178 research outputs found
Pneumothorax complicating port-a-cath and Groshong catheter positioning in children : our experience before routine ultrasound-guided puncture
ABSTRACT
Objective: To study incidence and management of long term central venous catheter (CVC) placement related pneu- mothorax (PNX) in children. Aim: To construct a baseline value before the introduction of systematic use of ultrasound guidance, which requires specific training and equipment. Background: Anesthesia Service and Pediatric Oncology of the Italian National Cancer Center; patients were children (age 64 18 years) with solid tumors, needing long-term central venous catheters (Groshong or Port-a-Cath). Materials/Methods: Catheter placement was performed, mostly under general anesthesia, utilizing a micropuncture 5 - 7 Fr needle and fluoroscopy. In the study period ultrasound was used only in case of previously failed attempts. Relevant data were collected retrospectively. Results: From August 2008 to December 2011, 452 catheters were implanted to our patients. The prevalent approach was from subclavian vein (left 85.7%, right 9.7%); in few cases internal jugular vein was chosen (right 2.4%, left 2.2%). Pneumothorax occurred in 14 patients (3.1%; 95%CI 1.9 - 5.1). In 4/14 children the PNX was considered minimal and not treated. In 10 patients the PNX was drained. In 7 cases a traditional, surgical thoracostomy was performed, while in 3 children a 14-Ga polyure- thane catheter (Arrow International\uae) was inserted over a wire guide in the pleural space by anaesthetists. Conclusions: In our centre rates of PNX are the same as those described in literature and are expected to lower when ultrasound guid- ance of the puncture will be routinely applied. Percutaneous drainage of PNX seems as effective as surgically placed thoracostomy catheter, but less invasive
Crypto-unitary forms of quantum evolution operators
For the description of quantum evolution, the use of a manifestly
time-dependent quantum Hamiltonian
is shown equivalent to the work with its simplified, time-independent
alternative . A tradeoff analysis is performed recommending
the latter option. The physical unitarity requirement is shown fulfilled in a
suitable ad hoc representation of Hilbert space.Comment: 15 p
The half-lives for 24Na, 72Ga and 140La
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22610/1/0000160.pd
One particle spectral weight of the three dimensional single band Hubbard model
Dynamic properties of the three-dimensional single-band Hubbard model are
studied using Quantum Monte Carlo combined with the maximum entropy technique.
At half-filling, there is a clear gap in the density of states and well-defined
quasiparticle peaks at the top (bottom) of the lower (upper) Hubbard band. We
find an antiferromagnetically induced weight above the naive Fermi momentum.
Upon hole doping, the chemical potential moves to the top of the lower band
where a robust peak is observed. Results are compared with spin-density-wave
(SDW) mean-field and self consistent Born approximation results, and also with
the infinite dimensional Hubbard model, and experimental photoemission (PES)
for three dimensional transition-metal oxides.Comment: 11 pages, REVTeX, 16 figures included using psfig.sty. Ref.30
correcte
Antiferromagnetism and single-particle properties in the two-dimensional half-filled Hubbard model: a non-linear sigma model approach
We describe a low-temperature approach to the two-dimensional half-filled
Hubbard model which allows us to study both antiferromagnetism and
single-particle properties. This approach ignores amplitude fluctuations of the
antiferromagnetic (AF) order parameter and is valid below a crossover
temperature which marks the onset of AF short-range order. Directional
fluctuations (spin waves) are described by a non-linear sigma model
(NLM) that we derive from the Hubbard model. At zero temperature and
weak coupling, our results are typical of a Slater antiferromagnet. The AF gap
is exponentially small; there are well-defined Bogoliubov quasi-particles
(QP's) (carrying most of the spectral weight) coexisting with a high-energy
incoherent excitation background. As increases, the Slater antiferromagnet
