Monte Carlo simulation of a LSC based on stacked layers of fiber arrays with core-coating different absorbing properties.

In this work, a Monte Carlo ray-tracing model for the simulation and optimization of a fiber Luminescent Solar Concentrator (LSC) based on stacked layers of fiber arrays is developed and validated. The fiber LSC efficiency improvements are compared against a conventional planar LSC. We developed a new model to analyze the performance of different configurations of bulk-doped fibers and fibers constituted by a doped coating and a passive core. These configurations are analyzed also varying fiber packing geometry diameters, and length. Due to the exceptionally low absorption coefficient of the silica fibers (αwg ≈ 10-4 cm-1), concentration factors of up to 1.9 are predicted when dimensions are scaled over 1 m2, which improve more than twice the maximum concentration factor ever reported. These results serve as a preliminary theoretical study for the future development of a new LSC design based on flexible silica micro-fibers coated with Si-QDs doped poly(lauryl methacrylate) (PLMA) layers.

Neurocardiovascular pathology in pre-manifest and early-stage Huntington's disease.

BACKGROUND AND PURPOSE: Cardiovascular events are a major cause of early death in the Huntington's disease (HD) population. Dysautonomia as well as deterioration of circadian rhythms can be detected early in the disease progression and can have profound effects on cardiac health. The aim of the present study was to determine if patients with HD and pre-manifest mutation carriers present a higher risk of cardiovascular disease than non-mutation-carrying controls. METHODS: This was a prospective, cross-sectional, multicentre study of 38 HD mutation carriers (23 pre-manifest and 15 early-stage patients) compared with 38 age- and gender-matched healthy controls. Clinical and epidemiological variables, including the main haematological vascular risk factors, were recorded. Ambulatory blood-pressure monitoring and carotid intima-media thickness (CIMT) measurement were performed to assess autonomic function and as target-organ damage markers. RESULTS: Most (63.2%) patients with HD (86.7% and 47.8%, respectively, of the early-stage and pre-manifest patients) were non-dippers compared with 23.7% of controls (P = 0.001). CIMT values were in the 75th percentile in 46.7% and 43.5%, respectively, of the early-stage and pre-manifest patients, whereas none of the controls presented pathological values (P = 0.001 and P = 0.006, respectively). Nocturnal non-dipping was significantly associated with CIMT values in patients (P = 0.002) but not in controls. CONCLUSIONS: These results suggest that higher cardiovascular risks and target-organ damage are present even in pre-manifest patients. Although larger studies are needed to confirm these findings, clinicians should consider these results in the cardiovascular management of patients with HD.

Dopaminergic agonists in Parkinson's disease.

BACKGROUND: Non-ergoline dopamine agonists (DA) are effective treatments for Parkinson's disease (PD). This review presents the pharmacology, evidence of efficacy and safety profile of pramipexole, ropinirole, and rotigotine, and practical recommendations are given regarding their use in clinical practice. RESULTS: Extended-release formulations of pramipexole and ropinirole and transdermal continuous delivery rotigotine patches are currently available; these may contribute to stabilising of plasma levels. In early PD, the three drugs significantly improve disability scales, delay time to dyskinesia and allow a later introduction of levodopa. In late PD they reduced total 'off'-time, improved Unified Parkinson's Disease Rating Scale (UPDRS) in both 'on' and 'off' state and allowed a reduction in total levodopa dosage. A significant improvement in quality of life scales has also been demonstrated. Extended-release formulations have proved to be non-inferior to the immediate release formulations and are better tolerated (ropinirole). Despite a generally good safety profile, serious adverse events, such as impulse control disorder and sleep attacks, need to be routinely monitored. Although combination therapy has not been addressed in scientific literature, certain combinations, such as apomorphine and another DA, may be helpful. Switching from one DA to another is feasible and safe, although in the first days an overlap of dopaminergic side effects may occur. When treatment with DA is stopped abruptly, dopamine withdrawal syndrome may present. Suspending any DA, especially pramipexole, has been linked to onset of apathy, which may be severe. CONCLUSIONS: New non-ergotine DAs are a valuable option for the treatment of both early and late PD. Despite their good safety profile, serious adverse effects may appear; these effects may have a pathoplastic effect on the course of PD and need to be monitored.

