On the energy-momentum tensor in non-commutative gauge theories

We study the properties of the energy-momentum tensor in non-commutative gauge theories by coupling them to a weak external gravitational field. In particular, we show that the stress tensor of such a theory coincides exactly with that derived from a theory where a Seiberg-Witten map has been implemented (namely, the procedure is commutative). Various other interesting features are also discussed.Comment: 3 page

New Polymer Syntheses Part: 55#. Novel Conducting Arylidene Polymers and Copolymers Based on Methyl-Cyclohexanone Moiety

A new interesting class of conducting polymers based on methyl-cyclohexanone in the polymer main chain has been synthesized by solution polycondensation of terephthalaldehyde with methyl-cyclohexanone. Copolymers containing different cycloalkanone moieties were also synthesized using solution polycondensation technique. The model compound I was synthesized by the interaction of methyl-cyclohexanone monomer with benzaldehyde, and its structure was confirmed by elemental and spectral analyses. The resulting new polymers and copolymers were characterized by elemental and spectral analyses, beside solubility and viscometry measurements. The thermal properties of those polymer and copolymers were evaluated by TGA, DrTGA and DTA measurements and correlated to their structural units. PDT as well as T10 was in the range from 205 to 370 ºC. In addition, T10 thermal stability for all the polymers was in theorder: VI> II > III > IV > V. X–ray analysis showed that it has some degree of crystallinity in the region 2q = 5–60 degree.The UV– visible spectra of some selected polymers were measured in DMSO solution and showed absorption bands in the range 265-397 nm, due to n – π* and π – π* transition. The morphological properties of copolymer IV as selected examples were tested by SEM. The electrical conductivities of the synthesized polymers and copolymers enhanced to become in the range of 10-9-10-8 S cm-1 by doping with iodine

INCREASED URINARY 8-OXO-7,8-DIHYDRO-2′-DEOXYGUANOSINE EXCRETION IN A SAMPLE OF EGYPTIAN CHILDREN WITH BETA THALASSEMIA MAJOR: MARKER FOR LIPID PEROXIDATION-INDUCED DNA DAMAGE

Objective: The objective of this research was to evaluate oxidative stress status in children with β-thalassemia major.Methods: Our study was conducted in children with β-thalassemia aged from 5 to 15 years. Investigate the urinary excretion of human 8-oxo-7,8- dihydro-2′-deoxyguanosine, which will be analyzed by enzyme-linked immunosorbent assay. To investigate serum levels of antioxidant enzymes include glutathione s-transferase (GST) and catalase (CAT).Results: We found a significant elevation of the urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine level with p=0.001 compared to control group, a significant reduction of both GST and CAT p=0.05 and 0.03, respectively, compared to control group. There was a significant negative correlation between urinary 8-oxo-7,8-dihydro-2′-deoxyguanisine and CAT level, r=−0.378, p=0.016, hemoglobin - r=−0.610, p=0.001, hematocrit (%) - r=−0.478, p=0.002, while a significant positive correlation between urinary 8-oxo-7,8-dihydro-2′-deoxyguanisine and alanine aminotransferase - r=0.547, p=0.001, and serum ferritin - r=0.391, p=0.013. There was a significant negative correlation between CAT and serum ferritin - r=−0.320, p=0.44.Conclusion: We conclude that the strongly increased urinary excretion 8-oxo-7,8=dihydro-2′-deoxyguanisine indicates elevated lipid peroxidation induced DNA damage in internal organs such as the liver. These highly pro mutagenic lesions may contribute to the increased risk of thalassemia patients to develop hepatocellular carcinoma

Making the hyper--K\"ahler structure of N=2 quantum string manifest

We show that the Lorentz covariant formulation of N=2 string in a curved space reveals an explicit hyper--K\"ahler structure. Apart from the metric, the superconformal currents couple to a background two--form. By superconformal symmetry the latter is constrained to be holomorphic and covariantly constant and allows one to construct three complex structures obeying a (pseudo)quaternion algebra.Comment: 8 pages, no figures, PACS: 04.60.Ds; 11.30.Pb, Keywords: N=2 string, hyper-K\"ahler geometry. Presentation improved, references added. The version to appear in PR

Momentum modes of M5-branes in a 2d space

We study M5 branes by considering the selfdual strings parallel to a plane. With the internal oscillation frozen, each selfdual string gives a 5d SYM field. All selfdual strings together give a 6d field with 5 scalars, 3 gauge degrees of freedom and 8 fermionic degrees of freedom in adjoint representation of U(N). Selfdual strings with the same orientation have the SYM-type interaction. For selfdual strings with the different orientations, which could also be taken as the unparallel momentum modes of the 6d field on that plane or the (p,q) (r,s) strings on D3 with (p,q)\neq (r,s), the [i,j]+[j,k]\rightarrow [i,k] relation is not valid, so the coupling cannot be written in terms of the standard N \times N matrix multiplication. 3-string junction, which is the bound state of the unparallel [i,j] [j,k] selfdual strings, may play a role here.Comment: 37 pages, 5 figures, to appear in JHEP; v2: reference adde

