Electrical Properties of Midwave and Longwave InAs/GaSb Superlattices Grown on GaAs Substrates by Molecular Beam Epitaxy.

In the present work, we report on the in-plane electrical transport properties of midwave (MWIR) and longwave infrared (LWIR) InAs/GaSb type-II superlattices (T2SLs) grown by molecular beam epitaxy (MBE) system on GaAs (001) substrate. The huge lattice mismatch between the T2SL and GaAs substrate is reduced by the growth of GaSb buffer layer based on interfacial misfit array (IMF) technique. In order to compensate the strain in the InAs/GaSb T2SL, we utilized a special shutters sequence to get InSb-like and GaAs-like interfaces. It is found that the MWIR InAs/GaSb T2SL exhibits a p- and n-type conduction at low and high temperatures, respectively. Interestingly, the conduction change temperature is observed to be dependent on the growth temperature. On the other hand, LWIR T2SL conduction is dominated only by electrons. It is important to note that the dominant scattering mechanism in LWIR T2SL at low temperatures is the interface roughness scattering mechanism.

Products of sugar beet processing as raw materials for chemicals and biodegradable polymers.

This paper presents an overview of alternative uses for products of sugar beet processing, especially sucrose, as chemical raw materials for the production of biodegradable polymers. Traditionally, sucrose has not been considered as a chemical raw material, because of its use in the food industry and high sugar prices. Beet pulp and beetroot leaves have also not been considered as raw materials for chemical production processes until recently. However, current changes in the European sugar market could lead to falling demand and overproduction of sucrose. Increases in the production of white sugar will also increase the production of waste biomass, as a result of the processing of larger quantities of sugar beet. This creates an opportunity for the development of new chemical technologies based on the use of products of sugar beet processing as raw materials. Promising methods for producing functionalized materials include the acidic hydrolysis of sugars (sucrose, biomass polysaccharides), the catalytic dehydration of monosaccharides to HMF followed by catalytic oxidation of HMF to FDCA and polymerization to biodegradable polymers. The technologies reviewed in this article will be of interest both to industry and science.

[Angioscopy: a new intraoperative diagnostic and interventional tool for thoracic aortic treatment]. / Angioskopie: Neues intraoperatives diagnostisches und interventionelles Verfahren für die Therapie der thorakalen Aortenerkrankung.

In complex thoracic aortic disease endovascular techniques and the use of hybrid stent grafts enables a combination therapy of the aortic arch and the descending aorta through a median sternotomy. This emphasizes the importance of intraoperative visualization of the descending aorta and its pathologies. Intraoperative angioscopy is a new diagnostic method for the assessment of distal aortic disease and assists in therapeutic decision-making and navigation of endovascular techniques in the descending aorta. This study presents the angioscopic results of 62 patients (mean age 60±12 years, 73% male, 54 aortic dissections, eight aortic aneurysms) during surgery of the thoracic aorta. Visualization of the extent of pathology along the downstream aorta was feasible in all patients. The implantation of a hybrid stent graft prosthesis was assisted by angioscopy in 34 patients and endovascular balloon dilatation of the stent graft was navigated by angioscopy in 11 patients. Angioscopy has become an indispensable tool in the intraoperative treatment of complex thoracic aortic disease in our clinic, particularly in the navigation of endovascular interventions in the distal thoracic aorta through the aortic arch.

Towards trends in minimal invasive cardiac surgery.

While various minimally invasive techniques have been established in many other surgical specialties during the last decades, cardiac surgery has been one of the last domains to adopt the principles of minimally invasive techniques. This was mainly based on the reduced surgical exposure in highly complex cardiac operations and the missing technical requirements in the beginning of the modern cardiac era. Nowadays, technical conditions have continuously improved and have become routine also in cardiac surgery. Most of these novel minimal-invasive concepts have been developed in order to treat high-risk or inoperable patients by reducing operative trauma. Actually, since more high-risk and multimorbid patients were referred for surgery, these initial extraordinary procedures have been adopted into daily clinical routine. Currently, many promising innovations aim to reduce the operative trauma and perioperative morbidity, and furthermore, to increase patients' satisfaction and security. It is anticipated that in the future this current trend towards minimal invasiveness will increase further due to an increased demand, and therefore, such minimal-invasive procedures will become less complex and straightforward.