Effect of the current annealing (without and with tensile stress) on the soft magnetic behaviour of Fe73.5-x(Co0.5Ni0.5)xSi13.5B9Nb3Cu1 alloy ribbons (x = 2.5, 5 and 10).

Experimental data on microstructural (crystalline volume fraction, grain size) and magnetic (coercive field) properties in amorphous and nanocrystalline Fe73.5-x(Co0.5Ni0.5)xSi13.5B9Nb3Cu1 alloy ribbons (x = 2.5, 5 and 10) are presented. Nanocrystalline structure was developed by annealing the precursor amorphous ribbons by current annealing (CA) and stress-current-annealing (SA). Microstructural analysis of the treated ribbons using X-ray Diffraction showed a high content of amorphous phase in the bulk. In addition, substantial changes in the crystalline state such as grain size of the samples annealed at different conditions were observed. The alloy composition also affects greatly the grain size,: increasing the (Co,Ni) content leads to higher values of the average grain size. The evolutions of the coercive field with the two kinds of thermal treatment were analysed, allowing us to conclude that the addition of (Co,Ni) tends to reduce the magnetic softness character of the original material, while the treated SA samples show higher coercivities higher than those treated without by CA.

Laser-assisted production of spherical TiO2 nanoparticles in water.

TiO(2) nanoparticles with controllable average diameter have been obtained by laser ablation in water. A monomode ytterbium doped fiber laser (YDFL) was used to ablate a metallic titanium target placed in deionized water. The resulting colloidal solutions were subjected to laser radiation to study the resizing effect. The crystalline phases, morphology and optical properties of the obtained nanoparticles were characterized by means of transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), x-ray energy dispersive spectroscopy (EDS) and UV-vis absorption spectroscopy. The colloidal suspensions produced consisting of titanium dioxide crystalline nanoparticles show almost perfect spherical shape with diameters ranging from 3 to 40 nm. The nanoparticles are polycrystalline and exhibit anatase as well as rutile phases.

Fabrication and Deposition of Copper and Copper Oxide Nanoparticles by Laser Ablation in Open Air.

The proximity of the "post-antibiotic era", where infections and minor injuries could be a cause of death, there are urges to seek an alternative for the cure of infectious diseases. Copper nanoparticles and their huge potential as a bactericidal agent could be a solution. In this work, Cu and Cu oxide nanoparticles were synthesized by laser ablation in open air and in argon atmosphere using 532 and 1064 nm radiation generated by nanosecond and picosecond Nd:YVO4 lasers, respectively, to be directly deposited onto Ti substrates. Size, morphology, composition and the crystalline structure of the produced nanoparticles have been studied by the means of field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), the energy dispersive spectroscopy of X-rays (EDS), selected area electron diffraction (SAED) and X-ray diffraction (XRD). The UV-VIS absorbance of the thin layer of nanoparticles was also measured, and the antibacterial capacity of the obtained deposits tested against Staphylococcus aureus. The obtained deposits consisted of porous coatings composed of copper and copper oxide nanoparticles interconnected to form chain-like aggregates. The use of the argon atmosphere contributed to reduce significantly the formation of Cu oxide species. The synthesized and deposited nanoparticles exhibited an inhibitory effect upon S. aureus.

Continuous fiberizing by laser melting (Cofiblas): Production of highly flexible glass nanofibers with effectively unlimited length.

