Ytterbium doped nano-crystalline optical fiber for reduced photodarkening

We report suppression of photodarkening in Yb-doped nano-crystalline fibers in silica host. The photodarkening induced loss reduced by 20 times compared to Yb-doped aluminosilicate fibers. The laser efficiency of the nano-crystalline fiber was 79%

Optical fiber fabrication using novel gas-phase deposition technique

We report a highly versatile chemical-in-crucible preform fabrication technique suitable for gas-phase deposition of doped optical fibers. Aluminosilicate and ytterbium-doped phosphosilicate fibers are presented demonstrating the technique and its potential for realizing complex fiber designs that are suitable for the next generation of high-power fiber devices. The results show aluminum-doped fiber with numerical aperture of 0.28 and ytterbium-doped fiber with a measured slope efficiency of 84% with respect to pump launch power

Distinguishing regional from within-codon rate heterogeneity in DNA sequence alignments

We present an improved phylogenetic factorial hidden Markov model (FHMM) for detecting two types of mosaic structures in DNA sequence alignments, related to (1) recombination and (2) rate heterogeneity. The focus of the present work is on improving the modelling of the latter aspect. Earlier papers have modelled different degrees of rate heterogeneity with separate hidden states of the FHMM. This approach fails to appreciate the intrinsic difference between two types of rate heterogeneity: long-range regional effects, which are potentially related to differences in the selective pressure, and the short-term periodic patterns within the codons, which merely capture the signature of the genetic code. We propose an improved model that explicitly distinguishes between these two effects, and we assess its performance on a set of simulated DNA sequence alignments

Guanosine nucleotides regulate B2 kinin receptor affinity of agonists but not of antagonists: Discussion of a model proposing receptor precoupling to G protein

The effect of nucleotides on binding of the B2 kinin (BK) receptor agonist {[}H-3]BK and the antagonist {[}H-3]NPC17731 to particulate fractions of human foreskin fibroblasts was studied. At 0 degrees C, particulate fractions exhibited a single class of binding sites with a Kd of 2.3 nM for {[}H-3]BK and a K-d Of 3.8 nM for the antagonist {[}H-3]NPC17731. Incubation with radioligands at 37 degrees C for 5 min gave a reduction of agonist, as well as antagonist, binding that was between 0-40% depending on the preparation, even in the absence of guanosine nucleotides. As shown by Scatchard analysis, this reduction in specific binding was due to a shift in the affinity of at least a fraction of the receptors. The presence at 37 degrees C of the guanine nucleotides GTP, GDP and their poorly hydrolyzable analogs left {[}H-3]-NPC17731 binding unaffected, but reduced the receptor affinity for {[}H-3]BK to a K-d Of about 15 nM. The maximal number of receptors, however, was unchanged. This affinity change was strongly dependent on the presence of bivalent cations, in particular Mg2+. It was reversed by incubation at 0 degrees C, The rank order of the guanosine nucleotides for {[}H-3]BK binding reduction was GTP{[}gamma S] = Gpp{[}NH]p > GTP = GDP > GDP{[}beta S]. GMP, ATP, ADP and AMP showed no influence on agonist binding. A model for the interaction of the B2 kinin receptor with G proteins is discussed

Equivalent thermo-mechanical parameters for perfect crystals

Thermo-elastic behavior of perfect single crystal is considered. The crystal is represented as a set of interacting particles (atoms). The approach for determination of equivalent continuum values for the discrete system is proposed. Averaging of equations of particles' motion and long wave approximation are used in order to make link between the discrete system and equivalent continuum. Basic balance equations for equivalent continuum are derived from microscopic equations. Macroscopic values such as Piola and Cauchy stress tensors and heat flux are represented via microscopic parameters. Connection between the heat flux and temperature is discussed. Equation of state in Mie-Gruneisen form connecting Cauchy stress tensor with deformation gradient and thermal energy is obtained from microscopic considerations.Comment: To be published in proceedings of IUTAM Simposium on "Vibration Analysis of Structures with Uncertainties", 2009; 14 pages

A qualitative investigation into the follow-up support offered to patients after an NHS obesity weight management programme in Liverpool

The prevalence of obesity has been increasing in Liverpool over the last 20 years(1). In response a weight management programme was devised by Liverpool Community Health using existing related services. The service involves dietitians working towards facilitating dietary and lifestyle changes in local obese NHS patients via a 12 week education programme. Follow up support is highlighted in the literature as a required element for success in weight management, however there is a lack of existing qualitative research focussing on this area(2). This study investigated patients’ lived experiences of the programme; specifically regarding follow up support. Participants (n 16) were recruited from the programme to engage in a semi-structured focus group after their final education session with an emphasis on post-programme support. Data was audio-recorded, transcribed verbatim and analysed using constant comparison analysis. A coding frame was developed until saturation was reached. The table outlines themes which emerged from the data and future recommendations. Regardless of many positive comments, participants frequently complained about a lack of follow up support from the programme and from family and friends. Some explained how they were often insulted and belittled by those closest to them and were vehemently against involving these people in their weight management. Follow up weigh-in groups based around peer support were suggested, however these were also met with criticism as participants mentioned they would be unhappy to engage unless sessions were run by a dietitian or qualified health professional. Despite favourable remarks concerning the social elements of the programme and the acquisition of new skills and knowledge, many participants still felt unable to continue without suitable follow up support and excessive practitioner dependence, therefore deflecting accountability for their health away from themselves. The results show that for changes made during programme to be sustainable, patients need a robust, post-programme support network where they become responsible for their own actions and are encouraged to set and work towards their own goals. Proposed solutions to this are the introduction of online support programmes, follow up dietitian phone calls and weight management support inventories to assess the level of social support needed(3). Furthermore, NHS Community Food Workers have also been effective in offering individualised support for behaviour changes and may too be useful for assisting with follow up sessions(4)

