1,721,141 research outputs found
Nursing visibility: could the I.C.N.P. help?]. Visibilità infermieristica: l’ICNP potrebbe aiutare?
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Binding of ubiquinone to photosynthetic reaction centers. 2: Determination of enthalpy and entropy changes for the binding to the QA site in reverse micelles
No full textThe Q(A) Site binding properties of the purple non-sulfur bacterium Rhodobacter sphaeroides reaction centers solubilized in phospholipid-based reverse micelles have been determined. By means of time-resolved absorbance measurements, the binding of the ubiquinone-10 to the Q(A) Site has been followed at different temperatures and quinone concentrations yielding the relative binding constants. A global fit of the experimental data allowed us to get quite reliable values of the thermodynamic parameters joined to the binding process. Enthalpy and entropy changes obtained for the binding at the Q(A) Site (Delta H degrees(bind) = -75.3 +/- 3.4 kJ mol(-1) and Delta S degrees(bind) = -181 +/- 11 J mol(-1) K-1) confirm that the quinone binding to the primary site is stronger with respect to that at the Q(B) site. A Monte Carlo simulation of both the classical Van't Hoff and global analysis approaches is also presented, showing the higher reliability of the thermodynamic parameters derived with the latter method (uncertainty less than 1% with respect to more than 40% of the Van't Hoff analysis). Such an analysis indicates also that the enthalpy-entropy compensation previously observed through the ubiquinone series is likely due to a statistical artifacts
Caregiver coping with home care ventilated patients a challange for family Nursing .
No full textTampere- Finlandi
PREDATION BY DUGESIA POLYCHROA (PLATYHELMINTHES: TRICLADIDA) PREVENTS THE ESTABLISHMENT OF PHYSA ACUTA (GASTROPODA: PULMONATA) IN HARD-SUBSTRATUM HABITATS
No full textDespite half a century of research on planarian-gastropod interactions, the population-level impact
of planarian predation on littoral pulmonates is not well known.We have quantified the predation of the common
lacustrine planaria Dugesia polychroa Schmidt on the ubiquitous snail Physa acuta Drap., a potential keystone
grazer in benthic littoral communities, in a high-replicate laboratory experiment. Planarian predation
pressure was maintained constant, and experimental populations of P. acuta were size-structured simulating
young-rich small groups (re)colonising the habitat (e.g. after release from predation). D. polychroa caused a
quick (week 2) reduction in the density of hatchlings and juveniles, followed by significant reduction in the
numbers of young (at the onset of reproductive age) and larger, reproductive-age adults (week 3). Planarias
did not have any effect on the size of reproductive-age large adults, but oviposition decreased significantly in
week 2, and all P. acuta populations in planarian-present aquaria went extinct within six weeks. Dugesiidinduced
extinction mainly occurred by precluding population turnover. The results strongly suggest that
active predation by D. polychroa on P. acuta can be high under some environmental conditions, effectively preventing
the (re)establishment of small, colonising populations of P. acuta in hard-substratum habitats
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Planarian (Dugesia polychroa) predation on freshwater gastropod eggs depends on prey species, clutch morphology, and egg size
No full textAbsorption behavior of doxorubicin hydrochloride in visible region in different environments: a combined experimental and computational study
No full textThe experimental absorption measurements in the interval 350-600 nm (Vis), molecular dynamics simulations, quantum-mechanics calculations and an advanced molecular treatment of simulation data are here combined to provide a complete picture of the absorption behavior in the visible portion of the electromagnetic spectrum of the doxorubicin hydrochloride (DX) molecule in different environments. By such an approach, we have shown that it is possible to characterize the effect of the environment on the DX absorption behavior - including the vibronic contributions - as well as to interpret such differences in terms of molecular electronic excited states, which are found to be strongly influenced by the environment
Diel activity cycles of freshwater gastropods under natural light: Patterns adn ecological implications
No full textThough much is known about freshwater snail ecology, their circadian rhythms remain poorly
investigated. Well-fed, stress-free, mid-size adults of six species common in central Italian lakes were exposed
to natural sunlight and photoperiod, and their activity status was recorded at 3-h intervals during a 9-d indoor
experiment. All species exhibited evident diurnal habits despite high individual variability, with middayto-
early-afternoon activity peaks. Activity was correlated with diel light conditions but not with short-term
changes in albedo. The prosobranch Bithynia (=Codiella) leachii and the pulmonates Physa (=Physella) acuta
and Planorbis planorbis were the most active species and exhibited the longest-lasting response to daytime
food addition. The prosobranch Valvata piscinalis exhibited long periods retracted in its shell with the operculum
shut, and the remaining taxa (the pulmonates Galba (=Lymnaea) truncatula and Radix (=Lymnaea)
auricularia) exhibited an intermediate degree of activity. P. acuta was the most active species at night and
exhibited the quicker response to nighttime food addition. Alertedness to (diurnal) predators may be highest
for the highly active P. acuta and P. planorbis, whose antipredator defenses are mainly behavioral. Diel activity
patterns and other ecological characteristics suggest that P. acuta may be favored in food-rich habitats,
while V. piscinalis may not be able to fully exploit food resources, especially if in limiting quantities. All snail
species – and P. acuta in particular – may stimulate periphyton metabolism while keeping its biomass low by
grazing mainly during the time of maximum photosynthesis
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