[Perioperative antocoagulation in patients with prosthetic heart valves: recommendations]. / Perioperatives Gerinnungsmanagement bei Patienten mit Kunstklappen : Empfehlungen.

Lifelong anticoagulation, mainly with oral Vitamin K antagonists, represents the treatment of choice in patients with prosthetic heart valves to prevent thrombembolic complications. As a result, anticoagulant-related complications like excessive bleeding during interventions or surgical procedures will occur. Therefore, timely stopping of vitamin K antagonists prior to elective surgery is mandatory. However, based on the long half-life of all common vitamin K antagonists, interruption of oral anticoagulation will definitively lead to an increase of thrombembolic events. Hence, adequate bridging anticoagulation by temporary substitution of this therapy with heparin is necessary. This article gives a recommendation on the basis of the American College of Chest Physician and European Society of Cardiology current.

The Werner syndrome protein is required for recruitment of chromatin assembly factor 1 following DNA damage.

The Werner syndrome protein (WRN) and chromatin assembly factor 1 (CAF-1) are both involved in the maintenance of genome stability. In response to DNA-damaging signals, both of these proteins relocate to sites where DNA synthesis occurs. However, the interaction between WRN and CAF-1 has not yet been investigated. In this report, we show that WRN interacts physically with the largest subunit of CAF-1, hp150, in vitro and in vivo. Although hp150 does not alter WRN catalytic activities in vitro, and the chromatin assembly activity of CAF-1 is not affected in the absence of WRN in vivo, this interaction may have an important role during the cellular response to DNA replication fork blockage and/or DNA damage signals. In hp150 RNA-mediated interference (RNAi) knockdown cells, WRN partially formed foci following hydroxyurea (HU) treatment. However, in the absence of WRN, hp150 did not relocate to form foci following exposure to HU and ultraviolet light. Thus, our results demonstrate that WRN responds to DNA damage before CAF-1 and suggest that WRN may recruit CAF-1, via interaction with hp150, to DNA damage sites during DNA synthesis.

The last deglaciation of the southeastern sector of the Scandinavian ice sheet.

The Scandinavian Ice Sheet (SIS) was an important component of the global ice sheet system during the last glaciation, but the timing of its growth to or retreat from its maximum extent remains poorly known. We used 115 cosmogenic beryllium-10 ages and 70 radiocarbon ages to constrain the timing of three substantial ice-margin fluctuations of the SIS between 25,000 and 12,000 years before the present. The age of initial deglaciation indicates that the SIS may have contributed to an abrupt rise in global sea level. Subsequent ice-margin fluctuations identify opposite mass-balance responses to North Atlantic climate change, indicating differing ice-sheet sensitivities to mean climate state.

Impact of intraoperative myocardial cellular damage on early hemodynamics after off-pump versus on-pump coronary artery bypass surgery.

BACKGROUND: Due to the surgical trauma a small amount of myocardial cellular damage is inherent during coronary artery bypass grafting (CABG). The purpose of the present study was to assess the degree of myocardial cellular damage after off-pump (OPCAB) and on-pump CABG (ONCAB) as measured by cardiac troponin I (cTnI), creatine kinase (CK), its MB isoenzyme (CK-MB) and myoglobin (Myo) and to examine its impact on early hemodynamics after surgery. METHODS: Ninety-nine consecutive OPCAB patients, operated between 01/1999 and 01/2004, were enrolled in the present study and compared to 99 ONCAB patients operated during the same period of time, who were matched for baseline data and mean number of grafts per patient. Early hemodynamics, cTnI, CK/CK-MB and Myo were measured preoperatively and at 1, 6, 12, 24 and 48 hours (h) postoperatively. Perioperative inotropic support, clinical data and potoperative outcome were recorded prospectively. RESULTS: The two groups were similar concerning preoperative characteristics. The mean number of distal grafts/patient was 2.1 +/- 1.0 in OPCAB and 2.1 +/- 0.8 in ONCAB patients (mean +/- SD). There was no significant difference among the groups regarding early hemodynamics in terms of cardiac index (CI), systemic vascular resistance index (SVRI), and left ventricular stroke work index (LVSWI), and inotropic support. However, cTnI, CK/CK-MB but not Myo levels were significantly lower in OPCAB compared to ONCAB patients at 1, 6, 12, 24, 36 and 48 h postoperatively (P<0.05). CONCLUSIONS: Off-pump surgery results in equal early hemodynamics despite a significantly lower release of cTnI and CK, suggesting a reduced myocardial cell damage as compared to ONCAB surgery.

