323,791 research outputs found
Novel modulators of non-selective and selective autophagy
No full textPå samme måte som søppel dannes fra vårt daglige forbruk, produserer cellene i kroppen vår avfallsprodukter som transporteres til cellens resykleringsstasjon (lysosomet), hvor det brytes ned og gjenvinnes. Dette skjer via en prosess kalt autofagi, som involverer oppsamling av kargo/søppel i en vesikkel (et autofagosom) som smelter sammen med lysosomet. Autofagi oppreguleres ved stress, f.eks sult, men et basalt nivå av autofagi er viktig i alle celler for å beskytte mot sykdommer som kreft og nevrodegenerering.
Dannelsen av autofagosomer er vist å involvere en rekke proteinkomplekser og lipider, men de eksakte mekanismene involvert i regulering av autofagi er ikke kjent. I denne avhandlingen har Benan John Mathai og medarbeidere vist at proteinet HS1BP3 er en negativ regulator av autofagi. De fant at HS1BP3 inhiberer autofagi ved å hemme aktiviteten til det lipid-modifiserende enzymet PLD1, som igjen er viktig for å lage lipidet fosfatidsyre (PA) som er vist å være viktig for autofagi. Mathai fant at den regulatoriske rollen til HS1BP3 i autofagi er konservert i zebrafisk larver som uttrykker en fluoreserende markør for autofagi (LC3).
Selektiv nedbryting av spesialavfall (som dysfunksjonelle mitokondrier eller protein aggregater) ved autofagi krever spesielle autofagi-reseptorer (f.eks p62) som binder kargo. Benan John Mathai og medarbeidere har identifisert et «eat-me signal» på mitokondrier som gjenkjennes av slike autofagi reseptorer. Ved depolarisering av mitokondriene akkumulerer matriksproteinene NIPSNAP1 og NIPSNAP2 på overflaten av mitokondriene hvor de binder autofagireseptorer, som fører til nedbrytning av de ødelagte mitokondriene (mitofagi). NIPSNAP1/2-mediert mitofagi er avhengig av proteinene PINK1 og PARKIN, som begge er assosiert med Parkinsons sykdom. Mathai fant at zebrafisk larver som mangler Nipsnap1 har økt oksidativt stress, redusert nivå av dopaminerge nevroner og redusert bevegelse.
Dette doktorgradsarbeidet er et viktig bidrag til vår forståelse av de molekylære mekanismene involvert i regulering og dannelse av autofagosomer og gir innsikt i betydningen av disse prosessene i å hindre utvikling av sykdom
Higher abelian gauge theory associated to gerbes on noncommutative deformed M5-branes and S-duality
No full textAbstract not availableVarghese Mathai, Hisham Sat
On the Mathai-Quillen formalism of topological sigma models
No full textWe present a Mathai-Quillen interpretation of topological sigma models. The key to the construction is a natural connection in a suitable infinite-dimensional vector bundle over the space of maps from a Riemann surface (the world sheet) to an almost complex manifold (the target). We show that the covariant derivative of the section defined by the differential that appears in the equation for pseudo-holomorphic curves is precisely the linearization of the operator itself. We also discuss the Mathai-Quillen formalism of gauged topological sigma models. © 1995.postprin
Stenaelurillus metallicus Caleb & Mathai, 2016, sp. nov.
