Impact of Correlated Disorder on Surface Superconductivity: Revealing the Robustness of the Surface Ordering Effect.

Surface superconductivity, wherein electron pairing occurs at material surfaces or interfaces, has attracted a remarkable amount of attention since its discovery. Recent theoretical predictions have unveiled increased critical temperatures, especially at the surfaces of certain compounds and/or structures. The notion of "surface ordering" has been advanced to elucidate this phenomenon. Employing the framework of self-consistent Bogoliubov-de Gennes equations and a model incorporating correlated disorder, our study demonstrates the persistence of the surface ordering effect in the presence of weak to moderate bulk disorder. Intriguingly, our findings indicate that under moderate disorder conditions the surface critical temperature can be further increased, depending on the intensity and correlation of the disorder.

Effect of Material-Dependent Boundaries on the Interference Induced Enhancement of the Surface Superconductivity Temperature.

Using the tight-binding Bogoliubov-de Gennes formalism, we describe the influence of the surface potential on the superconducting critical temperature at the surface. Surface details are taken into account within the framework of the self-consistent Lang-Kohn effective potential. The regimes of strong and weak coupling of superconducting correlations are considered. Our study reveals that, although the enhancement of the surface critical temperature, originating from the enhancement of the localized correlation due to the constructive interference between quasiparticle bulk orbits, can be sufficiently affected by the surface potential, this influence, nonetheless, strongly depends on the bulk material parameters, such as the effective electron density parameter and Fermi energy, and is likely to be negligible for some materials, in particular for narrow-band metals. Thus, superconducting properties of a surface can be controlled by the surface/interface potential properties, which offer an additional tuning knob for the superconducting state at the surface/interface.

Superanomalous skin-effect and enhanced absorption of light scattered on conductive media.

Light scattering spectroscopy is a powerful tool for studying various media, but interpretation of its results requires a detailed knowledge of how media excitations are coupled to electromagnetic waves. In electrically conducting media, an accurate description of propagating electromagnetic waves is a non-trivial problem because of non-local light-matter interactions. Among other consequences, the non-locality gives rise to the anomalous (ASE) and superanomalous (SASE) skin effects. As is well known, ASE is related to an increase in the electromagnetic field absorption in the radio frequency domain. This work demonstrates that the Landau damping underlying SASE gives rise to another absorption peak at optical frequencies. In contrast to ASE, SASE suppresses only the longitudinal field component, and this difference results in the strong polarization dependence of the absorption. The mechanism behind the suppression is generic and is observed also in plasma. Neither SASE, nor the corresponding light absorption increase can be described using popular simplified models for the non-local dielectric response.

Multiband superconductors with degenerate excitation gaps.

There is a tacit assumption that multiband superconductors are essentially the same as multigap superconductors. More precisely, it is usually assumed that the number of excitation gaps in the single-particle energy spectrum of a uniform superconductor (i.e. number of peaks in the density of states of the superconducting electrons) determines the number of contributing bands in the corresponding superconducting model. Here we demonstrate that contrary to this widely accepted viewpoint, the superconducting magnetic properties are sensitive to the number of contributing bands even when the spectral gaps are degenerate and cannot be distinguished. In particular, we find that the crossover between superconductivity types I and II-the intertype regime-is strongly affected by the difference between characteristic lengths of multiple contributing condensates. The reason for this is that condensates with diverse characteristic lengths, when coexisting in one system, interfere constructively or destructively, which results in multi-condensate magnetic phenomena regardless of the presence/absence of the multigap spectrum of a superconducting multiband material.

Superanomalous Skin Effect for Surface Plasmon Polaritons.

It is commonly assumed that surface plasmon-polariton (SPP) excitations on a metal-dielectric interface decay exponentially inside the metallic sample. Here, we show that in a wide spectral interval the SPP field decays much slower, being inversely proportional to the distance to the interface modified by an additional logarithmic factor. This dependence differs from the standard anomalous skin effect and is provisionally referred to as superanomalous. Its origin is the nonlocality and the logarithmic singularity of the dielectric permittivity in metals. This type of decay is pronounced for SPP modes of higher frequencies, but it is suppressed for light waves.

