516 research outputs found
Xerostomia induced by radiotherapy: an overview of the physiopathology, clinical evidence, and management of the oral damage
Background: The irradiation of head and neck cancer (HNC) often causes damage to the salivary glands. The resulting salivary gland hypofunction and xerostomia seriously reduce the patient\u2019s quality of life.
Purpose: To analyze the literature of actual management strategies for radiation-induced hypofunction and xerostomia in HNC patients.
Methods: MEDLINE/PubMed and the Cochrane Library databases were electronically evaluated for articles published from January 1, 1970, to June 30, 2013. Two reviewers independently screened and included papers according to the predefined selection criteria.
Results: Sixty-one articles met the inclusion criteria. The systematic review of the literature suggests that the most suitable methods for managing the clinical and pathophysiological consequences of HNC radiotherapy might be the pharmacological approach, for example, through the use of cholinergic agonists when residual secretory capacity is still present, and the use of salivary substitutes. In addition, a modified diet and the patient\u2019s motivation to enhance oral hygiene can lead to a significant improvement.
Conclusion: Radiation-induced xerostomia could be considered a multifactorial disease. It could depend on the type of cancer treatment and the cumulative radiation dose to the gland tissue. A preventive approach and the correct treatment of the particular radiotherapeutic patient can help to improve the condition of xerostomia
Bioleaching of Valuable Elements from Red Mud: A Study on the Potential of Non-Enriched Biomass
Red mud (RM) is the main residue produced by the alkaline extraction of alumina (Al2O3) from bauxite, and it contains valuable metals such as iron (Fe), aluminium (Al), titanium (Ti), magnesium (Mg), manganese (Mn), rare earth elements, etc. This research aimed to investigate the biologically induced leaching of some valuable elements from raw RM without preliminary biomass enrichment and inoculum, simultaneously reducing RM polluting potential and extracting metals for their subsequent recovery within a circular economy-based approach. In addition to the missing inoculum, such an approach is challenging since high RM alkalinity and pH, as well as the absence of any sulphides, constrain the use of the most common biohydrometallurgical techniques. Red Muds from two European locations were tested (RM-I and RM-II, respectively). Bioleaching tests were performed at different temperatures (T = 22 & DEG;C and 28 & DEG;C; and also 15 & DEG;C for RM-II) and solid-to-liquid ratios (S/L = 2%, 5%). A sudden drop in pH from alkaline to constant neutral/acidic values was observed in almost all tests, and such results were attributed to biological activity since abiotic tests did not show any pH decrease. The best results in terms of extraction were achieved with RM-II, in particular for Al, Mg and Mn (17%, 42% and 47%, respectively). At 2% S/L, the highest temperature allowed for a better metal release, while at 5% S/L, the highest extraction of Al, Mg and Ti was observed at 22 & DEG;C. As expected, iron was less available to leach at the achieved pH values, as it was mostly present as hematite in both RMs. Finally, the first microbiological characterisation of the autochthonous biomass selected during the bioleaching treatment of RM was provided
Dynamics of Quasi-ordered Structure in a Regio-regulated pi-Conjugated Polymer:Poly(4-methylthiazole-2,5-diyl)
Dynamics of regio-regulated Poly(4-methylthiazole-2,5-diyl) [HH-P4MeTz] was
inves tigated by solid-state 1H, 2D, 13C NMR spectroscopies, and differential
scanning calorimetry(DSC) measurements. DSC, 2D quadrupolar echo NMR, 13C
cross-polarization and magic-angle spinning(CPMAS) NMR, and 2D spin-echo(2DSE)
CPMAS NMR spectroscopy suggest existence of a quasi-ordered phase in which
backbone twists take place with weakened pi-stackings. Two-dimensional exchange
2D NMR(2DEX) detected slow dynamics with a rate of an order of 10^2Hz for the
CD_3 group in d_3-HH-P4MeTz at 288K. The frequency dependence of proton
longitudinal relaxation rate at 288K shows a omega^-1/2 dependence, which is
due to the one-dimensional diffusion-like motion of backbone conformational
modulation waves. The diffusion rate was estimated as 3+/-2 GHz, which was
approximately 10^7 times larger than that estimated by 2DEX NMR measurements.
