172 research outputs found
The desert fireball network: A new camera network in the western Australian Nullarbor
Accepted versio
Detection of an intergalactic meteor particle with the 6-m telescope
On July 28, 2006 the 6-m telescope of the Special Astrophysical Observatory
of the Russian Academy of Sciences recorded the spectrum of a faint meteor. We
confidently identify the lines of FeI and MgI, OI, NI and molecular-nitrogen
N_2 bands. The entry velocity of the meteor body into the Earth's atmosphere
estimated from radial velocity is equal to 300 km/s. The body was several tens
of a millimeter in size, like chondrules in carbon chondrites. The radiant of
the meteor trajectory coincides with the sky position of the apex of the motion
of the Solar system toward the centroid of the Local Group of galaxies.
Observations of faint sporadic meteors with FAVOR TV CCD camera confirmed the
radiant at a higher than 96% confidence level. We conclude that this meteor
particle is likely to be of extragalactic origin. The following important
questions remain open: (1) How metal-rich dust particles came to be in the
extragalactic space? (2) Why are the sizes of extragalactic particles larger by
two orders of magnitude (and their masses greater by six orders of magnitude)
than common interstellar dust grains in our Galaxy? (3) If extragalactic dust
surrounds galaxies in the form of dust (or gas-and-dust) aureoles, can such
formations now be observed using other observational techniques (IR
observations aboard Spitzer satellite, etc.)? (4) If inhomogeneous
extragalactic dust medium with the parameters mentioned above actually exists,
does it show up in the form of irregularities on the cosmic microwave
background (WMAP etc.)?Comment: 9 pages, 6 EPS figure
Bioimprint Mediated Label-Free Isolation of Pancreatic Tumor Cells from a Healthy Peripheral Blood Cell Population
New techniques are required for earlier diagnosis and response to treatment of pancreatic cancer. Here, a label-free approach is reported in which circulating pancreatic tumor cells are isolated from healthy peripheral blood cells via cell bioimprinting technology. The method involves pre-fabrication of pancreatic cell layers and sequential casting of cell surfaces with a series of custom-made resins to produce negative cell imprints. The imprint is functionalized with a combination of polymers to engineer weak attraction to the cells which is further amplified by the increased area of contact with the matching cells. A flow-through bioimprint chip is designed and tested for selectivity toward two pancreatic tumor cell lines, ASPC-1 and Mia-PaCa-2. Healthy human peripheral blood mononuclear cells (PBMCs) are spiked with pancreatic tumor cells at various concentrations. Bioimprints are designed for preferential retention of the matching pancreatic tumor cells and with respect to PBMCs. Tumor bioimprints are capable of capturing and concentrating pancreatic tumor cells from a mixed cell population with increased retention observed with the number of seedings. ASPC-1 bioimprints preferentially retain both types of pancreatic tumor cells. This technology could be relevant for the collection and interrogation of liquid biopsies, early detection, and relapse monitoring of pancreatic cancer patients
Twenty-four vs. forty-eight weeks of re-therapy with interferon alpha 2b and ribavirin in interferon alpha monotherapy relapsers with chronic hepatitis C.
Roughly 50% of patients with chronic hepatitis C, who relapsed after a previous monotherapy with interferon alpha, will respond in a sustained fashion to 24 weeks of re-therapy with the combination of interferon alpha plus ribavirin. Whether prolonging treatment duration to 48 weeks will further increase sustained response rates remains ill defined. In this randomised controlled pilot trial we compared the efficacy and tolerability of a 24 week with that of a 48 week course of combination therapy with interferon alpha and ribavirin in interferon monotherapy relapsers with chronic hepatitis C.
Interferon alpha monotherapy relapsers with chronic hepatitis C were randomised to receive interferon alpha 2b (3 x 3 MIU sc weekly) and oral ribavirin (1000/1200 mg po daily) for either 24 weeks or 48 weeks. Virological response was evaluated by HCV RNA PCR at week 10 (initial response), at the end of treatment (end of- treatment response) and at the end of 24 weeks follow-up (sustained response). Only patients with negative HCV RNA at week 10 continued treatment. Adverse events were recorded at regular intervals.
Thirty-seven patients were enrolled, 19 (6 females, median age 43) in the 24 week and 18 (5 females, median age 40) in the 48 week treatment arm. Baseline characteristics were similar in both groups. At treatment week 10, 12/19 (63%) in the 24 week group and 14/18 (78%) patients in the 48 week group had lost HCV RNA in serum (p = 0.33). All initial responders remained HCV RNA negative throughout the treatment period. Sustained response rates were 10/19 (53%) in the 24 week group and 13/18 (72%) in the 48 week group (p = 0.31). Three patients discontinued treatment early (two due to moderate adverse events, one due to non-compliance). Dose modifications were necessary in 9 patients, 4 in the 24 week and 5 in the 48 week group for anaemia, neutropenia, nausea and depression, respectively.
