2,948 research outputs found
OH-selected AGB and post-AGB objects I.Infrared and maser properties
Using 766 compact objects from a survey of the galactic Plane in the 1612-MHz
OH line, new light is cast on the infrared properties of evolved stars on the
TP-AGB and beyond. The usual mid-infrared selection criteria, based on IRAS
colours, largely fail to distinguish early post-AGB stages. A two-colour
diagram from narrower-band MSX flux densities, with bimodal distributions,
provides a better tool to do the latter. Four mutually consistent selection
criteria for OH-masing red PPNe are given, as well as two for early post-AGB
masers and one for all post--AGB masers, including the earliest ones. All these
criteria miss a group of blue, high-outflow post-AGB sources with 60-mum
excess; these will be discussed in detail in Paper II. The majority of post-AGB
sources show regular double-peaked spectra in the OH 1612-MHz line, with fairly
low outflow velocities, although the fractions of single peaks and irregular
spectra may vary with age and mass. The OH flux density shows a fairly regular
relation with the stellar flux and the envelope optical depth, with the maser
efficiency increasing with IRAS colour R21. The OH flux density is linearly
correlated with the 60-mum flux density.Comment: 16 pages, LaTex, 22 figures, AJ (accepted
Raising the accuracy of determination the moment of inertia of rotorsflywheels mechanical gyroscope in method of torsional oscillations
The Effect of Unenhanced MRI on the Surgeons' Decision-Making Process in Females with Suspected Appendicitis
This prospective study evaluated the impact of the results of unenhanced magnetic resonance imaging (MRI) on the surgeon's diagnosis of acute appendicitis in potentially fertile females. 112 female patients, aged 12-55, with suspected appendicitis underwent MRI of the abdomen. At three defined intervals; admission and clinical re-evaluation before and after revealing the MRI results, the surgeon recorded the attendance of each patient in operative treatment, observation or discharge. Appendicitis was confirmed or declined by pathology or by telephone follow-up in case of non-intervention. Appendicitis was confirmed in 29 of 112 patients. At admission the surgeon's disposition had a sensitivity of 97 % and specificity of 29 %. After knowing the MRI results, sensitivity was 97 % and specificity 64 %. The sensitivity and specificity of MRI alone were 89 and 100 %, with a negative and positive predictive value of 96 and 100 %, respectively. We believe that MRI should perhaps be standard in all female patients during their reproductive years with suspected appendicitis. It avoids an operation in 32 % of cases and allows earlier planning for patients with an equivocal clinical picture. Trial number: OND1292733 (Narcis.nl)
TNF- α augments intratumoural concentrations of doxorubicin in TNF- α -based isolated limb perfusion in rat sarcoma models and enhances anti-tumour effects
We have shown previously that isolated limb perfusion (ILP) in sarcoma-bearing rats results in high response rates when melphalan is used in combination with tumour necrosis factor alpha (TNF-α). This is in line with observations in patients. Here we show that ILP with doxorubicin in combination with TNF-α has comparable effects in two different rat sarcoma tumour models. The addition of TNF-α exhibits a synergistic anti-tumour effect, resulting in regression of the tumour in 54% and 100% of the cases for the BN175-fibrosarcoma and the ROS-1 osteosarcoma respectively. The combination is shown to be mandatory for optimal tumour response. The effect of high dose TNF-α on the activity of cytotoxic agents in ILP is still unclear. We investigated possible modes by which TNF-α could modulate the activity of doxorubicin. In both tumour models increased accumulation of doxorubicin in tumour tissue was found: 3.1-fold in the BN175 and 1.8-fold in the ROS-1 sarcoma after ILP with doxorubicin combined with TNF-α in comparison with an ILP with doxorubicin alone. This increase in local drug concentration may explain the synergistic anti-tumour responses after ILP with the combination. In vitro TNF-α fails to augment drug uptake in tumour cells or to increase cytotoxicity of the drug. These findings make it unlikely that TNF-α directly modulates the activity of doxorubicin in vivo. As TNF-α by itself has no or only minimal effect on tumour growth, an increase in local concentrations of chemotherapeutic drugs might well be the main mechanism for the synergistic anti-tumour effects. © 2000 Cancer Research Campaig
H2O Maser Observations of Candidate Post-AGB Stars and Discovery of Three High-velocity Water Sources
We present the results of 22 GHz H_2O maser observations of a sample of 85
post-Asymptotic Giant Branch (post-AGB) candidate stars, selected on the basis
of their OH 1612 MHz maser and far-infrared properties. All sources were
observed with the Tidbinbilla 70-m radio telescope and 21 detections were made.
