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1.
Nature ; 426(6964): 261-4, 2003 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-14628044

RESUMO

Stars with masses in the range 1-8 solar masses (M(\circ)) live ordinary lives for approximately 10(9)-10(10) years, but die extraordinary deaths. First, during their death throes as asymptotic giant branch (AGB) stars they eject, over 10(4)-10(5) years, half or more of their mass in slowly expanding, spherical winds, and then, in a short (a few 100-1,000 years) and poorly understood phase, they are transformed into aspherical planetary nebula. Recent studies support the idea that high-speed, jet-like flows play a crucial role in this transformation. Evidence for such outflows is indirect, however; this phase is so short that few nearby stars are likely to be caught in the act. Here we report the discovery of a newly launched, high-speed jet-like outflow in the nearby AGB star, V Hydrae. We have detected both proper motions and ongoing evolution in the jet. These results support a model in which the jet is driven by an accretion disk around an unseen, compact companion. We also find a central, dense equatorial disk-like structure which may enable and/or enhance the formation of the accretion disk.

2.
Science ; 369(6510): 1497-1500, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32943524

RESUMO

Binary interactions dominate the evolution of massive stars, but their role is less clear for low- and intermediate-mass stars. The evolution of a spherical wind from an asymptotic giant branch (AGB) star into a nonspherical planetary nebula (PN) could be due to binary interactions. We observed a sample of AGB stars with the Atacama Large Millimeter/submillimeter Array (ALMA) and found that their winds exhibit distinct nonspherical geometries with morphological similarities to planetary nebulae (PNe). We infer that the same physics shapes both AGB winds and PNe; additionally, the morphology and AGB mass-loss rate are correlated. These characteristics can be explained by binary interaction. We propose an evolutionary scenario for AGB morphologies that is consistent with observed phenomena in AGB stars and PNe.

3.
Astrophys J ; 860(2)2018 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-30185992

RESUMO

Binarity is believed to dramatically affect the history and geometry of mass loss in AGB and post-AGB stars, but observational evidence of binarity is sorely lacking. As part of a project to search for hot binary companions to cool AGB stars using the GALEX archive, we discovered a late-M star, Y Gem, to be a source of strong and variable UV and X-ray emission. Here we report UV spectroscopic observations of Y Gem obtained with the Hubble Space Telescope that show strong flickering in the UV continuum on time-scales of ≲ 20 s, characteristic of an active accretion disk. Several UV lines with P-Cygni-type profiles from species such as Si IV and C IV are also observed, with emission and absorption features that are red- and blue-shifted by velocities of ~500 km s-1 from the systemic velocity. Our model for these (and previous) observations is that material from the primary star is gravitationally captured by a companion, producing a hot accretion disk. The latter powers a fast outflow that produces blue-shifted features due to absorption of UV continuum emited by the disk, whereas the red-shifted emission features arise in heated infalling material from the primary. The outflow velocities support a previous inference by Sahai et al. (2015) that Y Gem's companion is a low-mass main-sequence star. Blackbody fitting of the UV continuum implies an accretion luminosity of about 13 L⊙, and thus a mass-accretion rate > 5 × 10-7M⊙ yr-1; we infer that Roche lobe overflow is the most likely binary accretion mode for Y Gem.

4.
Astrophys J Lett ; 835(1)2017 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-28191303

RESUMO

We have mapped 12CO J=3-2 and other molecular lines from the "water-fountain" bipolar pre-planetary nebula (PPN) IRAS 16342-3814 with [Formula: see text] resolution using ALMA. We find (i) two very high-speed knotty, jet-like molecular outflows, (ii) a central high-density (> few × 106 cm-3), expanding torus of diameter 1300 AU, and (iii) the circumstellar envelope of the progenitor AGB, generated by a sudden, very large increase in the mass-loss rate to > 3.5 × 10-4M⊙ yr-1 in the past ~455 yr. Strong continuum emission at 0.89 mm from a central source (690 mJy), if due to thermally-emitting dust, implies a substantial mass (0.017 M⊙) of very large (~mm-sized) grains. The measured expansion ages of the above structural components imply that the torus (age~160 yr) and the younger high-velocity outflow (age~110 yr) were formed soon after the sharp increase in the AGB mass-loss rate. Assuming a binary model for the jets in IRAS 16342, the high momentum rate for the dominant jet-outflow in IRAS 16342 implies a high minimum accretion rate, ruling out standard Bondi-Hoyle-Lyttleton wind accretion and wind Roche lobe overflow (RLOF) models with white-dwarf or main-sequence companions. Most likely, enhanced RLOF from the primary or accretion modes operating within common envelope evolution are needed.