[Polyphenolic compounds analysis and antioxidant activity in fruits of Prunus spinosa L.] / Not available.

INTRODUCTION: Prunus spinosa L. (blackthorn, sloe) is a com- mon species in the wild flora of Europe. Marmalade, syrup, and alcoholic beverages have been prepared from fruits. In folk medicine they'are used due to the astringent effect. However there are few studies on these indigenous fruits. According to the literature they contain tannins, anthocyanins, sugars, vitamin C etc. METHODS: Our objective is to determine the antioxidant activity as related to their phenolic composition. For this purpose we prepared extracts using methanol, methanol-water (1: 1) and water. The antioxidant activity was determined by DPPH method and by photochemiluminescens (PCL) method. The total polyphenols, total anthocyanins and flavonoids were determined by colorimetric methods. Individual polyphenols were identified by a RP-HPLC-UVIVIS method. RESULTS: The antioxidant activity decreased in the extracts as follows: methanol > methanol-water > water (IC50= 1.33 mg/ml for DPPH; 11.94 µmol AAEIml for PCL > IC50 = 1.87 mg/ml for DPPH; 10.35 µmol AAElml for PCL > IC50 = 15.29 mg/ml for DPPH, 1.89 µmol AAElml for PCL) which is cor- related with the total polyphenol content (369 mg/100g > 244 mg1100g > 101 mg1100g) and total anthocyanin content (37.11 mg/100 g > 16.33 mg/100g > 7.76 mg/100g). The fla- vonoid content is similar in the three extracts (between 35.82 - 37.32 mg1100 g). The HPLC analysis shows high chloro- genic and neochlorogenic acid levels, followed by glycosides of quercetin. CONCLUSIONS: Our results demonstrated that blackthorn fruits are a rich source of phenolic compounds, with anti- oxidant activity, which are best extracted with methanol or methanol-water.

ST Segment Elevation Myocardial Infarction Due to Severe Ostial Left Main Stem Stenosis in a Patient with Syphilitic Aortitis.

Cardiovascular manifestations of tertiary syphilis infections are uncommon, but represent an important cause of mortality and morbidity. Syphilitic aortitis is characterized by aortic regurgitation, dilatation of ascending aorta and ostial coronary artery lesions. We report a case of 36 years old man admitted to our hospital for acute anterior ST segment elevation myocardial infarction complicated with cardiogenic shock (hypotension 75/50 mmHg). Transthoracic echocardiography revealed a dilated left ventricle with severe systolic dysfunction (ejection fraction = 25%), severe mitral regurgitation, moderate aortic regurgitation and mildly dilated ascending aorta. Coronary angiography showed a severe ostial lesion of left main coronary artery which was treated by urgent stent implantation and an intra-aortic contrapulsation balloon was implanted. Blood tests for syphilitic infection were positive. The patient was discharged with treatment including benzathine penicillin. In our case, we present an acute manifestation of a syphilitic ostial left main stenosis treated by primary percutaneous coronary intervention in acute myocardial infarction. Long term follow-up of the patient is crucial as a result of potential rapid in-stent restenosis caused by continuous infection of the ascending aorta. This case is particular because it shows that syphilitic aortitis can be diagnosed in acute settings, like ST segment elevation myocardial infarction.

Phonon limited superconducting correlations in metallic nanograins.

Conventional superconductivity is inevitably suppressed in ultra-small metallic grains for characteristic sizes smaller than the Anderson limit. Experiments have shown that above the Anderson limit the critical temperature may be either enhanced or reduced when decreasing the particle size, depending on the superconducting material. In addition, there is experimental evidence that whether an enhancement or a reduction is found depends on the strength of the electron-phonon interaction in the bulk. We reveal how the strength of the e-ph interaction interplays with the quantum-size effect and theoretically obtain the critical temperature of the superconducting nanograins in excellent agreement with experimental data. We demonstrate that strong e-ph scattering smears the peak structure in the electronic density-of-states of a metallic grain and enhances the electron mass, and thereby limits the highest Tc achievable by quantum confinement.

The Fulde-Ferrell-Larkin-Ovchinnikov state in layered d-wave superconductors: in-plane anisotropy and resonance effects in the angular dependence of the upper critical field.