Effects of interleukin-1β Inhibition on blood pressure, incident hypertension, and residual inflammatory risk

While hypertension and inflammation are physiologically inter-related, the effect of therapies that specifically target inflammation on blood pressure is uncertain. The recent CANTOS (Canakinumab Anti-inflammatory Thrombosis Outcomes Study) afforded the opportunity to test whether IL (interleukin)-1β inhibition would reduce blood pressure, prevent incident hypertension, and modify relationships between hypertension and cardiovascular events. CANTOS randomized 10 061 patients with prior myocardial infarction and hsCRP (high sensitivity C-reactive protein) ≥2 mg/L to canakinumab 50 mg, 150 mg, 300 mg, or placebo. A total of 9549 trial participants had blood pressure recordings during follow-up; of these, 80% had a preexisting diagnosis of hypertension. In patients without baseline hypertension, rates of incident hypertension were 23.4, 26.6, and 28.1 per 100-person years for the lowest to highest baseline tertiles of hsCRP (P>0.2). In all participants random allocation to canakinumab did not reduce blood pressure (P>0.2) or incident hypertension during the follow-up period (hazard ratio, 0.96 [0.85–1.08], P>0.2). IL-1β inhibition with canakinumab reduces major adverse cardiovascular event rates. These analyses suggest that the mechanisms underlying this benefit are not related to changes in blood pressure or incident hypertension

The influence of continuous subcutaneous insulin infusion therapy vs. multiple daily injections upon the diet of those with Type 1 diabetes: A food diary investigation

There exist a number of therapeutic options for the management of Type 1 diabetes (T1D). Multiple daily injections (MDI) are one such treatment and involve 4-5 daily subcutaneous injections of insulin. This frequently used approach is widely regarded as an effective method of controlling glycaemia; however, if a patient continues to suffer disabling episodes of hypoglycaemia, or if HbA1c remains above 8.5% continuous subcutaneous insulin infusion (CSII) may instead be recommended1. This therapy employs a small programmable pump device to facilitate the administration of insulin to the patient via a cannula. Various advantages of CSII have been documented compared to MDI, including improvements in glycaemic control and reduced incidence of both hypoglycaemia and the dawn phenomenon. An additional attribute, characterised by the flexible nature of the therapy, is that a liberalised diet may be enjoyed by patients, which in turn may infer potential nutrition and quality of life aberrations. This phenomenon is surprisingly under researched and further investigations to inform both treatment and risk would therefore be beneficial. Following ethical approval and informed consent patients with T1D using either CSII or MDI from the Royal Liverpool Hospital were asked to complete a 5 day weighed food diary. Dietplan 6 software was used to process the responses and demographic data from participants’ medical records were added to the dataset. All data were then interrogated using descriptive statistics and any non-normal data were transformed logarithmically before further enquiry with t-tests or analysed non-parametrically with Mann-Whitney-U-tests. The sample comprised of 20 patients (35% male, 65% female) with 11 using CSII and 9 using MDI. The patients’ mean age was 49±16 years and the majority were overweight or obese (72.7% CSII, 55.6% MDI). Nutrient Amount per day (CSII group) Amount per day (MDI group) % energy intake per day (CSII group) % energy intake per day (MDI group) Energy 1866.6 Kcal 2110.5 Kcal N/A N/A Protein 69.0 g/day 89.9 g/day 14.8 17.0 Total CHO 232.3 g/day 251.8 g/day 46.7 44.7 Total sugars 99.8 g/day 88.6 g/day 20.0 15.7 Total fat 73.5 g/day 80.1 g/day 35.4 34.2 Saturated fat 31.6 g/day 29.8 g/day 15.2 12.7 Table. Selected food diary results from patients using CSII and MDI compared to reference nutrient intakes. Results showed mean energy intake was below the reference nutrient intake (RNI) for the CSII group; potentially suggestive of underreporting (Table)3. Patients using both CSII and MDI consumed protein above the RNI; however, this macronutrient contributed towards 14.8% of the daily energy intake of patients using CSII and 17.0% of those using MDI3. Total carbohydrate (CHO) consumption was below the RNI of 50%; however, it should be noted that consumption of total sugars was above the RNI for males and females in both groups4. Previous research by the authors suggesting habitual fruit consumption, particularly in those using CSII, may explain this5. Total fat and saturated fat consumption was mostly synonymic with RNI’s. Although no statistically significant associations were seen between any of the variables and the diets of the two populations appeared largely homogenous it is reassuring that no detrimental changes occurred. Despite this further analysis of total energy, protein and CHO quality is warranted