5.
Biochim Biophys Acta ; 1428(2-3): 433-45, 1999 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-10434063

RESUMO

A processed oligosaccharide mixture of buffalo milk induced significant stimulation of antibody, delayed-type hypersensitivity response to sheep red blood cells in BALB/c mice. This also stimulated non-specific immune response of the animals measured in terms of macrophage migration index. A novel pentasaccharide has been isolated from the oligosaccharide containing fraction having immunostimulant activity of buffalo milk. This compound was isolated by a combination of gel filtration chromatography, silica gel column chromatography of derivatised oligosaccharides while the homogeneity was confirmed by high performance liquid chromatography. The results of structural analyses, i.e. proton nuclear magnetic resonance, fast atom bombardment mass spectrometry, chemical transformations and degradations are consistent with the following structure: GlcNAcbeta(1-->3)Galbeta(1-->4)GlcNAcbeta(1-->3)Gal beta(1-->4)Glc


Assuntos
Adjuvantes Imunológicos/química , Leite/química , Oligossacarídeos/química , Adjuvantes Imunológicos/isolamento & purificação , Adjuvantes Imunológicos/farmacologia , Animais , Búfalos , Sequência de Carboidratos , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Sistema Imunitário/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Camundongos , Camundongos Endogâmicos BALB C , Dados de Sequência Molecular , Oligossacarídeos/isolamento & purificação , Oligossacarídeos/farmacologia , Espectrometria de Massas de Bombardeamento Rápido de Átomos
6.
Int Immunopharmacol ; 5(6): 937-46, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15829410

RESUMO

In search of a potent immunomodulator to be used as an immunoprophylactic agent and as adjunct to chemotherapy against Leishmania infection, two analogs of muramyl dipeptide, viz. N.Ac-norMur-MeVal-D-isoGln (86/448) and N.AcMur-Acc-D-isoGln (89/729) were evaluated for desired activity. Effect of these peptides on cell mediated and humoral immunity was studied by immunizing the peptide treated mouse with sheep red blood cells (SRBC) and determining HA-titer, plaque forming cells assay and delayed type of hypersensitivity (DTH) response after 4-5 days. Both the peptides stimulated cell mediated immunity (CMI), humoral response as well as macrophage function in terms of super oxide anion (O2-) and nitric oxide (NO) generation. Mitogen induced lymphocyte proliferation and production of IL-2 and INF-gamma increased while that of IL-4 and IL-10 decreased by both the peptides showing a typical Th1 type response. After establishing the immunostimulatory activity, these peptides were evaluated for immunoprophylactic efficacy as well as for use as adjunct to chemotherapy with stibanate (SSG) against Leishmania donovani infection in golden hamster. These peptides were found quite effective in both the modes. In adjunct use the treatment may require lower dose of SSG and thereby reduce the chances of drug toxicity.


Assuntos
Acetilmuramil-Alanil-Isoglutamina/análogos & derivados , Acetilmuramil-Alanil-Isoglutamina/farmacologia , Adjuvantes Imunológicos/farmacologia , Adjuvantes Imunológicos/uso terapêutico , Leishmania donovani , Leishmaniose Visceral/tratamento farmacológico , Acetilmuramil-Alanil-Isoglutamina/uso terapêutico , Animais , Relação CD4-CD8 , Cricetinae , Citocinas/biossíntese , Quimioterapia Combinada , Eritrócitos/imunologia , Leishmaniose Visceral/parasitologia , Leishmaniose Visceral/prevenção & controle , Ativação Linfocitária , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Ovinos/imunologia , Baço/parasitologia , Superóxidos/metabolismo
7.
Int J Surg Case Rep ; 7C: 124-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25465646

RESUMO

INTRODUCTION: Ileostomy is an iatrogenic entero-cutaneous (EC) fistula designed for controlled evacuation of bowel contents. Once ileostomy has served its purpose, it is reverted by surgical procedure. We are reporting an interesting case of spontaneous closure of an ileostomy, obviating the need of surgical intervention. PRESENTATION OF CASE: A 26 year old lady presented with perforation peritonitis. Upon exploration, a tubercular perforation of terminal ileum was found. Loop ileostomy was formed and patient was discharged on anti-tubercular treatment (ATT) after an uneventful recovery. During follow up visits, stoma was found to be retracting gradually. Retraction was not associated with any signs of peritonitis. Patient was able to pass stools per rectally. Stoma regressed completely within 8 months followed by epithelialisation of stoma site. Patient was leading an essentially normal life until her last follow up visit. DISCUSSION: Considering the various factors affecting spontaneous healing of EC fistulas, all the intestinal stomas do have favourable characteristics essential for spontaneous closure. However, this is seldom seen in day to day surgical practice. The factors pertaining to this particular case that led to spontaneous closure of stoma remain poorly understood. CONCLUSION: Further research is warranted to understand the mechanism behind spontaneous regression of a stoma. Relationship between this event and intestinal tuberculosis or ATT needs to be analysed.