progressively becomes a Mott-Heisenberg antiferromagnet. The Bogoliubov bands
evolve into Mott-Hubbard bands separated by a large AF gap. A significant
fraction of spectral weight is transferred from the Bogoliubov QP's to
incoherent excitations. At finite temperature, there is a metal-insulator
transition between a pseudogap phase at weak coupling and a Mott-Hubbard
insulator at strong coupling. Finally, we point out that our results
straightforwardly translate to the half-filled attractive Hubbard model, where
the charge and pairing fluctuations combine to
form an order parameter with SO(3) symmetry.Comment: Revtex4, 19 pages, 14 figures; (v2) final version as publishe
A novel enzymatically-mediated drug delivery carrier for bone tissue engineering applications: combining biodegradable starch-based microparticles and differentiation agents
In many biomedical applications, the performance
of biomaterials depends largely on their degradation
behavior. For instance, in drug delivery applications, the
polymeric carrier should degrade under physiological
conditions slowly releasing the encapsulated drug. The aim
of this work was, therefore, to develop an enzymaticmediated
degradation carrier system for the delivery of
differentiation agents to be used in bone tissue engineering
applications. For that, a polymeric blend of starch with
polycaprolactone (SPCL) was used to produce a microparticle
carrier for the controlled release of dexamethasone
(DEX). In order to investigate the effect of enzymes on the
degradation behavior of the developed system and release
profile of the encapsulated osteogenic agent (DEX), the
microparticles were incubated in phosphate buffer solution
in the presence of a-amylase and/or lipase enzymes (at
physiological concentrations), at 37 C for different periods
of time. The degradation was followed by gravimetric
measurements, scanning electron microscopy (SEM) and
Fourier transformed infrared (FTIR) spectroscopy and the
release of DEX was monitored by high performance liquid
chromatography (HPLC). The developed microparticles
were shown to be susceptible to enzymatic degradation, as observed by an increase in weight loss and porosity with
degradation time when compared with control samples
(incubation in buffer only). For longer degradation times,
the diameter of the microparticles decreased significantly
and a highly porous matrix was obtained. The in vitro
release studies showed a sustained release pattern with
48% of the encapsulated drug being released for a period of
30 days. As the degradation proceeds, it is expected that
the remaining encapsulated drug will be completely
released as a consequence of an increasingly permeable
matrix and faster diffusion of the drug. Cytocompatibility
results indicated the possibility of the developed microparticles
to be used as biomaterial due to their reduced
cytotoxic effects
Towards the high-accuracy determination of the 238U fission cross section at the threshold region at CERN - N-TOF
The 238U fission cross section is an international standard beyond 2 MeV where the fission plateau starts. However, due to its importance in fission reactors, this cross-section should be very accurately known also in the threshold region below 2 MeV. The 238U fission cross section has been measured relative to the 235U fission cross section at CERN - n-TOF with different detection systems. These datasets have been collected and suitably combined to increase the counting statistics in the threshold region from about 300 keV up to 3 MeV. The results are compared with other experimental data, evaluated libraries, and the IAEA standards
Herschel observations of EXtra-Ordinary Sources (HEXOS): detecting spiral arm clouds by CH absorption lines
We have observed CH absorption lines (J = 3/2, N = 1 ← J = 1/2, N = 1) against the continuum source Sgr B2(M) using the Herschel/HIFI
instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities
and line widths are detected and identified. The narrower line width and lower column density clouds show “spiral arm” cloud characteristics,
while the absorption component with the broadest line width and highest column density corresponds to the gas from the Sgr B2 envelope. The
