939 research outputs found
Probabilistic coding of quantum states
We discuss properties of probabilistic coding of two qubits to one qutrit and
generalize the scheme to higher dimensions. We show that the protocol
preservers entanglement between qubits to be encoded and environment and can be
also applied to mixed states. We present the protocol which enables encoding of
n qudits to one qudit of dimension smaller than the Hilbert space of the
original system and then probabilistically but error-free decode any subset of
k qudits. We give a formula for the probability of successful decoding
Towards symmetric scheme for superdense coding between multiparties
Recently Liu, Long, Tong and Li [Phys. Rev. A 65, 022304 (2002)] have
proposed a scheme for superdense coding between multiparties. This scheme seems
to be highly asymmetric in the sense that only one sender effectively exploits
entanglement. We show that this scheme can be modified in order to allow more
senders to benefit of the entanglement enhanced information transmission.Comment: 6 page
Variations in popliteal fossa venous anatomy: implications for diagnosis of deep-vein thrombosis
Background: To retrospectively review the bilateral venous system within the popliteal fossa to evaluate the types of variations and their frequency seen in venous anatomy.Materials and methods: During routine dissection of formalin-fixed cadavers, a retrospective review of 32 bilateral (64 limbs) lower limbs obtained from adult donors was performed. Deep veins present in the popliteal fossa were evaluated according to predetermined criteria for the presence of duplication of vessels and interindividual variations in venous anatomy.Results: More than one deep venous vessel was seen in the popliteal fossa in 20 (31.3%) of 64 limbs. In 12 (18.7%) cases there was a high (just below the level of the adductor hiatus) origin of the popliteal vein: from 2 tributaries in 10 (15.6%) and 3 tributaries in 2 (3.1%). In 5 (7.8%) cases true duplicated popliteal veins were observed. There were also 3 (4.7%) cases, including one bilateral, of persistent sciatic vein.Conclusions: Variations in popliteal fossa venous anatomy are common and have important implications for the diagnosis of deep vein thrombosis
Myostatin and its precursor protein are increased in the skeletal muscle of patients with Type-II muscle fibre atrophy
Preferential atrophy of Type-II muscle fibres occurs in several clinical situations,
including cachexia, muscle disuse, chronic glucocorticoid treatment, remote
neoplasia, and sometimes as an aspect of recent-denervation. For the patient,
the Type-II atrophy itself might be unfavourable (as a glucocorticoid side-effect) or favourable (survivalistic via the muscle-alanine liver-gluconeogenesis
pathway in starvation). The cellular mechanisms underlying Type-II fibre atrophy
are unclear. Myostatin (Mstn) is physiologically a negative regulator of
muscle mass and strength. In this study we evaluated a possible role of Mstn in
Type-II fibre atrophy in human muscle. Mstn and Mstn precursor protein
(MstnPP) were studied in 10-muscle biopsies containing Type-II fibre atrophy
and in 17 disease and normal control muscle biopsies. When comparison was
made with normal control fibres, we found the following: 1) by immunocytochemistry,
diffusely increased Mstn/MstnPP in the atrophic Type-II muscle
fibres; 2) by immunoblots, Mstn/MstnPP increased individually; 3) by RT-PCR,
no increase in MstnPP mRNA. In conclusion, our results a) suggest that Mstn/
/MstnPP might play a role in the pathogenic cascade of Type-II muscle fibre
atrophy; b) broaden our previously-described associations of Mstn in human
muscle pathology, and c) could possibly lead to clinical prevention when Type-II
muscle fibre atrophy is unfavourable, for instance in glucocorticoid therapy.
(Folia Morphol 2008; 67: 1-7
Vibration Analysis of Collecting Electrodes by means of the Hybrid Finite Element Method
The paper presents a hybrid finite element method of shell modeling in order to model collecting electrodes of electrostatic precipitators. The method uses the finite element method to reflect elastic features and the rigid finite element method in order to model mass features of the body. A model of dust removal systems of an electrostatic precipitator is presented. The system consists of two beams which are modeled by means of the rigid finite element method and a system of collecting shells modeled by means of the hybrid finite element method. The paper discusses both the procedure of deriving the equations of motion and the results of numerical simulations carried out in order to analyze vibrations of the whole system. Experimental verification of the model is also presented
Reduced level of synapsin I protein in the rat striatum after intraventricular administration of proteasome inhibitors: preliminary studies
Background: We have recently described changes present in nigrostriatal terminals after intraperitoneal administration of MG-132 and changes that occur in the walls of the rat lateral ventricle after intraventricular administration of MG-132, lactacystin and epoxomicin — different classes of proteasome inhibitors. Substances that inhibit ubiquitin-proteasome system (UPS) activity, are intensively studied due to their potential role as novel therapeutic strategies in the treatment of cancer and ischaemia-reperfusion injury in the brain. The aim of this study is to determine the influence of intraventricular administration of MG-132, lactacystin and epoxomicin on the level in the rat striatum synapsin I — one of the most prominent neuron-specific phosphoproteins in the brain.