The development of nanofibers is expected to foster the creation of outstanding lightweight nanocomposites and flexible and transparent composites for applications such as optoelectronics. However, the reduced length of existing nanofibers and nanotubes limits mechanical strengthening and effective manufacturing. Here, we present an innovative method that produces glass nanofibers with lengths that are, effectively, unlimited by the process. The method uses a combination of a high-power laser with a supersonic gas jet. We describe the experimental setup and the physical processes involved, and, with the aid of a mathematical simulation, identify and discuss the key parameters which determine its distinctive features and feasibility. This method enabled the production of virtually unlimited long, solid, and nonporous glass nanofibers that display outstanding flexibility and could be separately arranged and weaved.

Studies of Fe-Cu microwires with nanogranular structure.

We report on the fabrication, and structural and magnetic characterization of Cu(63)Fe(37) microwires with granular structure produced by rapid quenching, using the Tailor-Ulitovsky method, from the immiscible alloys. X-ray diffraction study demonstrated that the structure consists of small (6-45 nm) crystallites of Cu and body centred cubic α-Fe. Magnetic properties have been measured in the range of 5-300 K using a SQUID (superconducting quantum interference device) magnetometer. The temperature dependences of the magnetization measured in a cooling regime when no external magnetic field is applied (zero-field cooling) and in the presence of the field (field cooling) show considerable difference below 20 K. This difference could be related to the presence of small α-Fe grains embedded in the Cu matrix. Those α-Fe grains appear to be blocked at temperatures below that at which the maximum of the magnetization is observed in the low temperature range. Significant magnetoresistance (about 7%) has been found in the samples studied. The shape of the observed dependences is typical of a giant magnetoresistance effect.

Structural and magnetic behaviour of soft magnetic Finemet-type ribbons.

Different kinds of magnetic anisotropies have been induced during the nanocrystallization process of Co- and Ni-rich amorphous ferromagnetic (Finemet) ribbons by the application of a constant stress or an axial magnetic field during the annealing process. Magnetization measurements have evidenced the presence od macroscopic anisotropy in the treated samples. The main goal of this work has been, after a careful DSC study, the structural analysis of the treated ribbons using X-ray Diffraction and Atomic Force Microscopy (AFM), detecting substantial differences in the crystallization state and grain size of the samples depending on the thermal treatment that was carried out. Moreover, AFM measurements revealed in all the treated samples a strong nanocrystallisation of the surface without evidences of amorphous matrix, which contrast with XRD measurements that have shown a high content of amorphous phase in the bulk of the ribbons. Magneto-optical Kerr effect measurements have been performed with the aim to elucidate the complex magnetic behaviour that is expected for the surface of the ribbons, measuring surface hysteresis loops that showed much higher coercive field values than that obtained in the bulk material.

Magnetic and structural properties of glass-coated Heusler-type microwires exhibiting martensitic transformation.

We have studied magnetic and structural properties of the Heusler-type Ni-Mn-Ga glass-coated microwires prepared by Tailor-Ulitovsky technique. As-prepared sample presents magnetoresistance effect and considerable dependence of magnetization curves (particularly magnetization values) on magnetic field attributed to the magnetic and atomic disorder. Annealing strongly affects the temperature dependence of magnetization and Curie temperature of microwires. After annealing of the microwires at 973 K, the Curie temperature was enhanced to about 280 K which is beneficial for the magnetic solid state refrigeration. The observed hysteretic anomalies on the temperature dependences of resistance and magnetization in the as-prepared and annealed samples are produced by the martensitic transformation. The magnetoresistance and magnetocaloric effects have been investigated to illustrate a potential technological capability of studied microwires.

Determinants of survival and hospitalization in older, heart failure patients receiving home healthcare.

