA Recombination in Transgenic Mice
Background: Inadequate placental development is associated with a high incidence of early embryonic lethality and serious pregnancy disorders in both humans and mice. However, the lack of well-defined trophoblast-specific gene regulatory elements has hampered investigations regarding the role of specific genes in placental development and fetal growth. Principal Findings: By random assembly of placental enhancers from two previously characterized genes, trophoblast specific protein a (Tpbpa) and adenosine deaminase (Ada), we identified a chimeric Tpbpa/Ada enhancer that when combined with the basal Ada promoter provided the highest luciferase activity in cultured human trophoblast cells, in comparison with non-trophoblast cell lines. We used this chimeric enhancer arrangement to drive the expression of a Cre recombinase transgene in the placentas of transgenic mice. Cre transgene expression occurred throughout the placenta but not in maternal organs examined or in the fetus. Significance: In conclusion, we have provided both in vitro and in vivo evidence for a novel genetic system to achieve placental transgene expression by the use of a chimeric Tpbpa/Ada enhancer driven transgene. The availability of thi
An Application of the Concept of the Therapeutic Alliance To Sadomasochistic Pathology
This paper traces the history of the therapeutic alliance concept, examining how it has been used and misused, at times elevated to a central position and at others rejected altogether. The loss of this concept created a vacuum in classical psychoanalysis that has been filled by rival theories. The continuing usefulness of looking at the treatment process through the lens of the therapeutic alliance, particularly in relation to the manifold difficulties of working with sadomasochistic pathology, is suggested. To this end, revisions of the theory of the therapeutic alliance are suggested to address some of the difficulties that have arisen in conceptualizing this aspect of the therapeutic relationship, and to provide an integrated dynamic model for working with patients at each phase of treatment. This revised model acknowledges the complexity of the domain and encompasses the multiple tasks, functions, partners, and treatment phases involved. The utility of the revised theory is illustrated in application to understanding the sadomasochistic, omnipotent resistances of a female patient through the phases of her analysis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66889/2/10.1177_00030651980460031301.pd
Dissecting the First Transcriptional Divergence During Human Embryonic Development
The trophoblast cell lineage is specified early at the blastocyst stage, leading to the emergence of the trophectoderm and the pluripotent cells of the inner cell mass. Using a double mRNA amplification technique and a comparison with transcriptome data on pluripotent stem cells, placenta, germinal and adult tissues, we report here some essential molecular features of the human mural trophectoderm. In addition to genes known for their role in placenta (CGA, PGF, ALPPL2 and ABCG2), human trophectoderm also strongly expressed Laminins, such as LAMA1, and the GAGE Cancer/Testis genes. The very high level of ABCG2 expression in trophectoderm, 7.9-fold higher than in placenta, suggests a major role of this gene in shielding the very early embryo from xenobiotics. Several genes, including CCKBR and DNMT3L, were specifically up-regulated only in trophectoderm, indicating that the trophoblast cell lineage shares with the germinal lineage a transient burst of DNMT3L expression. A trophectoderm core transcriptional regulatory circuitry formed by 13 tightly interconnected transcription factors (CEBPA, GATA2, GATA3, GCM1, KLF5, MAFK, MSX2, MXD1, PPARD, PPARG, PPP1R13L, TFAP2C and TP63), was found to be induced in trophectoderm and maintained in placenta. The induction of this network could be recapitulated in an in vitro trophoblast differentiation model
Evolution of Skull and Mandible Shape in Cats (Carnivora: Felidae)
The felid family consists of two major subgroups, the sabretoothed and the feline cats, to which all extant species belong, and are the most anatomically derived of all carnivores for predation on large prey with a precision killing bite. There has been much controversy and uncertainty about why the skulls and mandibles of sabretoothed and feline cats evolved to become so anatomically divergent, but previous models have focused on single characters and no unifying hypothesis of evolutionary shape changes has been formulated. Here I show that the shape of the skull and mandible in derived sabrecats occupy entirely different positions within overall morphospace from feline cats, and that the evolution of skull and mandible shape has followed very different paths in the two subgroups. When normalised for body-size differences, evolution of bite forces differ markedly in the two groups, and are much lower in derived sabrecats, and they show a significant relationship with size and cranial shape, whereas no such relationship is present in feline cats. Evolution of skull and mandible shape in modern cats has been governed by the need for uniform powerful biting irrespective of body size, whereas in sabrecats, shape evolution was governed by selective pressures for efficient predation with hypertrophied upper canines at high gape angles, and bite forces were secondary and became progressively weaker during sabrecat evolution. The current study emphasises combinations of new techniques for morphological shape analysis and biomechanical studies to formulate evolutionary hypotheses for difficult groups
A simulation-based curriculum to introduce key teamwork principles to entering medical students
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