68 research outputs found
Direct Observation of Interband Spin-Orbit Coupling in a Two-Dimensional Electron System
We report the direct observation of interband spin-orbit (SO) coupling in a
two-dimensional (2D) surface electron system, in addition to the anticipated
Rashba spin splitting. Using angle-resolved photoemission experiments and
first-principles calculations on Bi/Ag/Au heterostructures we show that the
effect strongly modifies the dispersion as well as the orbital and spin
character of the 2D electronic states, thus giving rise to considerable
deviations from the Rashba model. The strength of the interband SO coupling is
tuned by the thickness of the thin film structures
The Critical Role of PPARγ in Human Malignant Melanoma
The past 30 years have only seen slight improvement in melanoma therapy. Despite a wide variety of therapeutic options, current survival for patients with metastatic disease is only 6–8 months. Part of the reason for this treatment failure is the broad chemoresistance of melanoma, which is due to an altered survival capacity and an inactivation of apoptotic pathways. Several targetable pathways, responsible for this survival/apoptosis resistance in melanoma, have been described and current research has focused on mechanism inactivating these pathways. As PPARγ was shown to be constitutively active in several tumour entities and PPARγ agonists extent strong anticancer effects, the role of PPARγ as a possible target for specific anticancer strategy was investigated in numerous studies. However, only a few studies have focused on the effects of PPARγ agonists in melanoma, showing conflicting results. The use of PPARγ agonists in melanoma therapy has to be
carefully weighted against considerable,
undesirable side effects, as their mode of action is not fully
understood and even pro-proliferative effects have
been described. In the current review, we discuss the role of
PPARs, in particular PPARγ in melanoma and their potential role as a molecular target for melanoma therapy
Социально-философский анализ процессов модернизации в Китайской Народной Республике
Проанализированы основные изменения, произошедшие в обществе, в политической системе Китая в связи с началом реформ и модернизации после прихода к власти Дэн Сяопина. Дан анализ основных положений программы модернизации, предложенной руководством КНР. Освещены теоретико-методологические предпосылки модернизации КНР. Выделены основные мировоззренческие и методологические элементы теории социализма с китайской специфики
Objective Response to Radiation Therapy and Long-Term Survival of Patients with WHO Grade II Astrocytic Gliomas with Known LOH 1p/19q Status
Background:: WHO grade II gliomas are often approached by radiation therapy (RT). However, little is known about tumor response and its potential impact on long-term survival. Patients and Methods:: Patients subjected to RT were selected from the own database of WHO grade II gliomas diagnosed between 1991 and 2000. The volumetric tumor response after RT was assessed based on magnetic resonance imaging and graded according to standard criteria as complete, partial (PR, ≥ 50%), or minor (MR, 25% to < 50%). Results:: There were 24 astrocytomas and three oligoastrocytomas. 21 patients (78%) were dead at follow-up (mean survival 74 months). None of the patients had chemotherapy. Objective response occurred in 14 patients (52%, five PR and nine MR) but was not associated with overall survival. The vast majority of the tumors had no loss of heterozygosity (LOH) 1p and/or 19q (86%). Conclusion:: Approximately 50% of patients with astrocytic WHO grade II gliomas respond to RT despite the absence of LOH for 1p/19q. The potential predictive factors for response and the impact of response on overall survival remain unclea
Разработка системы УФ-освещения для люминесцентного метода капиллярного контроля
В процессе исследования производилась разработка УФ-облучателя на основе эксилампы для люминесцентного капиллярного контроля с целью достижения оптимальных параметров соответствующих конкретным задачам в
проведении люминесцентного метода контроля:
– изменение длины волны, путем подбора определенной газовой смеси и
условий, в которых реализуется электрический разряд;
– увеличения ресурса работы;
– портативность, поскольку эксилампа обладает небольшим весом,
имеется возможность модернизации ее до портативной версии, работающей от
батареи;
– эргономичность – доработка корпуса путем изменения геометрии
корпуса и материалов, а также разработка крепления и формы ручки для легкой
эксплуатации.The object of the study is a portable exciplex barrier-discharge lamp (XeCl).
The aim of this work is to develop a UV exciter based on an exclamp for the luminescence method of capillary control.