INTRODUCTION: Since reported evidence is both scarce and controversial, the objective of this study is to determine the risk factors involved in the prognosis of older patients with heart failure (HF) receiving home healthcare from primary care professionals. METHODS: Retrospective cohort community study was carried out in 52 primary healthcare centers in Barcelona (Spain). A follow-up was performed between January 2009 and December 2012 with 7461 HF patients aged >64years. Information was obtained from primary care electronic medical records containing clinical data, functional and cognitive status, total mortality, and hospital admissions for cardiovascular events. RESULTS: Mortality and hospitalization during follow-up were higher in older, HF patients who received home healthcare than those who did not (HR 1.39, 95% CI 1.22-1.58 and 1.92 95% CI 1.72-2.14, respectively). The most relevant determinants for mortality were male gender (HR 1.40, 95%CI 1.10-1.79), previous hospital admission for HF (HR 1.29 95%CI 1.05-1.60), and severe dependence in activities for daily living (ADL) (HR 1.33, 95%CI 1.06-1.67). In contrast, severely dependent ADL patients were not more frequently hospitalized as a consequence of cardiovascular events (0.97, 95% CI 0.77-1.23). CONCLUSIONS: Due to their greater comorbidity and age, mortality and hospitalization in patients requiring home healthcare were higher than those who did not. Among the HF patients receiving home care, mortality and hospital admissions were higher in men, older patients, and in those previously hospitalized for HF. Severe dependence in ADL determined a higher mortality but was not related to increased hospital admission rates.

Reaction time and rhythm of movement in Huntington's disease.

Huntington disease (HD) is characterized by several hyperkinesias though motor slowness is also another cardinal in this disease. In addition, self-paced timing movements are also disturbed in HD, which may also affect several rhythmic voluntary movements such as gait. Motor slowness can be measured with clinical scales such as the Unified Huntington's Disease Rating Scale (UHDRS) and timed tests, but also with the reaction time (RT) paradigm. We evaluated RT as a measure of motor slowness in 30 patients with genetically confirmed Huntington's disease and 24 control subjects. We also evaluated self-paced timing precision (SPTP) by applying a simple software program devised by our group. Clinical assessment was performed according to the UHDRS, including motor section, total functional capacity (TFC) and cognitive section (verbal fluency test, symbol digit, and Stroop test) The mean values obtained for RT and SPTP were statistically different in HD as compared with those from controls (p<0.0005). We observed a statistically significant correlation between RT and TFC scores (rs=-0.57, p<0.005 Spearman's correlation) and also between SPTP values and TFC scores (rs=-0.40, p<0.05 Spearman's correlation). In addition, RT and SPTP significantly correlated with cognitive scores (including digit symbol, verbal fluency and Stroop tests). Simple tests such as RT and SPTP provide an objective evaluation of motor impairment in HD yielding measures that correlate with clinical assessment and functional disability.

The high prevalence of impulse control behaviors in patients with early-onset Parkinson's disease: A cross-sectional multicenter study.

INTRODUCTION: In Parkinson's disease patients, impulse control disorders (ICDs) have been associated with younger age and early disease onset, yet the prevalence of ICDs in early-onset Parkinson's disease (EOPD) patients has yet to be studied. Thus, we set out to compare the prevalence of impulse control behaviors (ICBs) in a cohort of EOPD patients with that in age and gender matched healthy controls (HCs), as well as to analyze the association of these symptoms with the use of dopaminergic drugs and other clinical or demographic factors. METHODS: A cross-sectional, multicenter study was carried out on patients recruited from outpatient Movement Disorder Clinics, assessing ICBs using the short form of the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP). In addition, depression and quality of life (QoL) were measured, along with other demographic and clinical variables. RESULTS: Of the 87 EOPD patients, 49 (58.3%) displayed an ICB, as did 28 of the 87 HCs (32.9%; p=0.001). Most of the EOPD patients that displayed an ICB (91.8%) were medicated with a dopamine agonist (DA) and accordingly, DA treatment was associated with a 7-fold increased risk of developing an ICB. Patients with ICBs had a higher depression score and a worse QoL. CONCLUSIONS: ICBs are much more prevalent in EOPD patients than in HCs and they are associated with DA intake, depression and a worse QoL.