Prolonging interferon / ribavirin combination therapy in interferon alpha monotherapy relapsers with chronic hepatitis C from 24 to 48 weeks may increase sustained response rates. Larger controlled trials using pegylated interferon alpha and ribavirin in relapsers with chronic hepatitis C seem warranted
Data on 824 fireballs observed by the digital cameras of the European Fireball Network in 2017-2018. I. Description of the network, data reduction procedures, and the catalog
A catalog of 824 fireballs (bright meteors), observed by a dedicated network
of all-sky digital photographic cameras in central Europe in the years
2017-2018 is presented. The status of the European Fireball Network,
established in 1963, is described. The cameras collect digital images of
meteors brighter than an absolute magnitude of about -2 and radiometric light
curves with a high temporal resolution of those brighter than a magnitude ~ -4.
All meteoroids larger than 5 grams, corresponding to sizes of about 2 cm, are
detected regardless of their entry velocity. High-velocity meteoroids are
detected down to masses of about 0.1 gram. The largest observed meteoroid in
the reported period 2017-2018 had a mass of about 100 kg and a size of about 40
cm. The methods of data analysis are explained and all catalog entries are
described in detail. The provided data include the fireball date and time,
atmospheric trajectory and velocity, the radiant in various coordinate systems,
heliocentric orbital elements, maximum brightness, radiated energy, initial and
terminal masses, maximum encountered dynamic pressure, physical classification,
and possible shower membership. Basic information on the fireball spectrum is
available for some bright fireballs (apparent magnitude < -7). A simple
statistical evaluation of the whole sample is provided. The scientific analysis
is presented in an accompanying paper.Comment: accepted in Astronomy and Astrophysic
The Puerto Lapice eucrite fall phenomenon
The fall of the Pu
erto Lápice eucrite
occurred in the afternoon of May 10, 2007,
17h57m20±2s UTC. This impressive daylight bolide
was witnessed by thousands of people from Spain, and
is being carefully studied in the framework of the
Spanish Meteor and Fireball Network (SPMN) in a
similar way that we previously did after the fall of the
Villalbeto de la Peña L6 or
dinary chondrite [1,2]. Unfortunately, there is no video records to our knowledge
of the Puerto Lápice even
t, but some eyewitnesses
were able to take pictures of the persistent train from at
least two different locations. Nocturn astrometric calibrations from both places have been obtained, and
these data together with
in situ
trajectory measurements with theodolite of casual eyewitnesses have allowed to estimate the atmo
spheric trajectory and the
radiant with reasonable accu
racy. A preliminary trajectory reconstruction by the SPMN obtained only two
weeks after the event helped
to recover the first meteorite specimens. The meteorite was presented on June
11, 2007 during the International Conference Meteoroids 2007 in Barcelona. In addition to the fall phenomena, the interest of this bolide lies in the eucrite nature
of the recovered meteorite,
that has been recently reported in the Meteoritical Bulletin [3]. Of the 200
eucrites known until 2000, only 25 correspond to observed falls, but the fall circumstances are poorly
known except in few remarkable cases like e.g. Pasamonte
Benefits and Harms of Electrical Neuromodulation for Chronic Pelvic Pain: A Systematic Review
Context: Patients with chronic pelvic pain (CPP) may have pain refractory to conventional pain management strategies. Neuromodulation could provide relief of pain. /
Objective: To evaluate the benefits and harms of neuromodulation for CPP. /
Evidence acquisition:: A comprehensive search of EMBASE, PUBMED, and SCOPUS was performed for the entire database to January 2018. Studies were selected, data were extracted, and quality was assessed by two independent reviewers. A meta-analysis was used to combine randomized controlled trials (RCTs); otherwise, a narrative analysis was used. /
Evidence synthesis: After screening 1311 abstracts, 36 studies including eight RCTs were identified, enrolling 1099 patients. Studies covered a broad range in terms of phenotypes of CPP and methods of neuromodulation. A meta-analysis was possible for percutaneous tibial nerve stimulation and transcutaneous electrical nerve stimulation, which showed improvement in pain. Only narrative synthesis was possible for other modalities (sacral nerve stimulation, spinal cord stimulation, intravaginal electrical stimulation, and pudendal nerve stimulation) which appeared to reduce pain in patients with CPP. Treatments generally improved quality of life but with variable reporting of adverse events. Many studies showed high risks of bias and confounding. /
Conclusions: While electrical neuromodulation may improve symptoms in CPP, further work is needed with high-quality studies to confirm it. /
Patient summary: Neuromodulation may be useful in reducing pain and improving quality of life in patients with chronic pelvic pain, but more research is needed
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