Materials and methods and Results: Two weeks after administration of studied proteasome inhibitors, substantial reduction (up to 80%) of synapsin I was observed in the rat striatum. Because neurons, and especially dopaminergic ones, are sensitive to the depletion of proteasome function, we assume that observed synapsin I decrease may reflect changes in population of striatal neurons and/or nigrostriatal terminals.
Conclusions: Understanding of cellular mechanisms standing behind our findings needs further studies, and could provide valuable contribution to the discussion on the mechanisms linking UPS inhibition and survival of neurons.
A case of multiple abnormalities of the azygos venous system: a praeaortic interazygos vein
The posterior thoracic wall, an area drained by the azygos venous system, is
a common site for surgical intervention. Since the venous part of the cardiovascular
system is subject to most common variation, abnormalities in the azygos
venous system are often reported. Some of the anatomical variants have significant
clinical implications for computed tomography image assessment and
mediastinal surgery.
During dissection of the posterior mediastinum in a 76 year-old Caucasian male
cadaver we found a rare variation in the azygos venous system. The hemiazygos
vein drained the left 9th to 11th left posterior intercostal veins. While passing ventrally
to the aorta at the level of the body of the eighth thoracic vertebra it was
joined by two separate vessels found to be the continuations of the 7th and 8th left
posterior intercostal veins. The resultant dilated vessel, termed the "interazygos
vein", then opened into the azygos vein on the right side of the vertebral column.
Variation in the azygos venous system has often been reported, but the abnormality
observed by us appears to be extremely rare. The interazygos vein passing
ventrally to the aorta may mimic enlarged lymph nodes and cause misinterpretation
of a computed tomography image or, if accidentally damaged during mediastinal
surgery, may lead to intraoperative haemorrhage. To the best of our knowledge
this report provides new data of potential clinical significance
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Public health for the people: participatory infectious disease surveillance in the digital age
The 21st century has seen the rise of Internet-based participatory surveillance systems for infectious diseases. These systems capture voluntarily submitted symptom data from the general public and can aggregate and communicate that data in near real-time. We reviewed participatory surveillance systems currently running in 13 different countries. These systems have a growing evidence base showing a high degree of accuracy and increased sensitivity and timeliness relative to traditional healthcare-based systems. They have also proven useful for assessing risk factors, vaccine effectiveness, and patterns of healthcare utilization while being less expensive, more flexible, and more scalable than traditional systems. Nonetheless, they present important challenges including biases associated with the population that chooses to participate, difficulty in adjusting for confounders, and limited specificity because of reliance only on syndromic definitions of disease limits. Overall, participatory disease surveillance data provides unique disease information that is not available through traditional surveillance sources
Distribution of neuronal nitric oxide synthase (nNOS)-immunoreactive elements in the rabbit piriform cortex
The piriform cortex (PC), the primary olfactory cortex, is involved in the processes
of learning and stress response and possibly plays an important role in epileptogenic
activity. The results of several recent studies suggest that those PC neurons
that contain neuronal nitric oxide synthase (nNOS) may play a key role
during spatial learning and in the modulation of initiation, propagation and
generalisation of seizures in various experimental models and may influence
neuronal vulnerability after epileptic insults. The aim of this study was to characterise
the pattern of distribution and morphology of nNOS-immunoreactive elements
in PC of the adult rabbit. The co-localisation of nNOS and calretinin (CR)
was also studied. The pattern of nNOS-ir within the rabbit PC is similar to that
described previously in other mammals. The morphology of nNOS-ir elements,
namely varicose fibres and Cajal-Retzius cells, suggest that NO has an important
influence on PC function. Surprisingly, in the rabbit PC nNOS-ir elements show
a very low level of co-localisation with CR-ir
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