No full text<i>Stenaelurillus metallicus</i> sp. nov. <p>Figs 1–22</p> <p> <b>Type material: Holotype:</b> Male (NCBS-AR103) from Madras Christian College (12.917659°N, 80.122859°E, alt. 32 m), Chennai, Tamil Nadu, India, 21 June 2013, leg. John Caleb T.D. <b>Paratypes</b> (from same location): 1 male (NCBS- AR110), 21 June 2013; 1 male (NCBS-AR109), 18 July 2013; 1 male & 1 female (NCBS-AR104 & AR113), 5 September 2013; 1 female (NCBS-AR112), 11 November 2013; 1 male (NCBS-AR111), 21 April 2015, all leg. John Caleb T.D.; 4 males & 4 females (NCBS-AR105 to AR108 & AR114 to AR117), 30 January 2014, leg. Karthy.</p> <p> <b>Etymology.</b> The specific name, an adjective, refers to the shining spots with metallic sheen on the male abdomen.</p> <p> <b>Diagnosis.</b> The male differs from all known <i>Stenaelurillus</i> species by orangish abdomen, with a pair of dark spots (Fig. 1; usually darker abdomen with white spots in other species). The species seems to be closely related to <i>S. sarojinae</i> Caleb & Mathai, 2014 by the presence of a well-developed ventral femoral distal process in the male palp (Fig. 11), but differs in having a slightly bent, short and thick embolus, not accompanied by a terminal apophysis (compare Fig. 19 herein with fig. 80 in Caleb <i>et al.</i> 2015). The female resembles <i>S. sarojinae</i> in having a pair of white spots on the abdomen, but differs in having globular spermatheca (bean-shaped in <i>S. sarojinae</i>; compare Figs 18, 22 herein with fig. 30 in Caleb & Mathai 2014).</p> <p> <b>Description. Male</b> (holotype). Total length: 4.63; carapace: 2.37 long, 1.64 wide; abdomen: 2.26 long, 1.43 wide. Carapace dark, covered with reddish-brown hairs; a pair of thin longitudinal white stripes extending from behind the ALEs and ending at posterior slope. Posterior end of carapace blackish (Figs 1–2). AMEs surrounded by white orbital setae. Short white hairs clothe the facial region from above the anterior eyes to the clypeal region (Fig. 3). Broad patch of white hairs extend backwards on the lateral margins of the carapace. Outer edge of carapace lined by thin stripe of white hairs. Eye measurements: AME 0.36, ALE 0.21, PME 0.07, PLE 0.26, AME–AME 0.09; AME–ALE 0.12; PME–PME 1.22; PME–PLE 0.19. Sternum oval, darkly pigmented medially, yellowish along the margins (Fig. 8). Chelicerae unident (Fig. 9); labium and maxillae yellowish. Femur I with a black patch prolaterally (Fig. 3). Coxae of all legs with patch of dark pigmentation ventrally (Fig. 8). Leg measurements: I 3.99 (1.35, 0.82, 0.74, 0.58, 0.49); II 3.95 (1.37, 0.79, 0.72, 0.56, 0.51); III 5.87 (1.78, 0.84, 1.14, 1.32, 0.79); IV 5.71 (1.70, 0.80, 1.11, 1.32, 0.78). Leg spination: leg I: Fm d 0-1-1-5; Pt pr 0-1-0; Tb pr 1-1, v 1-1 -2ap; Mt pr 1-1, v 2-2 ap; leg II: Fm d 0-1-1-5, pr 0-1-0; Pt pr and rt 0-1-0; Tb pr 1- 1-1, rt 0-1-0, v 1-1 -2ap; Mt pr 1-1, rt 1-1, v 2 -0-2ap; leg III: Fm d 0-1-1-5, pr 0-1-0; Pt pr and rt 0-1-0; Tb d 1-2-2, pr 1- 1, rt 1-0-1, v 0-1-2ap; Mt d 1-2-1-2, pr 1-1, rt 1-1-1, v 0-0-2ap; leg IV: Fm d 0-1-1-4, pr 0-1-0; Pt pr and rt 0-1-0; Tb d 1- 2-2, pr 1-1, rt 1-1, v 1-2 ap; Mt d 2-2-2, pr 1-1, rt 1-0-1, v 0-1-2ap. Abdomen with dark orange hairs on the sides, paler mid-dorsally with whitish hairs making indistinct chevron shaped markings; a pair of large spots with metallic luster present on the dorsum; a pair of indistinct black spots present laterally further behind. Abdomen outlined laterally by a fringe of long white hairs; spinnerets moderately long, black (Figs 1, 7, 10). Palp covered with short pale yellowish hairs; embolus short, thick and slightly bent, not accompanied by anterior terminal apophysis; RTA single with a broad base tapering toward the tip, slightly curved (Figs 19–20).