8.
Eur J Med Chem ; 36(5): 435-45, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11451532

RESUMO

A number of 3-O-[2'-hydroxy-3'-N,N-aminopropan-1'-yl]-alpha-D-glucofuranoses were synthesised by regioselective oxirane ring opening in compound 2 with different secondary amines followed by selective deacetalisation. All the compounds were tested for their immunomodulatory potential in vitro; seven of them expressed significant immunostimulant activity.


Assuntos
Adjuvantes Imunológicos/síntese química , Adjuvantes Imunológicos/farmacologia , Dissacarídeos/síntese química , Dissacarídeos/imunologia , Glucose/análogos & derivados , Linfócitos/efeitos dos fármacos , Adjuvantes Imunológicos/química , Animais , Cromatografia em Camada Fina , Dissacarídeos/química , Desenho de Fármacos , Glucose/química , Ativação Linfocitária/efeitos dos fármacos , Linfócitos/citologia , Linfócitos/imunologia , Camundongos , Espectroscopia de Luz Próxima ao Infravermelho , Baço , Relação Estrutura-Atividade
9.
Environ Pollut ; 43(2): 91-102, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-15092803

RESUMO

The impact of distillery effluent in various concentrations (1, 2.5, 5, 10, 25, 50, 75 and 100%) on the seed germination, Speed of Germination Index, growth behaviour, leaf area, biomass, net primary productivity, pigment content, reproductive capacity, seed output, seed weight, seed density and the seed protein content of Cicer arietinum L. plants was investigated. The percentage and speed of germination of seeds were increasingly retarded with increase in effluent concentration and at 100% concentration there was no germination. The seedlings exhibited maximum shoot length at 5% concentration and maximum root length at 2.5% concentration. The values of root and shoot lengths, leaf area, biomass, net primary productivity, pigment content, reproductive capacity, seed output, seed weight, seed density and seed protein content in pot plants exhibited a gradual increase from the control up to 5% concentration and decreases at higher concentrations. The very high BOD load and the presence of excessive concentrations of soluble salts could be responsible for the toxicity of the effluent. The effluent at up to 5% concentration was, however, beneficial for the overall growth parameters studied and can thus be used as a liquid fertilizer.

10.
J Ethnopharmacol ; 71(1-2): 89-92, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10904150

RESUMO

Products of certain plants given to mothers after child birth or to invalids were studied for immunostimulant activity using the macrophage migration index (MMI) as a parameter of macrophage activation and cell-mediated immunity and haemagglutinating antibody (HA) titres and plaque-forming cell (PFC) counts as parameters of humoral immunity. Feeding of Prunus amygdalus (Almond(1)) and Buchanania lanzan (Chirronji(1)) significantly stimulated both CMI and humoral immunity in BALB/c mice as evidenced by the enhancement of MMI, HA titres, and PFC counts. Euryale ferox (Tel makhana(1)), Phoenix dactylifera (Chhohara(1)) and Zingiber officinale (Sonth(1)), however, stimulated humoral immunity to a greater extent than CMI. The observation provides scientific basis for feeding the products of above plants to mothers after child birth and to invalids with a relatively poor immune status.


Assuntos
Adjuvantes Imunológicos/farmacologia , Frutas/química , Ayurveda , Plantas Medicinais/química , Animais , Inibição de Migração Celular , Feminino , Hemaglutininas/análise , Técnica de Placa Hemolítica , Índia , Trabalho de Parto , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Gravidez
11.
J Ethnopharmacol ; 56(3): 233-6, 1997 May.
Artigo em Inglês | MEDLINE | ID: mdl-9201614

RESUMO

Pippali Rasayana (PR), an Indian ayurvedic drug prepared from Palash (Butea monosperma (Lamk) Kuntze; Leguminaceae) and Pippali (Piper longum L.; Piperaceae), was administered at a dose of 1 g p.o. three times daily for a period of 15 days to patients (25 treated, 25 placebo controls) suffering from giardiasis with clinical signs and symptoms, and stools positive for trophozoites/cysts of Giardia lamblia. After 15 days of drug treatment there was a complete disappearance of G. lamblia (trophozoites/cysts) from the stools of 23 out of 25 patients. General signs and symptoms of ill health and abdominal discomfort, presence of mucus, pus cells and RBCs were significantly reduced. There was a marked improvement in the clinical and haematological profile of the patients. Spontaneous recovery in 20% cases was recorded in placebo controls.