GMR effect in CuCo annealed melt-spun ribbons.

A thorough microstructural and magnetic analysis has been performed on as-quenched and annealed (475 and 525 degrees C, 1 hour) melt-spun Cu100-xCox (x = 10 and 15) granular alloys, presenting a giant magnetoresistance (GMR) effect. The annealed samples are inhomogeneous with respect to the Co-particle sizes and interparticles distances and, therefore, these particles present superparamagnetic and ferromagnetic behaviours, which determine the GMR response. The samples x = 15, treated at 525 degrees C during 1 hour, presented the best GMR ratio (approximately 5% at room temperature to be the highest value approaching roughly to the saturation under an applied magnetic field of 15 KOe), with the coexistence of Co-particles with both kinds of magnetic behaviour.

[Time-series analysis applied to nosocomial infection]. / Análisis de series temporales aplicado a la infección nosocomial.

BACKGROUND: In this study we introduce a new view of hospital infection, to apply time series techniques to it. Our objective is to complement hospital infection's epidemiological surveillance by means of obtaining alert and alarm thresholds that make easy to the epidemiologist the decision of intervention, in case they are exceeded. METHODS: We have used the classic time series analysis described by Rumeau-Rouquette, and ARIMA (Autoregresive Integrated Moving Average) models developed by Box and Jenkins. The study focus on three hospital units: one intensive care, one long term care and one surgical unit. The nosocomial infection intervals have been calculated with a 68% (1SD) and 95% (2SD) confidence levels. RESULTS: We detect an ascending general trend in the last two units, without the detection of seasonal variations. Two ARIMA (1, 0, 0) models we obtained for surgery and long term care, discarding other better adjusted models, more complex and difficult to obtain, but with no real advantage in prediction power. Confidence intervals were calculated with both methods. We did not find general trend and seasonal variations for intensive care unit. No model was considered valid, because of its high random component. The nosocomial infection intervals have been calculated with mean +/- 1SD and mean +/- 2SD. CONCLUSIONS: We think that more precise knowledge of hospital infection, with a high random component in our study, can be in addition useful to assign priority to human and material resources.

[Chronic calcifying pancreatitis and chronic renal failure]. / Pancreatitis crónica calcificante e insuficiencia renal crónica.

We report a case of chronic calcifying pancreatitis and exocrine pancreatic deficiency in a patient with chronic renal failure under hemodialysis. We analyze the possible relationship between these two entities with special reference to the role of secondary hyperparathyroidism and extraosseous or metastatic calcification.

[Sensitivity of the anal canal: study techniques and results in normal subjects]. / Sensibilidad del canal anal. Técnicas de estudio y resultados en sujetos normales.

AIM: To describe a technique for the study of the anal canal sensitivity to electric and thermal stimulation, and to investigate it prospectively in normal subjects. EXPERIMENTAL DESIGN: Mucosal electrosensitivity and thermal sensation of the anal canal is correlated with motor parameters: perineometry, manometry and electrophysiology. PATIENTS: 41 control subjects (20M & 21F) with normal anorectal anatomophysiology. RESULTS: In the middle anal canal minimum electrosensibility thresholds were present, and they were similar to the thermal profile. A significant impairment in electrosensitivity was observed as a function of age, but no differences between the sexes were found. Lower thresholds were obtained than cold temperatures (p < 0.001). Both tests of sensitivity correlated with pudendal motor parameters. The maximal thermal difference in the anal canal was 0.28 degree C, while the minimal detectable temperature change was 0.46 +/- 0.1 degrees C. CONCLUSIONS: The sensitivity of the anal canal is greatest in the zone of the anal valves and better in response to hot than cold stimulus. As the minimum detectable temperature change has been greater than the difference of temperature between the low and high anal canal, we suggest that discrimination is not possible on the basis of thermal differences.