Fermions from photons: Bosonization of QED in 2+1 dimensions

We perform the complete bosonization of 2+1 dimensional QED with one fermionic flavor in the Hamiltonian formalism. The Fermi operators are explicitly constructed in terms of the vector potential and the electric field. We carefully specify the regularization procedure involved in the definition of these operators, and calculate the fermionic bilinears and the energy - momentum tensor. The algebra of bilinears exhibits the Schwinger terms which also appear in perturbation theory. The bosonic Hamiltonian is a local, polynomial functional of $A_i$ and $E_i$, and we check explicitly the Lorentz invariance of the resulting bosonic theory. Our construction is conceptually very similar to Mandelstam's construction in 1+1 dimensions, and is dissimilar from the recent bosonization attempts in 2+1 dimensions, which hinge crucially on the presence of a Chern - Simons term.Comment: 30 pages, LA - UR - 93 - 200

A Candidate for Exact Continuum Dual Theory for Scalar QED3_3

We discuss a possible exact equivalence of the Abelian Higgs model and a scalar theory of a magnetic vortex field in 2+1 dimensions. The vortex model has a current - current interaction and can be viewed as a strong coupling limit of a massive vector theory. The fixed point structure of the theory is discussed and mapped into fixed points of the Higgs model.Comment: 17 pages, 1 figure available on request, LA-UR-93-83

Vortex condensation in a model of random ϕ4\phi^{4}-graphs

We consider a soluble model of large $\phi^{4}$-graphs randomly embedded in one compactified dimension; namely the large-order behaviour of finite-temperature perturbation theory for the partition function of the anharmonic oscillator. We solve the model using semi-classical methods and demonstrate the existence of a critical temperature at which the system undergoes a second-order phase transition from $D=1$ to $D=0$ behaviour. Non-trivial windings of the closed loops in a graph around the compactified time direction are interpreted as vortices. The critical point has a natural interpretation as the temperature at which these vortices condense and disorder the system. We show that the vortex density increases rapidly in the critical region indicating the breakdown of the dilute vortex gas approximation at this point. We discuss the relation of this phenomenon to the Berezinskii-Kosterlitz-Thouless transition in the $D=1$ matrix model formulated on a circle.Comment: 12 pages, LaTeX, (5 figures not included

The rtPA increases MMP-9 activity in serum during ischaemic stroke

Background and purpose To find the relationship between rtPA treatment vs. MMP-9 activity, MMP-3, and TIMP-1 serum levels related to patients’ neurological status during acute ischaemic stroke (IS). Material and methods 35 IS patients were enrolled. 14 of them underwent thrombolytic therapy with Actylise (rtPA group). The serum samples were obtained at 3 time-points for rtPA group (time-point 0: 1st–4th hour of stroke; time-point 1 – immediately after rtPA administration; time-point 2 – on day 5–7 from stroke onset). Remaining patients had venous blood collection at two time-points: time-point 1 – 5th–10th hour of stroke and time-point 2 – on day 5–7 of stroke. MMP-9 was analyzed with gelatin zymography, MMP-3 and TIMP-1 serum levels were analyzed with ELISA method. NIHSS improvement ratio (IR) was calculated as a difference between NIHSS score at the admission and discharge of patient. Results The active form of MMP-9 (86kDa) was not observed in any analyzed samples. Total MMP-9 activity was significantly elevated at time-point 1 in rtPA group in comparison with non-rtPA group. MMP-3 serum level significantly decreased during rtPA administration in comparison with non-rtPA group and it was restored at time-point 2. MMP-3 negatively correlated with IR values (p=0.06). Conclusions Thrombolysis applied for IS treatment increases MMP-9 activity in serum, however, rtPA does not facilitate the conversion of pro-MMP-9 into the active form. Our results also suggest the involvement of MMP-3 to the biochemical processes occurring during acute phase of IS

Fermionic Operators from Bosonic Fields in 3+1 Dimensions

We present a construction of fermionic operators in 3+1 dimensions in terms of bosonic fields in the framework of $QED_4$. The basic bosonic variables are the electric fields $E_i$ and their conjugate momenta $A_i$. Our construction generalizes the analogous constuction of fermionic operators in 2+1 dimensions. Loosely speaking, a fermionic operator is represented as a product of an operator that creates a pointlike charge and an operator that creates an infinitesimal t'Hooft loop of half integer strength. We also show how the axial $U(1)$ transformations are realized in this construction.Comment: 8 pages, two figures available on request, LA-UR-94-286

Bosonization in 2+1 dimensions without Chern - Simons attached

We perform the complete bosonization of 2+1 dimensional QED with one fermionic flavor in the Hamiltonian formalism. The fermion operators are explicitly constructed in terms of the vector potential and the electric field. We carefully specify the regularization procedure involved in the definition of these operators, and calculate the fermionic bilinears and the energy - momentum tensor. The algebra of bilinears exhibits the Schwinger terms which also appear in perturbation theory. The bosonic Hamiltonian density is a local polynomial function of $A_i$ and $E_i$, and we check explicitly the Lorentz invariance of the resulting bosonic theory. Our construction is conceptually very similar to Mandelstam's construction in 1+1 dimensions, and is dissimilar from the recent bosonization attempts in 2+1 dimensions which hinge crucially on the existence of a Chern - Simons term.Comment: 12 pages, LA-UR-93-1062, some misprints and algebraic errors corrected, several comments adde

