2,276 research outputs found
Star Formation in a Stellar Mass Selected Sample of Galaxies to z=3 from the GOODS NICMOS Survey (GNS)
We present a study of the star-forming properties of a stellar mass-selected
sample of galaxies in the GOODS NICMOS Survey (GNS), based on deep Hubble Space
Telescope imaging of the GOODS North and South fields. Using a stellar mass
selected sample, combined with HST/ACS and Spitzer data to measure both UV and
infrared derived star formation rates (SFR), we investigate the star forming
properties of a complete sample of ~1300 galaxies down to log M*=9.5 at
redshifts 1.5<z<3. Eight percent of the sample is made up of massive galaxies
with M*>10^11 Msun. We derive optical colours, dust extinctions, and
ultraviolet and infrared SFR to determine how the star formation rate changes
as a function of both stellar mass and time. Our results show that SFR
increases at higher stellar mass such that massive galaxies nearly double their
stellar mass from star formation alone over the redshift range studied, but the
average value of SFR for a given stellar mass remains constant over this 2 Gyr
period. Furthermore, we find no strong evolution in the SFR for our sample as a
function of mass over our redshift range of interest, in particular we do not
find a decline in the SFR among massive galaxies, as is seen at z < 1. The most
massive galaxies in our sample (log M*>11) have high average SFRs with values,
SFR(UV,corr) = 103+/-75 Msun/yr, yet exhibit red rest-frame (U-B) colours at
all redshifts. We conclude that the majority of these red high-redshift massive
galaxies are red due to dust extinction. We find that A(2800) increases with
stellar mass, and show that between 45% and 85% of massive galaxies harbour
dusty star formation. These results show that even just a few Gyr after the
first galaxies appear, there are strong relations between the global physical
properties of galaxies, driven by stellar mass or another underlying feature of
galaxies strongly related to the stellar mass.Comment: 18 pages, 10 figures, accepted for publication in MNRA
Ion Beam irradiation of copper nitride: electronic vs elastic-collision mechanism
Copper nitride is a metastable material which results very attractive because of their potential to be used in functional device. Cu3 N easily decomposes into Cu and N2 by annealing [1] or irradiation (electron, ions, laser) [2, 3]. Previous studies carried out in N-rich Cu3 N films irradiated with Cu at 42MeV evidence a very efficient sputtering of N whose yield (5×10 3 atom/ion), for a film with a thickness of just 100 nm, suggest that the origin of the sputtering has an electronic nature. This N depletion was observed to be responsible for new phase formation ( Cu2 O) and pure Cu [4
Role of the extended lymphadenectomy in gastric cancer surgery: experience
Although curative resection is the treatment of choice for gastric
cancer, controversy exists about the adequate extent of lymph node dissection
when resection is performed. METHODS: We retrospectively assessed 85 patients who
underwent a limited lymphadenectomy (D1) and 71 who had an extended lymph node
dissection (D2) in a single institution between 1990 and 1998 (median follow-up,
37.3 months). Prognostic factors were assessed by Cox proportional hazard models
adjusted for potential confounders. RESULTS: We found no significant difference
in the length of hospital stay (median, 12.1 and 13.1 days), overall morbidity
(48.2% and 53.5%), or operative mortality (2.3% and 0%) between D1 and D2,
respectively. Five-year survival in the D2 group was longer (50.6%) than in the
D1 group (41.4%) for tumor stages (tumor-node-metastasis) >I. In multivariate
analysis, tumor-node-metastasis stage (hazard ratio for stages >I vs. 0-I, 11.6),
the ratio between invaded and removed lymph nodes, the presence of distant
metastases, Lauren classification, and the extent of lymphadenectomy (hazard
ratio for D1 vs. D2, 2.3; 95% confidence interval, 1.25-4.30) were the only
significant prognostic factors. CONCLUSIONS: Our experience shows that extended
(D2) lymph node dissection improves survival in patients with resected gastric
cancer
Sistemas de acceso venoso central (SAVC) en pacientes pediátricos. Experiencia de seis años
The need for an access to the venous system, in order to infuse chemotherapeutic treatments or parenteral nutrition, has increased the number of central venous access systems (CVAS) implanted in the past years. Between February 1985 and December 1990, 87 devices were implanted in 76 patients (from 11 months to 15 years of age), with a median function time of 349 days (range: 7 to 1887 days). The overall incidence of complications was 0.10 per 10 days of catheterization, with complication rates for infection and thrombosis of 0.02 and 0.03, respectively. Nineteen systems were removed because of complications and 11 because of completion of the treatment. Of the cases, 97.7% included a follow-up period. The present study confirms the advantages of these devices, with a long working life and a low complication rate, being a good alternative for chronically ill children requiring long-term and/or cyclic intravenous therapy