We study the anisotropy of the in-plane upper critical magnetic field coupled to the orbital motion and the spins of electrons in a layered d(x2-y2) organic superconductor in the spatially modulated Fulde-Ferrell-Larkin-Ovchinnikov phase. We show that the interplay between the nodal structure of the order parameter and its spatial modulation results in the very peculiar angular dependence of the onset of superconductivity in the high-field regime. The principal axis of the field-direction dependence of the onset of superconductivity is tilted by π/4 in the temperature range 0.056 < or approximately equal T < 0.56. In some cases the resonance between the modulation wavevector and the vector potential of a parallel magnetic field may lead to anomalous cusps in the temperature and in-plane angular dependences of the onset of superconductivity. The obtained results support the interpretation of the recent experiments as evidence of the FFLO state.

Fibromuscular dysplasia--a rare cause of renovascular hypertension. Case study and overview of the literature data.

Renal artery stenosis (RAS) is associated with increased cardiovascular mortality and morbidity and may constitute a treatable cause of secondary hypertension. Fibromuscular dysplasia is frequently affecting children as the main cause of RAS, but is very rare in adults. We present the case of a 19-year-old overweight patient, with no known pathological conditions in her medical history or family background, admitted for severe, pulsing headaches during the past 3 months and increased blood pressure (BP) values for about a month (maximum BP 220/140 mmHg). The initial clinical exam and first-line imagistic methods did not provide a high suspicion for RAS. However, the invasive methods established the diagnosis of right renal artery medial dysplasia. Balloon angioplasty was the treatment of choice.

In-plane magnetic field anisotropy of the Fulde-Ferrell-Larkin-Ovchinnikov state in layered superconductors.

There is strong experimental evidence of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state formation in layered organic superconductors in a parallel magnetic field. We study theoretically the interplay between the orbital effect and the FFLO modulation in this case and demonstrate that the in-plane critical field anisotropy drastically changes at the transition to the FFLO state. The very peculiar angular dependence of the superconducting onset temperature which is predicted may serve for unambiguous identification of the FFLO modulation. The obtained results permit us to suggest the modulated phase stabilization as the origin of the magnetic-field angle dependence of the onset of superconductivity experimentally observed in (TMTSF)2ClO4 organic conductors.

Quantum cascades in nano-engineered superconductors: geometrical, thermal and paramagnetic effects.

The effect of a parallel magnetic field on the orbital motion of electrons in high-quality superconducting nanowires resulting in a superconductor-to-normal transition which occurs through a cascade of jumps in the order parameter as a function of the magnetic field. Such cascades originate from the transverse size quantization that splits the conduction band into a series of subbands. Here, based on a numerical solution of the Bogoliubov-de Gennes equations for a hollow nanocylinder, we investigate how the quantum-size cascades depend on the confining geometry, i.e., by changing the cylinder radius R and its thickness d we cover the range from the nanowire-like to the nanofilm-like regime. The cascades are shown to become much less pronounced when increasing R/d, i.e., when the nanofilm-like regime is approached. When the temperature is non-zero they are thermally smoothed. This includes the spin-magnetic-field interaction which reduces the critical (depairing) parallel magnetic field H(c,//) but does not have any qualitative effect on the quantum cascades. From our calculations it is seen that the paramagnetic limiting field H(par) significantly exceeds H(c,//) even in extremely narrow nanocylinders, i.e., when R,d are down to a few nanometers, and H(c,//) is only about 10% larger when switching-off the spin-magnetic-field interaction in this case. Both characteristic fields, H(c,//) and H(par), exhibit pronounced quantum-size oscillations. We demonstrate that the quantum cascades and the quantum-size oscillations survive in the presence of surface roughness.

Ultra-small metallic grains: effect of statistical fluctuations of the chemical potential on superconducting correlations and vice versa.

Superconducting correlations in an isolated metallic grain are governed by the interplay between two energy scales: the mean level spacing δ and the bulk pairing gap Δ0, which are strongly influenced by the position of the chemical potential with respect to the closest single-electron level. In turn superconducting correlations affect the position of the chemical potential. Within the parity projected BCS model we investigate the probability distribution of the chemical potential in a superconducting grain with randomly distributed single-electron levels. Taking into account statistical fluctuations of the chemical potential due to the pairing interaction, we find that such fluctuations have a significant impact on the critical level spacing δc at which the superconducting correlations cease: the critical ratio δc/Δ0 at which superconductivity disappears is found to be increased.

