Ferroelectric Phase Transitions in Films with Depletion Charge

We consider ferroelectric phase transitions in both short-circuited and biased ferroelectric-semiconductor films with a space (depletion) charge which leads to some unusual behavior. It is shown that in the presence of the charge the polarization separates into `switchable' and `non-switchable' parts. The electric field, appearing due to the space charge, does not wash out the phase transition, which remains second order but takes place at somewhat reduced temperature. At the same time, it leads to a suppression of the ferroelectricity in a near-electrode layer. This conclusion is valid for materials with both second and first order phase transitions in pure bulk samples. Influence of the depletion charge on thermodynamic coercive field reduces mainly to the lowering of the phase transition temperature, and its effect is negligible. The depletion charge can, however, facilitate an appearance of the domain structure which would be detrimental for device performance (fatigue). We discuss some issues of conceptual character, which are generally known but were overlooked in previous works. The present results have general implications for small systems with depletion charge.Comment: 11 pages, REVTeX 3.1, five eps-figures included in the text. Minor clarifications in the text. To appear in Phys. Rev. B 61, Apr 1 (2000

Pedicled and skeletonized single and bilateral internal thoracic artery grafts and the incidence of sternal wound complications: Insights from the Arterial Revascularization Trial

Objectives: The question of whether skeletonized internal thoracic artery harvesting reduces the incidence of sternal wound complications in comparison with the pedicled technique, in the context of single or bilateral internal thoracic arteries, remains controversial. We studied the impact of the internal thoracic artery harvesting strategy on sternal wound complication in the Arterial Revascularization Trial. Methods: Patients enrolled in the Arterial Revascularization Trial (n = 3102) were randomized to coronary artery bypass grafting with single or bilateral internal thoracic arteries. Sternal wound complication rates were examined according to the harvesting technique that was documented in 2056 patients. The internal thoracic artery harvesting technique, based on the surgeon's preference, resulted in 4 groups: pedicled single internal thoracic artery (n = 607), pedicled bilateral internal thoracic artery (n = 459), skeletonized single internal thoracic artery (n = 512), and skeletonized bilateral internal thoracic artery (n = 478). Propensity scores weighting was used to estimate the impact of the harvesting technique on sternal wound complications. Results: A total of 219 of 2056 patients (10.6%) experienced a sternal wound complication within 1 year from the index operation. Of those, only 25 patients (1.2%) required sternal wound reconstruction. Pedicled bilateral internal thoracic artery (odds ratio [OR], 1.80; 95% confidence interval [CI], 1.23-2.63) but not skeletonized bilateral internal thoracic artery (OR, 1.00; 95% CI, 0.65-1.53) or skeletonized single internal thoracic artery (OR, 0.89; 95% CI, 0.57-1.38) was associated with a significantly increased risk of any sternal wound complications compared with pedicled single internal thoracic artery. Conclusions: The present Arterial Revascularization Trial substudy suggests that, with a skeletonization technique, the risk of sternal wound complication with bilateral internal thoracic artery grafting is similar to that after standard pedicled single internal thoracic artery harvesting, whereas skeletonized single internal thoracic artery harvesting did not add any further benefit when compared with pedicled single internal thoracic artery harvesting

Thrombin inhibitory activity of some polyphenolic compounds

Thrombin, also known as an active plasma coagulation factor II, belongs to the family of serine proteases and plays a crucial role in blood coagulation process. The process of thrombin generation is the central event of the hemostatic process and regulates blood coagulant activity. For this reason, thrombin inhibition is key to successful novel antithrombotic pharmacotherapy. The aim of our present study was to examine the effects of the well-known polyphenolic compounds on the activity of thrombin, by characterization of its interaction with selected polyphenols using different biochemical methods and biosensor BIAcore analyses. Only six compounds, cyanidin, quercetin, silybin, cyanin, (+)-catechin and (−)-epicatechin, of all examined in this study polyphenols caused the inhibition of thrombin amidolytic activity. But only three of the six compounds (cyanidin, quercetin and silybin) changed thrombin proteolytic activity. BIAcore analyses demonstrated that cyanidin and quercetin caused a strong response in the interaction with immobilized thrombin, while cyanin and (−)-epicatechin induced a low response. Lineweaver–Burk curves show that used polyphenol aglycones act as competitive thrombin inhibitors. Our results suggest that polyphenolic compounds might be potential structural bases and source to find and project nature-based, safe, orally bioavailable direct thrombin inhibitors.This work was supported by Grant 545/485 and Grant 506/810 from the University of Lodz

Constitutive modelling of skin ageing

The objective of this chapter is to review the main biomechanical and structural aspects associated with both intrinsic and extrinsic skin ageing, and to present potential research avenues to account for these effects in mathematical and computational models of the skin. This will be illustrated through recent work of the authors which provides a basis to those interested in developing mechanistic constitutive models capturing the mechanobiology of skin across the life course

Rare variants in BNC2 are implicated in autosomal-dominant congenital lower urinary-tract obstruction

Congenital lower urinary-tract obstruction (LUTO) is caused by anatomical blockage of the bladder outflow tract or by functional impairment of urinary voiding. About three out of 10,000 pregnancies are affected. Although several monogenic causes of functional obstruction have been defined, it is unknown whether congenital LUTO caused by anatomical blockage has a monogenic cause. Exome sequencing in a family with four affected individuals with anatomical blockage of the urethra identified a rare nonsense variant (c.2557C>T [p.Arg853(∗)]) in BNC2, encoding basonuclin 2, tracking with LUTO over three generations. Re-sequencing BNC2 in 697 individuals with LUTO revealed three further independent missense variants in three unrelated families. In human and mouse embryogenesis, basonuclin 2 was detected in lower urinary-tract rudiments. In zebrafish embryos, bnc2 was expressed in the pronephric duct and cloaca, analogs of the mammalian lower urinary tract. Experimental knockdown of Bnc2 in zebrafish caused pronephric-outlet obstruction and cloacal dilatation, phenocopying human congenital LUTO. Collectively, these results support the conclusion that variants in BNC2 are strongly implicated in LUTO etiology as a result of anatomical blockage

Ramipril and Risk of Hyperkalemia in Chronic Hemodialysis Patients

Angiotensin converting enzyme (ACE) inhibitors provide well known cardiorenal-protective benefits added to antihypertensive effects in chronic renal disease. These agents are underused in management of patients receiving hemodialysis (HD) because of common concern of hyperkalemia. However, few studies have investigated effect of renin angiotensin aldosterone system (RAAS) blockade on serum potassium in hemodialysis patients. We assessed the safety of ramipril in patients on maintenance HD. We enrolled 28 adult end stage renal disease (ESRD) patients treated by maintenance HD and prescribed them ramipril in doses of 1.25 to 5 mg per day. They underwent serum potassium concentration measurements before ramipril introduction and in 1 to 3 months afterwards. No significant increase in kalemia was found. Results of our study encourage the use of ACE inhibitors in chronically hemodialyzed patients, but close potassium monitoring is mandatory

New distributional data on bryophytes of Poland, 16

This work presents a list of 139 localities for 16 species of liverworts collected in West Pomerania and Silesia (NW and SW Poland)