observations show that each “spiral arm” harbors multiple velocity components, indicating that the clouds are not uniform and that they have internal
structure. This line-of-sight through almost the entire Galaxy offers unique possibilities to study the basic chemistry of simple molecules in
diffuse clouds, as a variety of different cloud classes are sampled simultaneously. We find that the linear relationship between CH and H2 column
densities found at lower AV by UV observations does not continue into the range of higher visual extinction. There, the curve flattens, which
probably means that CH is depleted in the denser cores of these clouds
Fungal diversity notes 253–366: taxonomic and phylogenetic contributions to fungal taxa
Notes on 113 fungal taxa are compiled in this paper, including 11 new genera, 89 new species, one new subspecies, three new combinations and seven reference specimens. A wide geographic and taxonomic range of fungal taxa are detailed. In the Ascomycota the new genera Angustospora (Testudinaceae), Camporesia (Xylariaceae), Clematidis, Crassiparies (Pleosporales genera incertae sedis), Farasanispora, Longiostiolum (Pleosporales genera incertae sedis), Multilocularia (Parabambusicolaceae), Neophaeocryptopus (Dothideaceae), Parameliola (Pleosporales genera incertae sedis), and Towyspora (Lentitheciaceae) are introduced. Newly introduced species are Angustospora nilensis, Aniptodera aquibella, Annulohypoxylon albidiscum, Astrocystis thailandica, Camporesia sambuci, Clematidis italica, Colletotrichum menispermi, C. quinquefoliae, Comoclathris pimpinellae, Crassiparies quadrisporus, Cytospora salicicola, Diatrype thailandica, Dothiorella rhamni, Durotheca macrostroma, Farasanispora avicenniae, Halorosellinia rhizophorae, Humicola koreana, Hypoxylon lilloi, Kirschsteiniothelia tectonae, Lindgomyces okinawaensis, Longiostiolum tectonae, Lophiostoma pseudoarmatisporum, Moelleriella phukhiaoensis, M. pongdueatensis, Mucoharknessia anthoxanthi, Multilocularia bambusae, Multiseptospora thysanolaenae, Neophaeocryptopus cytisi, Ocellularia arachchigei, O. ratnapurensis, Ochronectria thailandica, Ophiocordyceps karstii, Parameliola acaciae, P. dimocarpi, Parastagonospora cumpignensis, Pseudodidymosphaeria phlei, Polyplosphaeria thailandica, Pseudolachnella brevifusiformis, Psiloglonium macrosporum, Rhabdodiscus albodenticulatus, Rosellinia chiangmaiensis, Saccothecium rubi, Seimatosporium pseudocornii, S. pseudorosae, Sigarispora ononidis and Towyspora aestuari. New combinations are provided for Eutiarosporella dactylidis (sexual morph described and illustrated) and Pseudocamarosporium pini. Descriptions, illustrations and / or reference specimens are designated for Aposphaeria corallinolutea, Cryptovalsa ampelina, Dothiorella vidmadera, Ophiocordyceps formosana, Petrakia echinata, Phragmoporthe conformis and Pseudocamarosporium pini. The new species of Basidiomycota are Agaricus coccyginus, A. luteofibrillosus, Amanita atrobrunnea, A. digitosa, A. gleocystidiosa, A. pyriformis, A. strobilipes, Bondarzewia tibetica, Cortinarius albosericeus, C. badioflavidus, C. dentigratus, C. duboisensis, C. fragrantissimus, C. roseobasilis, C. vinaceobrunneus, C. vinaceogrisescens, C. wahkiacus, Cyanoboletus hymenoglutinosus, Fomitiporia atlantica, F. subtilissima, Ganoderma wuzhishanensis, Inonotus shoreicola, Lactifluus armeniacus, L. ramipilosus, Leccinum indoaurantiacum, Musumecia alpina, M. sardoa, Russula amethystina subp. tengii and R. wangii are introduced. Descriptions, illustrations, notes and / or reference specimens are designated for Clarkeinda trachodes, Dentocorticium ussuricum, Galzinia longibasidia, Lentinus stuppeus and Leptocorticium tenellum. The other new genera, species new combinations are Anaeromyces robustus, Neocallimastix californiae and Piromyces finnis from Neocallimastigomycota, Phytophthora estuarina, P. rhizophorae, Salispina, S. intermedia, S. lobata and S. spinosa from Oomycota, and Absidia stercoraria, Gongronella orasabula, Mortierella calciphila, Mucor caatinguensis, M. koreanus, M. merdicola and Rhizopus koreanus in Zygomycota
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