In the process of research, the effective development of a UV irradiator based on an exclamp for luminescent capillary monitoring in order to achieve the optimum parameters of the corresponding task in conducting luminescence method of capillary control:
- change in the wavelength, under the selection of a specific gas mixture and the conditions in which an electric discharge is realized;
- increase in the resource of work;
- Portability, because the excilamp has a small weight, it is possible to upgrade it to a portable version powered by a battery
Restenosis after microsurgical non-patch carotid endarterectomy in 586 patients
Background: Carotid endarterectomy (CEA) reduces the risk of stroke in patients with symptomatic (>50%) and asymptomatic (>60%) carotid artery stenosis. Here we report the midterm results of a microsurgical non-patch technique and compare these findings to those in the literature. Methods: From 1998 to 2009 we treated 586 consecutive patients with CEA. CEA was performed, under general anesthesia, with a surgical microscope using a non-patch technique. Somatosensory evoked potential and transcranial Doppler were continuously monitored. Cross-clamping was performed under EEG burst suppression and adaptive blood pressure increase. Follow-up was performed by an independent neurologist. Mortality at 30 days and morbidity such as major and minor stroke, peripheral nerve palsy, hematoma and cardiac complications were recorded. The restenosis rate was assessed using duplex sonography 1 year after surgery. Results: A total of 439 (75%) patients had symptomatic and 147 (25%) asymptomatic stenosis; 49.7% of the stenoses were on the right-side. Major perioperative strokes occurred in five (0.9%) patients [n = 4 (0.9%) symptomatic; n = 1 (0.7%) asymptomatic patients]. Minor stroke was recorded in six (1%) patients [n = 4 (0.9%) symptomatic; n = 2 (1.3%) asymptomatic patients]. Two patients with symptomatic stenoses died within 1 month after surgery. Nine patients (1.5%) had reversible peripheral nerve palsies, and nine patients (1.5%) suffered a perioperative myocardial infarction. High-grade (>70%) restenosis at 1 year was observed in 19 (3.2%) patients [n = 12 (2.7%) symptomatic; n = 7 (4.7%) asymptomatic patients]. Conclusions: The midterm rate of restenosis was low when using a microscope-assisted non-patch endarterectomy technique. The 30-day morbidity and mortality rate was comparable or lower than those in recently published surgical serie
Mycobacterium tuberculosis Affects Protein and Lipid Content of Circulating Exosomes in Infected Patients Depending on Tuberculosis Disease State
Tuberculosis (TB), which is caused by the bacterium Mycobacterium tuberculosis (Mtb), is
still one of the deadliest infectious diseases. Understanding how the host and pathogen interact
in active TB will have a significant impact on global TB control efforts. Exosomes are increasingly
recognized as a means of cell-to-cell contact and exchange of soluble mediators. In the case of TB,
exosomes are released from the bacillus and infected cells. In the present study, a comprehensive
lipidomics and proteomics analysis of size exclusion chromatography-isolated plasma-derived exosomes from patients with TB lymphadenitis (TBL) and treated as well as untreated pulmonary TB
(PTB) was performed to elucidate the possibility to utilize exosomes in diagnostics and knowledge
building. According to our findings, exosome-derived lipids and proteins originate from both the
host and Mtb in the plasma of active TB patients. Exosomes from all patients are mostly composed of
sphingomyelins (SM), phosphatidylcholines, phosphatidylinositols, free fatty acids, triacylglycerols
(TAG), and cholesterylesters. Relative proportions of, e.g., SMs and TAGs, vary depending on the
disease or treatment state and could be linked to Mtb pathogenesis and dormancy. We identified
three proteins of Mtb origin: DNA-directed RNA polymerase subunit beta (RpoC), Diacyglycerol
O-acyltransferase (Rv2285), and Formate hydrogenase (HycE), the latter of which was discovered to
be differently expressed in TBL patients. Furthermore, we discovered that Mtb infection alters the
host protein composition of circulating exosomes, significantly affecting a total of 37 proteins. All TB
patients had low levels of apolipoproteins, as well as the antibacterial proteins cathelicidin, Scavenger
Receptor Cysteine Rich Family Member (SSC5D), and Ficolin 3 (FCN3). When compared to healthy
controls, the protein profiles of PTB and TBL were substantially linked, with 14 proteins being coregulated. However, adhesion proteins (integrins, Intercellular adhesion molecule 2 (ICAM2), CD151,
Proteoglycan 4 (PRG4)) were shown to be more prevalent in PTB patients, while immunoglobulins,
Complement component 1r (C1R), and Glutamate receptor-interacting protein 1 (GRIP1) were found
to be more abundant in TBL patients, respectively. This study could confirm findings from previous
reports and uncover novel molecular profiles not previously in focus of TB research. However, we
applied a minimally invasive sampling and analysis of circulating exosomes in TB patients. Based on the findings given here, future studies into host–pathogen interactions could pave the way for the
development of new vaccines and therapies
Restenosis after microsurgical non-patch carotid endarterectomy in 586 patients
Carotid endarterectomy (CEA) reduces the risk of stroke in patients with symptomatic (>50%) and asymptomatic (>60%) carotid artery stenosis. Here we report the midterm results of a microsurgical non-patch technique and compare these findings to those in the literature
Prediction of Long-Term Restenosis After Carotid Endarterectomy Using Quantitative Magnetic Resonance Angiography.