Promoting global clinical care and research for children with orthopaedic disabilities through motion analysis technology
Human motion analysis is a tool used to understand orthopaedic disabilities in children and to plan and monitor treatment strategies. It enables clinicians to quantitatively describe rehabilitative progress, plan surgeries, and conduct research. While this technology is prevalent in major academic medical centers, access is lacking in many regions throughout the world. This paper presents a novel approach to offer more accessible technology at greatly reduced cost. Current applications are underway in the Philippines, Mexico, and Colombia. Through international partnerships, improvements in clinical care, medical education, and research have been observed
Drug repurposing: tolfenamic acid inactivates PrbP, a transcriptional accessory protein in liberibacter asiaticus
CLIBASIA_01510, PrbP, is a predicted RNA polymerase binding protein in Liberibacter asiaticus. PrbP was found to regulate expression of a small subset of ribosomal genes through interactions with the β-subunit of the RNA polymerase and a short, specific sequence on the promoter region. Molecular screening assays were performed to identify small molecules that interact with PrbP in vitro. Chemical hits were analyzed for therapeutic efficacy against L. asiaticus via an infected leaf assay, where the transcriptional activity of L. asiaticus was found to decrease significantly after exposure to tolfenamic acid. Similarly, tolfenamic acid was found to inhibit L. asiaticus infection in highly symptomatic citrus seedlings. Our results indicate that PrbP is an important transcriptional regulator for survival of L. asiaticus in planta, and the chemicals identified by molecular screening assays could be used as a therapeutic treatment for huanglongbing disease.Fil: Gardner, Christopher L.. University of Florida; Estados UnidosFil: Pagliai, Fernando A.. University of Florida; Estados UnidosFil: Pan, Lei. University of Florida; Estados UnidosFil: Bojilova, Lora. University of Florida; Estados UnidosFil: Torino, Maria Ines. University of Florida; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Lorca, Graciela L.. University of Florida; Estados UnidosFil: Gonzalez, Claudio F.. University of Florida; Estados Unido
Compositional, structural and morphological modifications of N-rich Cu3N films induced by irradiation with Cu at 42 MeV
N-rich Cu3N films were irradiated with Cu at 42 MeV in the fluences range from 4 × 1011 to 1 × 1014 cm−2. The radiation-induced changes in the chemical composition, structural phases, surface morphology and optical properties have been characterized as a function of ion fluence, substrate temperature and angle of incidence of the incoming ion by means of ion-beam analysis (IBA), x-ray diffraction, atomic force microscopy, profilometry and Fourier transform infrared spectroscopy techniques. IBA methods reveal a very efficient sputtering of N whose yield (5 × 103 atom/ion) is almost independent of substrate temperature (RT-300 °C) but slightly depends on the incidence angle of the incoming ion. The Cu content remains essentially constant within the investigated fluence range. All data suggest an electronic mechanism to be responsible for the N depletion. The release of nitrogen and the formation of Cu2O and metallic Cu are discussed on the basis of existing models
Spanish study of anticoagulation in haemodialysis
This study's objectives were to determine which anticoagulation
methods are commonly used in patients who are undergoing haemodialysis (HD) in
Spain, on what criteria do they depend, and the consequences arising from their
use. MATERIAL AND METHOD: Ours was a cross-sectional study based on two types of
surveys: a "HD Centre Survey" and a "Patient Survey". The first survey was
answered by 87 adult HD units serving a total of 6093 patients, as well as 2
paediatric units. Among these units, 48.3% were part of the public health system
and the remaining 51.7% units were part of the private health system. The patient
survey analysed 758 patients who were chosen at random from among the
aforementioned 78 HD units. RESULTs: A) HD Centre Survey: The majority of adult
HD units (n=61, 70.2%) used both kinds of heparin, 19 of them (21.8%) only used
LMWH and 7 of them (8%) only used UFH. The most frequently applied criteria for
the use of LMWH were medical indications (83.3% of HD units) and ease of
administration (29.5%). The most frequently used methods for adjusting the dosage
were clotting of the circuit (88.2% of units), bleeding of the vascular access
after disconnection (75.3%), and patient weight (57.6%). B) Patient Survey: The
distribution of the types of heparin used was: UFH: 44.1%, LMWH: 51.5%, and
dialysis without heparin in 4.4% of patients. LMWH was more frequently used in
public medical centres (64.2% of patients) than in private medical centres
(46.1%) (P<.001). LMWH was more frequently used in on-line haemodiafiltration
(HF) than in high-flux HD (P<.001). Antiplatelet agents were given to 45.5% of
patients, oral anticoagulants to 18.4% of patients, and both to 5% of patients.