URINARY MARKERS OF OXIDATIVE DNA DAMAGE IN TYPE 1 DIABETIC CHILDREN: RELATION TO MICROVASCULAR COMPLICATIONS

  Objective: Type 1 diabetes mellitus (T1DM) is a widespread metabolic disease, which frequently carries with it a significant impact on human health. Oxidative damage and tissue inflammation have been claimed to be a typical pathogenic component for the progression of diabetic complications. We aim in this study to explore the relation of urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) (as a marker of nucleic acid oxidation) to microvascular complications in T1DM.Methods: A case–control study, enrolling 45 T1DM children and an equivalent number of healthy subjects, was performed. Full clinical examination and anthropometric measurement were performed to all subjects. Urinary assessment for 8-oxodG and albumin was done in addition to blood sampling for lipid profile and glycated Hb (HbA1c) assay. Complete ocular examination for assessment of diabetic retinopathy (DR) was also done.Results: Levels of urinary 8-oxodG, serum cholesterol, triglycerides, and low-density lipoprotein in cases were significantly higher than non-diabetics; these levels were likewise higher in uncontrolled T1DM patients in comparison with well-controlled T1DM subjects. Urinary 8-oxodG and HbA1c were significantly higher in diabetic patients with albuminuria and DR compared to patients without complications. Significant positive correlation was found between 8-oxodG with HbA1c (r=0.8, p<0.01), diastolic blood pressure (DBP) (r=0.4, p=0.02), and cholesterol (r=0.4, p=0.05).Conclusion: Urinary 8-oxodG was found to be a reliable marker for assessing oxidative DNA damage in T1DM and can be used in the determination of microvascular complications related to diabetes

The use of HPV-DNA testing combined with Pap smear in detection of pre-invasive disease of the cervix

Background: Cancer cervix constitutes a major health problem worldwide. It is one of the most common female malignancy in both incidence and mortality. Cancer cervix has many risk factors, the most important one is persistent infection with one of HPV high risk types. Its morbidity and mortality can be reduced by frequent screening and early diagnosis. So that, several studies have been conducted in recent years in order to find better tests for screening for pre-invasive disease of the cervix and so early intervention and better prognosis. This study aimed to compare the sensitivity of Pap test and HPV DNA test as screening tests for pre-invasive disease of the cervix.Methods: 100 females from those attending Alexandria University gynaecologic clinic for causes rather than cancer cervix were subjected to Pap smear and cervical swab for HPV-DNA testing at the same setting. Cases of HSIL or positive HPV were subjected to VIA test, colposcopy and cervical punch biopsy was taken if aceto-whitening of the cervix or any other abnormality was found. Cases with ASCUS or LSIL were re-smeared after 3-6 months, if persistent or progressive pathology, colposcopy and punch biopsy from acetowhite areas were taken.Results: 21 cases (21%) were HPV positive and 66 cases (66%) were positive for intraepithelial lesions (37% ASCUS, 18% LSIL and 11% HSIL) with re-smearing there were 3 persistent ASCUS cases (8.1%) and 5 LSIL cases (27.78%). Colposcopy done, and biopsies were taken from 10 HSIL cases (90.1%), 5 LSIL (27.8%), 3 ASCUS (8.1%) and 10 HPV positive cases (62.5%). With significant relationship between colposcopic findings and HPV-DNA positivity and abnormal cytology. Biopsies were 18; 14 were CIN I and 4 were CIN II.Conclusions: HPV-DNA positivity has positive association with HSIL. Pap smear is an easy cheap method for screening. HPV-DNA test is less sensitive than cytology as a method for screening

D-brane orbiting NS5-branes

We study real time dynamics of a Dp-brane orbiting a stack of NS5-branes. It is generally known that a BPS D-brane moving in the vicinity of NS5-branes becomes unstable due to the presence of tachyonic degree of freedom induced on the D-brane. Indeed, the D-brane necessarily falls into the fivebranes due to gravitational attraction and eventually collapses into a pressureless fluid. Such a decay of the D-brane is known to be closely related to the rolling tachyon problem. In this paper we show that in special cases the decay of D-brane caused by gravitational attraction can be avoided. Namely for certain values of energy and angular momentum the D-brane orbits around the fivebranes, maintaining certain distance from the fivebranes all the time, and the process of tachyon condensation is suppressed. We show that the tachyonic degree of freedom induced on such a D-brane really disappears and the brane returns to a stable D-brane.Comment: 12 pages, latex, added referenc

String Multiplets from an Invariant 2-Brane

We study a three-dimensional gauge theory obtained from the dimensional reduction of a D4-brane worldvolume theory in the background of space-time moduli. An SL(3) symmetry in this theory, which acts on fields as well as coupling constants, is identified. By comparing the energies with the string tensions, we show that certain 1/2 supersymmetric classical solutions of this theory can be identified as SL(3,Z) multiplets of type II strings in eight dimensions. Results are then generalized to the non-linear Born-Infeld action. We also discuss the possibility of 1/8 BPS states in this theory and their representations in terms of string networks.Comment: 17 pages, Latex, minor correction

Superbrane Actions and Geometrical Approach

We review a generic structure of conventional (Nambu-Goto and Dirac-Born-Infeld-like) worldvolume actions for the superbranes and show how it is connected through a generalized action construction with a doubly supersymmetric geometrical approach to the description of super-p-brane dynamics as embedding world supersurfaces into target superspaces.Comment: Based on talks given by the authors at the Volkov Memorial Seminar "Supersymmetry and Quantum field Theory" (Kharkov, January 5-7, 1997), LaTeX file, 11 pages Misprints corrected, references adde