Assuntos
Giardíase/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Adjuvantes Imunológicos/uso terapêutico , Antiprotozoários/uso terapêutico , Método Duplo-Cego , Fezes/parasitologia , Giardíase/imunologia , Giardíase/parasitologia , Humanos , Índia , Ayurveda
12.
J Forensic Sci ; 46(5): 1025-32, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11569540

RESUMO

A rapid, accurate, precise, reproducible, economical, and environmentally gentle method using capillary electrophoresis (CE) is presented for the routine analysis of methamphetamine, amphetamine, MDA, MDMA, MDEA, and cocaine in seized drugs. The methodology uses a 32 cm by 50 microm capillary (length to detector 23.5 cm) with a commercially available buffer kit and diode array UV detection. Dynamic coating of the capillary surface is accomplished by flushing with base for 1 min, a proprietary polycation for 1 min, and then a proprietary polyanion for 2 min. This approach provides a relatively high and stable electroosmotic flow (EOF), even at low pHs. The background electrolyte (BGE) contains 75 mM phosphate buffer (pH 2.5) with the same polyanion as above. Using this methodology, amphetamine, methamphetamine, MDA, MDMA, MDEA, and an internal standard (n-butylamphetamine) are baseline resolved in less than 5 min. The run-to-run migration time %RSDs and peak area %RSDs are typically <0.3% and <2.1%, respectively. The day-to-day and capillary-to-capillary migration time %RSDs are <1.5% and <2.1%, respectively. The %RSDs of the relative migration times compared with the internal standard on a day-to-day and capillary-to-capillary basis are <0.2% and <0.06%, respectively. The linear dynamic range using peak areas range from 0.003 to 0.10 mg/mL. The correlation coefficients are >0.9998, with all calibration curves passing at or near the origin. Similar data are obtained for cocaine and its internal standard henyltoloxamine. None of the compounds usually encountered in illicit samples interfere with the target compound (e.g., methamphetamine and cocaine) or the internal standard. Quantitative results for synthetic mixtures and seized exhibits are in good agreement with actual values, and also with results obtained from other techniques. The relatively high EOF for the dynamically coated capillary system allows for the screening of basic, acidic, and neutral adulterants in drug seizures; identification is facilitated by the use of automated UV library searches.

13.
Indian J Ophthalmol ; 43(2): 73-4, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8818314

RESUMO

To evaluate the effects of topical timolol on lipid profile, blood samples from 25 patients (16 males and 9 females) were analysed before topical instillation of 0.5% timolol maleate and thereafter at one month and two months. After two months of therapy, the level of high density lipoprotein (HDL) decreased significantly (p < 0.02). The levels of low density lipoprotein (LDL), very low density lipoprotein (VLDL) and triglyceride increased but the changes were not statistically significant. Since low level of HDL is strongly associated with increased risk of myocardial infarction, our study cautions use of topical timolol in patients with low levels of HDL or with previous history of coronary heart disease.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Lipídeos/sangue , Timolol/farmacologia , Administração Tópica , Antagonistas Adrenérgicos beta/administração & dosagem , Adulto , HDL-Colesterol/sangue , LDL-Colesterol/sangue , VLDL-Colesterol/sangue , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Soluções Oftálmicas , Timolol/administração & dosagem , Triglicerídeos/sangue
14.
J Commun Dis ; 16(1): 77-81, 1984 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12055792

RESUMO

Infective larvae (L3) of Dirofilaria immitis were cultivated in various synthetic media. L3 obtained from Aedes aegypti mosquitoes by mass dissection were inoculated into the media, viz: RPMI 1640 medium with 10 per cent human AB serum (medium-A); Tc-199 medium with organic acids, sugars of Grace's insect medium and 10 per cent foetal calf serum (FCS) (medium-B); and Grace's insect medium with 10 per cent FCS (medium-C). Maximum survival of 26 days was found in medium 'A'. Approximately 80 per cent healthy larvae moulted after 72 hours. They increased in size from an initial average length of 1050 microns and 25 microns width to an average 1600 microns length and 35 microns width. Blunting and rounding of anterior ends were conspicuous.


Assuntos
Dirofilaria immitis/crescimento & desenvolvimento , Larva/crescimento & desenvolvimento , Animais , Meios de Cultura/química , Meios de Cultura/farmacologia , Dirofilaria immitis/efeitos dos fármacos , Larva/efeitos dos fármacos
17.
Indian J Ophthalmol ; 22(3): 29-30, 1974 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-4465292
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