Structural and spectral characterisation of Er3+ and Nd3+ doped Ga-La-S-Se glasses.

In this work, the spectroscopy of Er3+ and Nd3+ doped Se-GLS glasses was studied. A structural comparison between doped and non-doped samples was done to assess the differences between the glasses. For this comparison, Raman spectroscopy and thermal analysis were employed. The spectral properties of the samples were studied in order to identify the mechanisms responsible for quenching the fluorescence lifetime of the dopants. In particular, cross-relaxation and concentration quenching were observed in Nd3+ doped samples, whilst co-operative upconversion, radiation trapping and concentration quenching were observed in Er3+ doped samples. The results obtained demonstrated the fundamental role of the phonon energy in the mechanism of fluorescence. The low phonon energy of chalcogenides decreased the rate of non-radiative processes promoting co-operative upconversion. This effect could be exploited to design new lasers and sensitizers for solar energy harvesters.

Faecal lactoferrin--a novel test to differentiate between the irritable and inflamed bowel?

BACKGROUND: Distinguishing between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) can be challenging. AIMS: To investigate the utility of faecal lactoferrin as a marker of inflammation in patients with IBD, IBS and controls. METHODS: Disease activity in IBD patients was assessed using the modified Harvey-Bradshaw Activity Index. Stool samples were analysed using an ELISA assay. RESULTS: We recruited 137 patients with IBS, 126 with ulcerative colitis (UC) and 104 with Crohn's disease (CD), and 98 healthy volunteers. The median +/- IQ lactoferrin concentration (microg/g faecal weight) was 0 +/- 1.4 for IBS patients, 6.6 +/- 42 for UC patients, 4 +/- 12.7 for CD patients and 0.5 +/- 2 for healthy controls. Lactoferrin levels were significantly higher in IBD patients compared with IBS/healthy controls (P < 0.001). The median lactoferrin concentrations were significantly higher in active UC & CD patients compared with inactive patients (P < 0.001 and P = 0.002 respectively). The sensitivity, specificity, positive and negative predictive values of lactoferrin in distinguishing active IBD from IBS/healthy controls were 67% and 96%, 87% and 86.8% respectively. CONCLUSIONS: Lactoferrin is useful to differentiate between IBD and IBS, and can be used as an adjunct to blood parameters to determine IBD patients who have ongoing inflammation.

A simple model for circadian timing by mammals.

Circadian timing is structured in such a way as to receive information from the external and internal environments, and its function is the timing organization of the physiological and behavioral processes in a circadian pattern. In mammals, the circadian timing system consists of a group of structures, which includes the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the pineal gland. Neuron groups working as a biological pacemaker are found in the SCN, forming a biological master clock. We present here a simple model for the circadian timing system of mammals, which is able to reproduce two fundamental characteristics of biological rhythms: the endogenous generation of pulses and synchronization with the light-dark cycle. In this model, the biological pacemaker of the SCN was modeled as a set of 1000 homogeneously distributed coupled oscillators with long-range coupling forming a spherical lattice. The characteristics of the oscillator set were defined taking into account the Kuramoto's oscillator dynamics, but we used a new method for estimating the equilibrium order parameter. Simultaneous activities of the excitatory and inhibitory synapses on the elements of the circadian timing circuit at each instant were modeled by specific equations for synaptic events. All simulation programs were written in Fortran 77, compiled and run on PC DOS computers. Our model exhibited responses in agreement with physiological patterns. The values of output frequency of the oscillator system (maximal value of 3.9 Hz) were of the order of magnitude of the firing frequencies recorded in suprachiasmatic neurons of rodents in vivo and in vitro (from 1.8 to 5.4 Hz).

A simple model for circadian timing by mammals

Circadian timing is structured in such a way as to receive information from the external and internal environments, and its function is the timing organization of the physiological and behavioral processes in a circadian pattern. In mammals, the circadian timing system consists of a group of structures, which includes the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the pineal gland. Neuron groups working as a biological pacemaker are found in the SCN, forming a biological master clock. We present here a simple model for the circadian timing system of mammals, which is able to reproduce two fundamental characteristics of biological rhythms: the endogenous generation of pulses and synchronization with the light-dark cycle. In this model, the biological pacemaker of the SCN was modeled as a set of 1000 homogeneously distributed coupled oscillators with long-range coupling forming a spherical lattice. The characteristics of the oscillator set were defined taking into account the Kuramoto's oscillator dynamics, but we used a new method for estimating the equilibrium order parameter. Simultaneous activities of the excitatory and inhibitory synapses on the elements of the circadian timing circuit at each instant were modeled by specific equations for synaptic events. All simulation programs were written in Fortran 77, compiled and run on PC DOS computers. Our model exhibited responses in agreement with physiological patterns. The values of output frequency of the oscillator system (maximal value of 3.9 Hz) were of the order of magnitude of the firing frequencies recorded in suprachiasmatic neurons of rodents in vivo and in vitro (from 1.8 to 5.4 Hz).

Adapting a measure of acculturation for cross-cultural research.

Although Filipino Americans are projected to become the largest Asian American ethnic group in this millennium, no acculturation measure existed for this group. This article describes a systematic and replicable process used in adapting and modifying A Short Acculturation Scale for Hispanics (ASASH) for use with Filipino Americans. It depicts the multiple and iterative steps of translation and backtranslation to produce A Short Acculturation Scale for Filipino Americans (ASASFA) in English and in Tagalog--the Philippine national language. Also, it describes the methods undertaken for the measures to achieve linguistic and cross-cultural validity through content, technical, experiential, semantic, and conceptual equivalence. With the dearth of linguistically and culturally valid measures for immigrant populations, the adaptation of valid measures developed for other cultures remains a viable option.

Clinical decision-making styles of home healthcare nurses.

Using grounded theory method, this study of 21 home health nurses describes three clinical decision-making styles: skimming, surveying, and sleuthing. Experienced home health care nurses switch from one style to another when managing varying patient care situations. This study provides a broad view of clinical decision-making by integrating the context of nursing practice with the patients' clinical status, nurse-patient interaction, and nurses' knowledge and experience.