Heart transplantation and consecutive mitral valve replacement.

A 48-year-old man was diagnosed with progressive mitral insufficiency due to fibrosis of papillary muscles and chordae tendineae, necessitating mitral valve replacement (MVR) 8 months after cardiac transplantation. Donor echocardiography and inspection of the heart at procurement were inconspicuous. The patient is alive, free from valve-related complications and functionally improved six years after MVR. The limited yet successful experiences with left-sided valve repair or replacement in the transplanted heart are reviewed.

Severe left ventricular failure after double lung transplantation: pathophysiology and management.

Patients undergoing bilateral lung transplantation for end-stage pulmonary hypertension may experience various complications. We describe a patient who underwent transplantation for chronic pigeon breeder's disease, who had secondary pulmonary hypertension and deteriorated right heart function, and who developed severe left heart failure during the weaning phase after successful double lung transplantation. The patient was stabilized with catecholamines and an intra-aortic balloon pump. Left heart function increased within 7 days and normalized at Day 18. Otherwise, the post-operative course was uneventful.

The effects of arbuscular mycorrhizas on soil aggregation depend on the interaction between plant and fungal species.

• Arbuscular mycorrhizal fungi (AMF) and roots mediate soil stabilization, although the mechanisms and how their interactions affect soil stabilization are not known. We tested the effects of specific plant-fungus combinations on aggregate stabilization, and whether hyphal length and root biomass determine stabilization, predicting that fungi producing more hyphae, and plants with higher root biomasses, would better stabilize soils. • The percentage of water-stable aggregates (%WSA1-2 mm ), hyphal lengths, and root biomass were measured from a five AMF × nine plant factorial experiment. Arbuscular mycorrhizal fungi with greater extradical mycelium production were represented by the Gigasporaceae and plants of high root biomass by grasses. Other taxa represented lower hyphal lengths and root biomass. • An interaction between symbionts with respect to %WSA1-2 mm was observed. Root biomass and total hyphal lengths were not positively correlated with %WSA. Combinations of grasses with Gigasporaceae fungi had the lowest %WSA. • Mechanisms underlying aggregation were not elucidated by measuring root biomass and total hyphal lengths alone, suggesting other physiological or architectural mechanisms may be responsible.

Efficacy and safety of single-triple capsules of bismuth biskalcitrate, metronidazole and tetracycline, given with omeprazole, for the eradication of Helicobacter pylori: an international multicentre study.

BACKGROUND: The high prevalence of Helicobacter pylori resistance to metronidazole demands treatments more effective than standard bismuth-based triple therapy against these strains. AIM: To evaluate the H. pylori eradication rate in both metronidazole-sensitive and -resistant strains following quadruple therapy using single-triple capsules of bismuth biskalcitrate, metronidazole and tetracycline, given with omeprazole. METHODS: One hundred and seventy valid patients with duodenal ulcer, gastric ulcer or non-ulcer dyspepsia were treated in eight centres located in five countries. H. pylori was confirmed at baseline using 13C-urea breath test, histology and/or culture. Patients received three single-triple capsules q.i.d. and omeprazole, 20 mg b.d., for 10 days. Each capsule contained bismuth biskalcitrate, 140 mg (as 40 mg Bi2O3 equivalent), metronidazole, 125 mg, and tetracycline, 125 mg. 13C-Urea breath test was repeated at least 4 and 8 weeks post-treatment. RESULTS: Overall eradication rates were 93% (158/170) by modified intention-to-treat analysis and 97% (142/146) by per protocol analysis. Eradication rates were 93% (40/43) and 95% (38/40) for strains resistant to metronidazole and 95% (82/86) and 99% (75/76) for strains sensitive to metronidazole by modified intention-to-treat and per protocol analysis, respectively. CONCLUSION: This omeprazole-bismuth biskalcitrate-metronidazole-tetracycline 10-day regimen is a very effective and well-tolerated treatment, which overcomes metronidazole resistance.

Up-regulation of gastric mucosal inflammatory responses to Helicobacter pylori lipopolysaccharide by aspirin but not indomethacin.