[Liver transplantation--indications, surgical technique, results--the analysis of a clinical series of 200 cases]. / Transplantul hepatic--indicati, tehnica, rezultate-analiza unei serii clinice de 200 de cazuri.

INTRODUCTION: Initially considered experimental, liver transplantation (LT) has become the treatment of choice for the patients with end-stage liver diseases. MATERIAL AND METHODS: Between April 2000 and October 2009, 200 LTs (10 reLTs) were performed in 190 patients, this study being retrospective. There were transplanted 110 men and 80 women, 159 adults and 31 children with the age between 1 and 64 years old (mean age--39.9). The main indication in the adult group was represented by viral cirrhosis, while the pediatric series the etiology was mainly glycogenosis and biliary atresia. There were performed 143 whole graft LTs, 46 living donor LTs, 6 split LTs, 4 reduced LTs and one domino LT RESULTS: The postoperative survival was 90% (170 patients). The patient and graft one-year and five-year survivals were 76.9%, 73.6% and 71%, 68.2%, respectively. The early complications occurred in 127 patients (67%). The late complications were recorded in 71 patients (37.3%). The intraoperative and early postoperative mortality rate was 9.5% (18 patients). CONCLUSIONS: The Romanian liver transplantation program from Fundeni includes all types of current surgical techniques and the results are comparable with those from other international centers.

Mesenteric ischemia--a complex disease requiring an interdisciplinary approach. A review of the current literature.

Mesenteric ischemia is caused by a reduction in intestinal blood flow with potential catastrophic clinical consequences: sepsis, bowel infarction, and death. In the recent years, the incidence of mesenteric ischemia increased, now accounting for 0.1% of hospital admissions. Among the multiple factors responsible for this change is the heightened awareness for the diagnoses, the advanced mean age of the population and the increasing number of critically ill patients. Acute mesenteric ischemia is a potentially fatal vascular emergency, with overall mortality of 60-80%; prompt diagnosis and treatment are paramount. A high index of suspicion in the setting of a compatible history and physical examination serves as the cornerstone to early diagnosis of mesenteric ischemia. Restoration of intestinal blood flow, as rapidly as possible, is the main goal of treatment in patients with acute mesenteric ischemia. This may be achieved by medical means, endovascular procedures and by surgery. Chronic mesenteric ischemia is an uncommon process that occurs only when severe atherosclerotic narrowing of a major splanchnic vessel exists in association with occlusion of one or two of the remaining vessels. Its diagnosis is mainly based on the characteristic clinical picture, on the presence of an occlusive lesion in the splanchnic vessels and on the absence of other common causes of abdominal pain. The means available for mesenteric revascularization are the surgical techniques of flow restoration and the more recently developed percutaneous transluminal procedures.

Cardiac involvement in myasthenia gravis--is there a specific pattern?

Myasthenia gravis is an autoimmune neuromuscular disorder characterized by skeletal muscle involvement, causing muscle weakness and fatigue. The prevalence of the disease is approximately 1:7500 with a maximal prevalence during the second and third decade in women and the fifth and sixth decade in men, although it may appear at any age. The disease has a slight female preponderance, with a sex ratio of 3:2. Cardiac involvement in myasthenia gravis may take several forms, ranging from asymptomatic ECG changes to ventricular tachycardia, myocarditis, conduction disorders, heart failure and sudden death. We hereby report two cases of patients with myasthenia gravis who developed signs and symptoms of cardiovascular involvement, requiring admission in a cardiology ward for further investigation and treatment. The particular characteristics of the first case may be summarized by the symptomatic conduction disturbances with frequent episodes of syncope in a patient with myasthenia gravis who necessitated permanent pacing and the difficulties we encountered in the establishment of conduction disturbancies etiology (due to the disease or due to the treatment with acetylcolinesterase inhibitors). The second case shows a different kind of cardiac involvement in myasthenia gravis--the ECG changes (giant diffuse T waves in a patient with cardiovascular risk factors) which needed further investigation and long term surveillance.