These results suggest that there exists anomalous dispersion of modulation
waves in HH-P4MeTz. The one-dimensional group velocity of the wave packet is
responsible for the behavior of proton longitudinal relaxation time. On the
other hand, the 2DEX NMR is sensitive to phase velocity of the nutation of
methyl groups that is associated with backbone twists. From proton T_1 and T_2
measurements, the activation energy was estimated as 2.9 and 3.4 kcal/mol,
respectively. These were in agreement with 3.0 kcal/mol determined by
Moller-Plesset(MP2) molecular orbital(MO) calculation. We also performed
chemical shielding calculation of the methyl-carbon in order to understand
chemical shift tensor behavior, leading to the fact that a quasi-ordered phase
coexist with the crystalline phase.Comment: 14 pages, 11 figures, to appear in Phys.Rev.
The High Time Resolution Universe Survey - V: Single-pulse energetics and modulation properties of 315 pulsars
We report on the pulse-to-pulse energy distributions and phase-resolved
modulation properties for catalogued pulsars in the southern High Time
Resolution Universe intermediate-latitude survey. We selected the 315 pulsars
detected in a single-pulse search of this survey, allowing a large sample
unbiased regarding any rotational parameters of neutron stars. We found that
the energy distribution of many pulsars is well-described by a log-normal
distribution, with few deviating from a small range in log-normal scale and
location parameters. Some pulsars exhibited multiple energy states
corresponding to mode changes, and implying that some observed "nulling" may
actually be a mode-change effect. PSRJ1900-2600 was found to emit weakly in its
previously-identified "null" state. We found evidence for another state-change
effect in two pulsars, which show bimodality in their nulling time scales; that
is, they switch between a continuous-emission state and a single-pulse-emitting
state. Large modulation occurs in many pulsars across the full integrated
profile, with increased sporadic bursts at leading and trailing sub-beam edges.
Some of these high-energy outbursts may indicate the presence of "giant pulse"
phenomena. We found no correlation with modulation and pulsar period, age, or
other parameters. Finally, the deviation of integrated pulse energy from its
average value was generally quite small, despite the significant phase-resolved
modulation in some pulsars; we interpret this as tenuous evidence of energy
regulation between distinct pulsar sub-beams.Comment: Before full MNRAS publication, supplementary material is available
temporarily at http://dl.dropbox.com/u/22076931/supplementary_material.pd
Transformation of a Star into a Planet in a Millisecond Pulsar Binary
Millisecond pulsars are thought to be neutron stars that have been spun-up by
accretion of matter from a binary companion. Although most are in binary
systems, some 30% are solitary, and their origin is therefore mysterious. PSR
J1719-1438, a 5.7 ms pulsar, was detected in a recent survey with the Parkes
64m radio telescope. We show that it is in a binary system with an orbital
period of 2.2 h. Its companion's mass is near that of Jupiter, but its minimum
density of 23 g cm suggests that it may be an ultra-low mass carbon
white dwarf. This system may thus have once been an Ultra Compact Low-Mass
X-ray Binary, where the companion narrowly avoided complete destruction.Comment: 16 pages, 3 figures. Science Express, in pres
Epidemiología de las fracturas de la extremidad proximal del fémur en asturias
Hemos realizado un estudio epidemiológico de las fracturas de fémur proximal
en personas mayores de 50 años, atendidas en nuestro Hospital durante los años 1990-92.
Se valoraron un total de 355 casos. En el período estudiado se observó que las fracturas más
numerosas fueron la cervicales, no encontrando diferencias significativas en los ingresos según
el período estacional. La edad media de presentación fue de 81 años. La tasa de incidencia
fue muy semejante a las otras provincias españolas y menor que la encontrada en los países
del Norte de Europa, Inglaterra y Estados Unidos.We have performed an epidemiologic study on the incidence of proximal femoral
fractures in patients older than 50 years, all reviewed in our Hospital from 1990 to 1992.