</p> <p> <b>Female</b> (paratype NCBS-AR112). Total length 4.85; carapace: 2.15 long, 1.68 wide; abdomen: 2.70 long, 2.01 wide. Eye measurements: AME 0.39, ALE 0.20, PME 0.07, PLE 0.22, AME–AME 0.06; AME–ALE 0.10; PME–PME 1.25; PME–PLE 0.19. Leg measurements: I 3.58 (1.30, 0.60, 0.61, 0.48, 0.59); II 3.65 (1.29, 0.65, 0.60, 0.54, 0.58); III 6.19 (1.97, 0.94, 1.29, 1.18, 0.81); IV 5.65 (1.67, 0.80, 1.17, 1.24, 0.77). Leg spination: leg I: Fm d 0-1-1-5; Pt pr 0-1-0; Tb pr 1-1, v 1-1 -2ap; Mt pr 0-2, v 2-1 ap; leg II: Fm d 0-1-1-5, pr 0-1-0; Pt pr 0-1-0; Tb, pr 1-1, v 1-1 -2; Mt d 1-2, pr 0-1, v 2- 1 ap; leg III: Fm d 0-1-1-5, pr 0-1-0; Pt pr and rt 0-1-0; Tb d 1-2-2, pr 1-1, rt 1-1, v 0-1-2ap; Mt d 1-1-2, pr 1-2, rt 1-1-2ap, v 0-1-2ap; leg IV: Fm d 0-1-1-4; Pt pr and rt 0-1-0; Tb d 1-2-2, pr 1-1, rt 1-1, v 1-2 ap; Mt d 2-1-2, pr 1-1, rt 1-1, v 0-1- 2ap. Coloration pattern as in male, but differs in the following: general body color dull reddish-brown (Figs 4, 12).</p> <p>Anterior eyes outlined by reddish-brown setae on the upper half and lower half with white orbital setae (Fig. 6). A pair of white spots present on the abdomen (Figs 4, 12). Epigyne placed on a poorly sclerotized plate; copulatory ducts short, leading to the lower chambers (Figs 15, 16, 21); spermathecae globular (Figs 17, 18, 22).</p> <p> <b>Distribution.</b> Known only from type locality.</p>Published as part of <i>Caleb, John T. D. & Mathai, Manu Thomas, 2016, A new jumping spider of the genus Stenaelurillus Simon, 1886 from India (Araneae: Salticidae: Aelurillina), pp. 185-188 in Zootaxa 4103 (2)</i> on pages 185-188, DOI: <a href="http://zenodo.org/record/256878">10.5281/zenodo.256878</a>
Letter of condolence to P.R.S. Mani’s sister, Girija Karthikeyan, from Ranjan Mathai, Indian Foreign Secretary, 2011
No full textLetter of condolence to Smt. Girija Karthikeyan (sister of P.R.S. Mani), from Ranjan Mathai, on behalf of the Indian Foreign Service regarding Mani’s passing, dated 3 September 2011
Genital and urinary tract infections in pregnancy in southern India : diagnosis, management and impact om perinatal outcome
No full textBackground: Prevalence of sexually transmitted infections varies in different parts of the world. These infections, occurring during pregnancy, can result in adverse outcome. There is paucity of information on the prevalence, effects and management of such infections in pregnancy in India. Similarly, urinary tract infection (UTI) is a common medical problem in pregnancy. But, very little is known about the patterns and mechanism of antimicrobial resistance among bacteria causing UTI and the prescription practices for this condition. Diagnostic methods, used for early onset sepsis (EOS) in the new-born also need evaluation.Methods: Endocervical samples from consecutive pregnant women at 26 to 36 weeks of gestation were tested to detect infection with Chlamydia trachomatis. Association of this infection with adverse pregnancy outcome was determined In another retrospective cohort study, information related to pregnancy and outcome was collected from pregnant women with reactive Venereal Disease Research Laboratory (VDRL) test, which was done as part of antenatal care. Data on susceptibility patterns of bacteria isolated in significant counts from urine of pregnant women suspected to have urinary infection were collected. To understand the mechanism of resistance, the prevalence of integrons among these E. coli were determined Prescribing patterns for these infections were ascertained using a questionnaire and based on antibiotics dispensed to pregnant women. To evaluate the use of CRP in diagnosing EOS, CRP levels in cord blood and neonatal blood at 24 hrs were estimated in two groups of neonates, one at risk of developing infection and the other at low risk of infection.Results: Prevalence of C trachomatis infection was 3.3% and this infection did not contribute significantly to adverse pregnancy outcome. Prevalence of syphilis was also low. However, fetal loss occurred in 32% of the infected women. The difference in outcome between those receiving antenatal care and those without was significant (P = 0.01; RR 7.53 95% Cl 1.1 - 51.9). In 2002, > 90% of E. coli causing UTI was susceptible to nitrofurantoin, a relatively inexpensive and safe drug. However, less than 25% of doctors used it for treatment of cystitis. The choice and duration of therapy varied greatly.Resistance