Infection with Helicobacter pylori and the use of non-steroidal anti-inflammatory drugs (NSAIDs) are recognized as the two primary factors in the etiology of gastric disease. In this study, we applied the animal model of H. pylori-induced gastritis to assess the influence of NSAIDs on the course of mucosal inflammatory responses to H. pylori. Two days following intragastric application of H. pylori lipopolysaccharide, rats were divided into groups and administered daily for up to 8 days either indomethacin, aspirin or the vehicle, and their gastric mucosal tissue subjected to histological and biochemical assessment. H. pylori lipopolysaccharide elicited within 2 days a pattern of acute mucosal inflammatory responses accompanied by a massive epithelial cell apoptosis, and a marked increase in the expression of membrane-bound and soluble forms of TNF-alpha. The extent of mucosal inflammatory involvement reached a maximum by the 4th day and showed a decline by the 10th day; this was reflected in a 38.1% reduction in apoptosis, a 53.2% decline in membrane-bound TNF-alpha and a 63.8% decrease in soluble TNF-alpha. Compared to the vehicle controls, aspirin caused a 36.2% increase in the severity of the mucosal inflammatory involvement by the second day of administration and a 25.9% increase in the inflammatory involvement occurred by the 8th day; this effect of aspirin was accompanied by a significant (54.5%) induction in apoptosis, a 58.2% decline in membrane-bound TNF-alpha and a 61% increase in soluble TNF-alpha. In contrast, administration of indomethacin evoked only a marginal increase (5-7%) in apoptosis, and caused no discernible changes in the severity of gastric mucosal involvement and the expression of TNF-alpha forms elicited by H. pylori lipopolysaccharide. The findings indicate that aspirin, but not indomethacin, increases the severity of gastric mucosal inflammatory responses to H. pylori. This detrimental influence of aspirin appears to result from up-regulation in the mucosal expression of soluble form of TNF-alpha, which leads to the amplification of apoptotic events that potentiate gastric mucosal inflammatory reaction to H. pylori.

[Surgical treatment of infective endocarditis: the Essen experiences]. / Die chirurgische Therapie der infektiösen Endokarditis: Essener Erfahrungen.

BACKGROUND: Instead of immediate diagnosis and effective antibiotic treatment morbidity and mortality in infective endocarditis remains high. If the infection cannot be controlled or the disease progresses irreversible destruction of cardiac structures results. SURGICAL THERAPY: In this case surgical therapy should be considered immediately. The outcome of surgical repair is not depending on the implanted prosthesis, but solely on timing of the operation.

Werner syndrome protein interacts with human flap endonuclease 1 and stimulates its cleavage activity.

Werner syndrome (WS) is a human premature aging disorder characterized by chromosomal instability. The cellular defects of WS presumably reflect compromised or aberrant function of a DNA metabolic pathway that under normal circumstances confers stability to the genome. We report a novel interaction of the WRN gene product with the human 5' flap endonuclease/5'-3' exonuclease (FEN-1), a DNA structure-specific nuclease implicated in DNA replication, recombination and repair. WS protein (WRN) dramatically stimulates the rate of FEN-1 cleavage of a 5' flap DNA substrate. The WRN-FEN-1 functional interaction is independent of WRN catalytic function and mediated by a 144 amino acid domain of WRN that shares homology with RecQ DNA helicases. A physical interaction between WRN and FEN-1 is demonstrated by their co-immunoprecipitation from HeLa cell lysate and affinity pull-down experiments using a recombinant C-terminal fragment of WRN. The underlying defect of WS is discussed in light of the evidence for the interaction between WRN and FEN-1.

A functional interaction of Ku with Werner exonuclease facilitates digestion of damaged DNA.

Werner syndrome (WS) is a premature aging disorder where the affected individuals appear much older than their chronological age. The single gene that is defective in WS encodes a protein (WRN) that has ATPase, helicase and 3'-->5' exonuclease activities. Our laboratory has recently uncovered a physical and functional interaction between WRN and the Ku heterodimer complex that functions in double-strand break repair and V(D)J recombination. Importantly, Ku specifically stimulates the exonuclease activity of WRN. We now report that Ku enables the Werner exonuclease to digest through regions of DNA containing 8-oxoadenine and 8-oxoguanine modifications, lesions that have previously been shown to block the exonuclease activity of WRN alone. These results indicate that Ku significantly alters the exonuclease function of WRN and suggest that the two proteins function concomitantly in a DNA damage processing pathway. In support of this notion we also observed co-localization of WRN and Ku, particularly after DNA damaging treatments.