The importance of CAD and DECT in CT colonography

IntroductionAccording to the American College of Radiology and the American Cancer Society, CTC has been recognized as a valuable screening method for detecting CRC in people at medium risk as an alternative to endoscopic colonoscopy. The condition for the proper interpretation of this procedure is the patient’s preparation for the examination. The evaluation of the test includes: topogram, transverse images (as reference images), multifaceted reconstructions and three-dimensional images (3D navigator). Materials and methods                            The literature on the use of CTC in the diagnosis of CRC was analyzed. A review of the scientific literature indexed in the PUBMED database from the last 10 years was carried out. Results The introduction of dual energy computed tomography (DECT) clearly improved the diagnostic accuracy of CTC. The main advantage of DECT is the possibility of obtaining iodine maps and VNC (virtual non-contrast) – a ’’virtual’’ native image (without the use of contrast). DECT allows you to monitor the results and extent of iodine capture on VNC and iodine map images, respectively, without using pre-recorded tomographic images. Pilot tests showed that DECT is an effective tool in CT colonography diagnostics and electronic colon loop cleaning after barium labeling. The use of the Computer Aided Diagnosis (CAD) algorithm in high energy tomography helps in the diagnosis and detection of intestinal tumors. ConclusionsThe development of modern technologies used in CT colonography proves that it is a safe and acceptable technique for patients. Lack of invasiveness, low radiation dose and high diagnostic efficiency of CTC may encourage more people to undergo colorectal cancer screening in the future

Osteoarthritis of the knee - biochemical aspect of applied therapies: a review

The most prevalent form of arthritis is osteoarthritis (OA) of the knee, which is characterized by a degeneration of articular cartilage resulting in the development of osteophytes, or bone spurs. Main goals of OA treatment are to reduce pain, slow the disease progression, and improve joint function and the quality of life. The purpose of this study was to verify all the therapies recommended by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) from the biochemical point of view. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the synthesis of eicosanoids, whereas paracetamol prevents the production of prostaglandin (PG) by interacting with peroxidase (POX) site of the prostaglandin H2 synthase complex. Tramadol is an opioid that has a dual mechanism of action: it binds to the μ-opioid receptor and it inhibits serotonin and adrenaline. Corticosteroids, which are also prescribed for OA pain, inhibit the activity of phospholipase A2 and block the synthesis of arachidonate-derived eicosanoids. Symptomatic slow-acting drugs for osteoarthritis (SYSADOA) are drugs that are well tolerated by patients and help to restore proteoglycan matrix of the cartilage. These drugs include compounds that naturally build articular cartilage. The articular cartilage, as well as the bone located around the cartilage, are destroyed as osteoarthritis progresses. Thus, bisphosphonates, commonly used in the treatment of osteoporosis, were evaluated as potential therapy. However, there is no official recommendation for their use in therapy. The aim of the study was to analyze the biochemical mechanisms of principal drugs used for the treatment of knee OA. Therefore, a narrative review summarizing the current knowledge regarding the applied therapies was prepared

Persistent trigeminal artery as a rare cause of ischaemic lesion and migraine-like headache

The persistent trigeminal artery (PTA) is a rare remnant of the embryonic intracranial circulatory system that forms a carotid-vertebrobasilar anastomosis. In most cases PTA does not have clear clinical implications. However, some authors report the association of PTA occurrence with vertigo, dizziness and nerve palsy, resulting in diplopia, strabismus or trigeminal neuralgia in patients. In rare cases it may also be related to posterior cerebral circulation strokes. This work reports the case of a female patient who presented with migraine-like headache and an ischaemic lesion in the left temporal lobe in association with PTA

Coronary artery fistulas morphology in coronary computed tomography angiography

Background: The aim of the study was to evaluate coronary artery fistulas (CAFs) in coronary computed tomography angiography (coronary CTA) and verify whether there is correlation between the fistula’s morphology and other cardiac functional findings and clinical data.Materials and methods: A group of 14,308 patients who were diagnosed in coronary CTA was retrospectively analysed. Achieved data were related to referrals.Results: Coronary artery fistula frequency was 0.43% in the examined population. The assessment of coronary artery disease was the most frequent indication for the examination. In 2 out of 3 cases the diagnosis of CAFs was incidental. Fistulas to cardiac chambers were significantly shorter than those to other vascular structures (19.9 vs. 61.8 mm, respectively, p = 0.001). Pulmonary trunk was most often the drainage site. Fistulas with singular supply and drainage constituted the majority. The new morphologic classification of CAFs was introduced with linear, spiral, aneurysmal, grid-like and mixed types. Most numerous was the spiral type group. Patients with aneurysmal fistulas had a tendency for wider diameter of aorta and pulmonary trunk. Smallest left ventricle fraction was observed in gridlike fistulas (48.0%, comparing to 59.2% for all patients with fistulas, p = 0.001). Concomitant abnormalities were found in 13.1% of CAFs patients.Conclusions: Computed tomography angiography has proven to be a useful tool in CAFs detection and morphological assessment. Proposed classification may simplify the predictions whether fistula has a significant influence on cardiac function; however, further studies are needed