We included 355 patients. Femoral neek fractures were the most frequent lesions. No significant
differences in the hospital admissions were found during all the year's seasons. The mean
age of presentation was 81 years. The incidence rate was similar to the rest of Spain, and less
than in North Europe, England and United States
Coordination Chemistry and Sensing Properties Towards Anions and Metal Ions of a Simple Fluorescent Urea
The coordination and sensing properties towards anions and transition metal ions of the simple novel fluorescent urea 1-(2-aminophenyl)-3-(naphthalen-1)-yl)urea (L) were investigated in solution, and in the solid state. An electron donating amine group in the molecular skeleton of L decreased the acidity of the urea NHs that are usually deprotonated by basic anions and allowed for a good degree of affinity towards fluoride in DMSO-d6-0.5 %H2O. Moreover, the amine moiety acted as a further binding group for metal ions. Indeed, L was able to bind Zn2+ both in solution and in the solid state, and to respond to the presence of this metal ion in MeCN with an enhancement of the fluorescence emission. Although solution studies evidenced the formation of a 1 : 1 complex of L with Zn2+, complexes with a 2 : 1 ligand-to-metal stoichiometry were isolated in the solid state. DFT calculations helped to clarify the stability reasons behind these results
Effect of beetroot juice supplementation on aerobic response during swimming
The beneficial effects of beetroot juice supplementation (BJS) have been tested during cycling, walking, and running. The purpose of the present study was to investigate whether BJS can also improve performance in swimmers. Fourteen moderately trained male master swimmers were recruited and underwent two incremental swimming tests randomly assigned in a pool during which workload, oxygen uptake (VO2), carbon dioxide production (VCO2), pulmonary ventilation (VE), and aerobic energy cost (AEC) of swimming were measured. One was a control swimming test (CSW) and the other a swimming test after six days of BJS (0.5l/day organic beetroot juice containing about 5.5 mmol of NO3 -). Results show that workload at anaerobic threshold was significantly increased by BJS as compared to the CSW test (6.3 ± 1 and 6.7 ± 1.1 kg during the CSW and the BJS test respectively). Moreover, AEC was significantly reduced during the BJS test (1.9 ± 0.5 during the SW test vs. 1.7 ± 0.3 kcal·kg-1·h-1 during the BJS test). The other variables lacked a statistically significant effect with BJS. The present investigation provides evidence that BJS positively affects performance of swimmers as it reduces the AEC and increases the workload at anaerobic threshold
A filter-based cross-sectional analysis of an HIV-positive, HAART-treated cohort in rural Burundi: pharmacokinetics, pharmacogenetics and viral load
The High Time Resolution Universe Pulsar Survey I: System configuration and initial discoveries
We have embarked on a survey for pulsars and fast transients using the
13-beam Multibeam receiver on the Parkes radio telescope. Installation of a
digital backend allows us to record 400 MHz of bandwidth for each beam, split
into 1024 channels and sampled every 64 us. Limits of the receiver package
restrict us to a 340 MHz observing band centred at 1352 MHz. The factor of
eight improvement in frequency resolution over previous multibeam surveys
allows us to probe deeper into the Galactic plane for short duration signals
such as the pulses from millisecond pulsars. We plan to survey the entire
southern sky in 42641 pointings, split into low, mid and high Galactic latitude
regions, with integration times of 4200, 540 and 270 s respectively.
Simulations suggest that we will discover 400 pulsars, of which 75 will be
millisecond pulsars. With ~30% of the mid-latitude survey complete, we have
re-detected 223 previously known pulsars and discovered 27 pulsars, 5 of which
are millisecond pulsars. The newly discovered millisecond pulsars tend to have
larger dispersion measures than those discovered in previous surveys, as
expected from the improved time and frequency resolution of our instrument.Comment: Updated author list. 10 pages, 7 figures. For publication in MNRA
- …