86 GHz SiO Mopra observations of a subset of the sample are also presented. Of
the 21 H_2O detections, 15 are from sources that are likely to be massive AGB
stars and most of these show typical, regular H_2O maser profiles. In contrast,
nearly all the detections of more evolved stars exhibited high-velocity H_2O
maser emission. Of the five sources seen, v223 (W43A, IRAS 18450-0148) is a
well known `water-fountain' source which belongs to a small group of post-AGB
stars with highly collimated, high-velocity H_2O maser emission. A second
source in our sample, v270 (IRAS 18596+0315), is also known to have
high-velocity emission. We report the discovery of similar emission from a
further three sources, d46 (IRAS 15445-5449), d62 (IRAS 15544-5332) and b292
(IRAS 18043-2116). The source d46 is an evolved post-AGB star with highly
unusual maser properties. The H_2O maser emission from d62 is probably
associated with a massive star. The source b292 is a young post-AGB star that
is highly likely to be a water-fountain source, with masers detected over a
velocity range of 210 km s^{-1}.Comment: 47 pages, 9 figures, 4 tables, accepted by Ap
Sensory processing deficiencies in patients with borderline personality disorder who experience auditory verbal hallucinations
Auditory verbal hallucinations (AVH) are common in patients with borderline personality disorder (BPD). We examined two candidate mechanisms of AVH in patients with BPD, suggested to underlie sensory processing systems that contribute to psychotic symptoms in patients with schizophrenia; sensory gating (P50 ratio and P50 difference) and change detection (mismatch negativity; MMN). Via electroencephalographic recordings P50 amplitude, P50 ratio, P50 difference and MMN amplitude were compared between 23 borderline patients with and 25 without AVH, and 26 healthy controls. Borderline patients with AVH had a significantly lower P50 difference compared with healthy controls, whereas no difference was found between borderline patients without AVH and healthy controls. The groups did not differ on MMN amplitude. The impaired sensory gating in patients with borderline personality disorder who experience AVH implies that P50 sensory gating deficiencies may underlie psychotic vulnerability in this specific patient group. Patients with borderline personality disorder with or without AVH did not have problems with auditory change detection. This may explain why they are spared from the poor outcome associated with negative symptoms and symptoms of disorganization in patients with chronic schizophrenia
Экспериментальные исследования интенсификации процессов теплообмена в энергетических котлах
Запропонована конструктивна схема удосконалення газорозподільних решітки, створено лабораторний стенд і проведені експериментальні дослідження в результаті яких отримані умови, які сприяють збільшенню відносної швидкості руху часток і середовища, створенню додаткової турбулентності потоку середовища, збільшенню кратності оновлення і формування міжфазної поверхні, що може привести до значного прискорення тепло- і масо переносу.The propose a design scheme to improve the gas distribution grid, established a laboratory bench and experimental studies have been obtained as a result of conditions that contribute to an increase in the relative velocity of the particles and the environment, creating more turbulence of flow, increasing the multiplicity of updating and the formation of the interphase surface, which can lead to a significant acceleration heat and mass transfer
Manchester triage system in paediatric emergency care: prospective observational study
Objective To validate use of the Manchester triage system in paediatric emergency care
Immobilisation versus immediate mobilisation after intrauterine insemination: randomised controlled trial
Objective To evaluate the effectiveness of 15 minutes of immobilisation versus immediate mobilisation after intrauterine insemination
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