Superconducting nanowires: quantum confinement and spatially dependent Hartree-Fock potential.

It is well known that, in bulk, the solution of the Bogoliubov-de Gennes equations is the same whether or not the Hartree-Fock term is included. Here the Hartree-Fock potential is position independent and so gives the same contribution to both the single-electron energies and the Fermi level (the chemical potential). Thus, the single-electron energies measured from the Fermi level (they control the solution) stay the same. This is not the case for nanostructured superconductors, where quantum confinement breaks the translational symmetry and results in a position-dependent Hartree-Fock potential. In this case its contribution to the single-electron energies depends on the relevant quantum numbers. We numerically solved the Bogoliubov-de Gennes equations with the Hartree-Fock term for a clean superconducting nanocylinder and found a shift of the curve representing the thickness-dependent oscillations of the critical superconducting temperature to larger diameters.

Risk profile in women with acute myocardial infarction.

The studies in the literature of the past years have noticed the particular characteristics of the ischemic heart disease in women, who seem to be lacking early diagnosis and invasive treatment of coronary heart disease. They especially emphasize that the evolution, complications and mortality in myocardial infarction in women are more severe. THE GOAL OF THE STUDY: The evaluation of clinical, investigational and therapeutic aspects in a lot of women with acute myocardial infarction (AMI) versus a lot of men with the same pathology, hospitalised in the same period. MATERIAL AND METHODS: 78 women hospitalised in the Emergency Institute of Cardiovascular Diseases between 1st January 1999 and 30th October 2001 with acute myocardial infarction. 109 men hospitalised in the Emergency Institute of Cardiovascular Diseases with acute myocardial infarction in the same period. INCLUSION CRITERIA: acute myocardial infarction, coronary angiography +/=left ventriculography. The lot of study and the witness lot were divided into 3 subgroups based on the severity of coronary lesions: Group I: left main stenoses, Group II: stenoses >60% on the other epicardial coronary vessels, Group III: stenoses <60% on the other epicardial coronary vessels. The risk factors, clinical data, cardiac performance indices and medical and invasive treatment were compared between the two groups. RESULTS/CONCLUSIONS: The women hospitalised with AMI were older than men, had more diabetes and hypertension as main risk factors than men, with the exception of smoking, had more frequent heart failure and diastolic dysfunction of left ventricle. The favorite invasive treatment in women was the angioplasty with application of stent and in men--coronary bypass.

Measurement of specimen thickness by phase change determination in TEM.

A non-destructive method for measuring the thickness of thin amorphous films composed of light elements has been developed. The method employs the statistics of the phase of the electron exit wave function. The accuracy of this method has been checked numerically by the multislice method and compared with that based on the mean inner potential.

Pathological features of colorectal carcinomas in MYH-associated polyposis.

AIMS: MYH is a DNA glycosylase in the base excision repair pathway. Germ-line biallelic mutations in the MYH gene are associated with the development of multiple colorectal adenomas and colorectal carcinoma (CRC). A slightly increased risk of CRC is suggested in monoallelic MYH mutation carriers. The aim was to characterize the histopathological features of carcinomas from biallelics and monoallelics. METHODS AND RESULTS: Clinicopathological features of 57 colorectal carcinomas from 50 patients identified in familial CRC registries were recorded. These included 16 cancers from 14 MYH biallelics; 25 cancers from 22 MYH monoallelics; and 16 cancers from 14 controls. Carcinomas in biallelics demonstrated tubular, papillary or cribriform patterns as the predominant histological subtype, and main histological groups differed according to mutation status (P = 0.0053). All biallelic cancers were low grade, with high-grade tumours more common in monoallelics and controls (P = 0.002). Synchronous polyps were observed in 75% of biallelics, 33% of monoallelics and 43% of controls (P = 0.035). Serrated carcinoma was the predominant type in 12% (3/25) of the monoallelics but in none of the biallelics or controls. MYH immunohistochemistry failed to distinguish between groups. CONCLUSIONS: Neither pathological features nor immunohistochemistry could predict the MYH mutation status of CRCs in this study.