Background
To detect restenosis after carotid endarterectomy (CEA), long-term monitoring is required. However, non-selective follow-up is controversial and can be limited by costs and logistical considerations.
Objective
To examine the value of immediate perioperative vessel flow measurements after CEA using quantitative magnetic resonance angiography (QMRA) to detect patients at risk of long-term restenosis.
Methods
A prospective cohort study with long-term sonographic follow-up after CEA for symptomatic internal carotid artery stenosis (ICAs) > 50%. In all patients, vessel flow has been assessed both pre- and postoperatively using QMRA within ±3 days of surgery. Data on QMRA assessment were analyzed to identify patients at risk of restenosis for up to 10 years.
Results
Restenosis was recorded in 4 of 24 patients (17%) at a median follow-up of 6.8 ± 2.6 years. None of them experienced an ischemic event. Perioperative flow differences were significantly greater in patients without long-term restenosis, both for the ipsilateral ICA (p < 0.001) and MCA (p = 0.03), compared to those with restenosis (p = 0.22 and p = 0.3, respectively). The ICA mean flow ratio (p = 0.05) tended to be more effective than the MCA ratio in predicting restenosis over the long term (p = 0.35).
Conclusion
Our preliminary findings suggest that QMRA-based mean flow increases after CEA may be predictive of restenosis over the long term. Perioperative QMRA assessment could become an operator-independent screening tool to identify a subgroup of patients at risk for restenosis, in whom long-term monitoring is advised
Spin-texture inversion in the giant Rashba semiconductor BiTeI
Semiconductors with strong spin-orbit interaction as the underlying mechanism for the generation of spin-polarized electrons are showing potential for applications in spintronic devices. Unveiling the full spin texture in momentum space for such materials and its relation to the microscopic structure of the electronic wave functions is experimentally challenging and yet essential for exploiting spin-orbit effects for spin manipulation. Here we employ a state-of-the-art photoelectron momentum microscope with a multichannel spin filter to directly image the spin texture of the layered polar semiconductor BiTeI within the full two-dimensional momentum plane. Our experimental results, supported by relativistic ab initio calculations, demonstrate that the valence and conduction band electrons in BiTeI have spin textures of opposite chirality and of pronounced orbital dependence beyond the standard Rashba model, the latter giving rise to strong optical selection-rule effects on the photoelectron spin polarization. These observations open avenues for spin-texture manipulation by atomic-layer and charge carrier control in polar semiconductors.This work was supported by DFG (through SFB 1170 'ToCoTronics') and through FOR1162 (P3). We acknowledge the support by the Basque Departamento de Educacion, UPV/EHU (Grant Number IT-756-13), Spanish Ministerio de Economia y Competitividad (MINECO Grant Number FIS2013-48286-C2-2-P), Tomsk State University Academic D.I. Mendeleev Fund Program in 2015 (Research Grant Number 8.1.05.2015), the Russian Foundation for Basic Research (Grant Numbers 15-02-01797 and 15-02-589 02717). Partial support by the Saint Petersburg State University (Grant Number 15.61.202.2015) is also acknowledged
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