to ampicillin (pDiscussion: The prevalence of STIs among antenatal women is low. However, syphilis is an unrecognised cause of pregnancy loss in the area. There are several lacunae in the diagnosis and treatment of infections in pregnancy - both UTI and STIs. A major reason probably is the lack of locally relevant uniform guidelines for the diagnosis and management of these conditions. There is also complacency because of low prevalence of STIs in pregnancy. We also observed that auditing the management of syphilis in pregnancy could be an effective and simple tool to assess the quality of antenatal care. High prevalence of resistance among E coli is associated with integrons. Since CRP levels rise in babies without infection, this test may be useful only in excluding infection.List of scientific papersI. Alexander R, Mathai E, Nayyar V, Mathew M, Jasper P (1993). "Low prevalence of chlamydial endocervical infection in antenatal south Indian women." Genitourin Med 69(3): 240-1 https://pubmed.ncbi.nlm.nih.gov/8335319II. Mathai E, Mathai M, Prakash JA, Bergstrom S (2001). "Audit of management of pregnant women with positive VDRL tests." Natl Med J India 14(4): 202-4 https://pubmed.ncbi.nlm.nih.gov/11547524III. Mathai E, Thomas RJ, Chandy S, Mathai M, Bergstrom S (2004). "Antimicrobials for the treatment of urinary tract infection in pregnancy: practices in southern India. " Pharmacoepidemiol Drug Saf 13(9): 645-52 https://pubmed.ncbi.nlm.nih.gov/15362088IV. Mathai E, Grape M, Kronvall G (2004). "Integrons and multidrug resistance among Escherichia coli causing community-acquired urinary tract infection in southern India. " APMIS 112(3): 159-64 https://pubmed.ncbi.nlm.nih.gov/15153157V. Mathai E, Christopher U, Mathai M, Jana AK, Rose D, Bergstrom S (2004). "Is C-reactive protein level useful in differentiating infected from uninfected neonates among those at risk of infection? " Indian Pediatr 41(9): 895-900 https://pubmed.ncbi.nlm.nih.gov/15475630</p
D-branes, RR-fields and duality on noncommutative manifolds
No full textWe develop some of the ingredients needed for string theory on noncommutative spacetimes, proposing an axiomatic formulation of T-duality as well as establishing a very general formula for D-brane charges. This formula is closely related to a noncom4 mutative Grothendieck-Riemann-Roch theorem that is proved here. Our approach relies on a very general form of Poincaré duality, which is studied here in detail. Among the technical tools employed are calculations with iterated products in bivariant K-theory and cyclic theory, which are simplified using a novel diagram calculus reminiscent of Feynman diagrams
Self-consistent time-domain large-signal model of traveling-waveelectroabsorption modulators
No full text
Non-invasive ventilation in the postoperative period: Is there a role?
No full textNon-invasive positive pressure ventilation or non-invasive ventilation (NIV) has emerged as a simpler and safer alternative to invasive mechanical ventilation in patients developing acute postoperative respiratory failure. The benefits of NIV as compared to intubation and mechanical ventilation include lower complications, shorter duration of hospital stay, reduced morbidity, lesser cost of treatment and even reduced mortality rates. However, its use may not be uniformly applicable in all patient groups. This article reviews the indications, contraindications and evidence supporting the use of NIV in individual patient groups in the postoperative period. The anaesthesiologist needs to recognise the subset of patients most likely to benefit from NIV therapy so as to apply it most effectively. It is equally important to promptly identify signs of failure of NIV therapy and be prepared to initiate alternate ways of respiratory support. The author searched PubMed and Ovid MEDLINE, without date restrictions. Search terms included Non-invasive ventilation, postoperative and respiratory failure. Foreign literature was included, though only articles with English translation were used
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