Additionally, 4.4% of patients had suffered bleeding complications during the
previous week, and 1.9% of patients suffered thrombotic complications. Bleeding
complications were more frequent in patients with oral anticoagulants (P=.001),
although there was no association between the type of heparin and the occurrence
of bleeding or thrombotic complications. CONCLUSIONS: We are able to conclude
that there is a great amount of disparity in the criteria used for the medical
prescription of anticoagulation in HD. It is advisable that each HD unit revise
their own results as well as those from other centres, and possibly to create an
Anticoagulation Guide in Haemodialysis
Spectroscopic variability of two Oe stars
The Oe stars HD45314 and HD60848 have recently been found to exhibit very
different X-ray properties: whilst HD60848 has an X-ray spectrum and emission
level typical of most OB stars, HD45314 features a much harder and brighter
X-ray emission, making it a so-called gamma Cas analogue. Monitoring the
optical spectra could provide hints towards the origin of these very different
behaviours. We analyse a large set of spectroscopic observations of HD45314 and
HD60848, extending over 20 years. We further attempt to fit the H-alpha line
profiles of both stars with a simple model of emission line formation in a
Keplerian disk. Strong variations in the strengths of the H-alpha, H-beta, and
He I 5876 emission lines are observed for both stars. In the case of HD60848,
we find a time lag between the variations in the equivalent widths of these
lines. The emission lines are double peaked with nearly identical strengths of
the violet and red peaks. The H-alpha profile of this star can be successfully
reproduced by our model of a disk seen under an inclination of 30 degrees. In
the case of HD45314, the emission lines are highly asymmetric and display
strong line profile variations. We find a major change in behaviour between the
2002 outburst and the one observed in 2013. This concerns both the relationship
between the equivalent widths of the various lines and their morphologies at
maximum strength (double-peaked in 2002 versus single-peaked in 2013). Our
simple disk model fails to reproduce the observed H-alpha line profiles of
HD45314. Our results further support the interpretation that Oe stars do have
decretion disks similar to those of Be stars. Whilst the emission lines of
HD60848 are explained by a disk with a Keplerian velocity field, the disk of
HD45314 seems to have a significantly more complex velocity field that could be
related to the phenomenon that produces its peculiar X-ray emission.Comment: Accepted for Publication in A&
Serotypes and Clonal Composition of Streptococcus pneumoniae Isolates Causing IPD in Children and Adults in Catalonia before 2013 to 2015 and after 2017 to 2019 Systematic Introduction of PCV13
Clones; Invasive pneumococcal disease; SerotypesClones; Enfermedad neumocócica invasiva; SerotiposClons; Malaltia pneumocòcica invasiva; SerotipsThe goal of this study was to investigate the distribution of serotypes and clonal composition of Streptococcus pneumoniae isolates causing invasive pneumococcal disease (IPD) in Catalonia, before and after systematic introduction of PCV13. Pneumococcal strains isolated from normally sterile sites obtained from patients of all ages with IPD received between 2013 and 2019 from 25 health centers of Catalonia were included. Two study periods were defined: presystematic vaccination period (2013 and 2015) and systematic vaccination period (SVP) (2017 to 2019). A total of 2,303 isolates were analyzed. In the SVP, there was a significant decrease in the incidence of IPD cases in children 5 to 17 years old (relative risk [RR] 0.61; 95% confidence interval [CI] 0.38 to 0.99), while there was a significant increase in the incidence of IPD cases in 18- to 64-year-old adults (RR 1.33; 95% CI 1.16 to 1.52) and adults over 65 years old (RR 1.23; 95% CI 1.09 to 1.38). Serotype 8 was the major emerging serotype in all age groups except in 5- to 17-year-old children. In children younger than 5 years old, the main serotypes in SVP were 24F, 15A, and 3, while in adults older than 65 years they were serotypes 3, 8, and 12F. A significant decrease in the proportions of clonal complexes CC156, CC191, and ST306 and an increase in those of CC180, CC53, and CC404 were observed. A steady decrease in the incidence of IPD caused by PCV13 serotypes indicates the importance and impact of systematic vaccination. The increase of non-PCV13 serotypes highlights the need to expand serotype coverage in future vaccines and rethink vaccination programs for older adults.
IMPORTANCE We found that with the incorporation of the PCV13 vaccine, the numbers of IPD cases caused by serotypes included in this vaccine decreased in all of the age groups. Still, there was an unforeseen increase of the serotypes not included in this vaccine causing IPD, especially in the >65-year-old group. Moreover, a significant increase of serotype 3 included in the vaccine has been observed; this event has been reported by other researchers. These facts call for the incorporation of more serotypes in future vaccines and a more thorough surveillance of the dynamics of this microorganism
- …