Daily activity during stability and exacerbation of chronic obstructive pulmonary disease

BACKGROUND: During most COPD exacerbations, patients continue to live in the community but there is little information on changes in activity during exacerbations due to the difficulties of obtaining recent, prospective baseline data. METHODS: Patients recorded on daily diary cards any worsening in respiratory symptoms, peak expiratory flow (PEF) and the number of steps taken per day measured with a Yamax Digi-walker pedometer. Exacerbations were defined by increased respiratory symptoms and the number of exacerbations experienced in the 12 months preceding the recording of daily step count used to divide patients into frequent (> = 2/year) or infrequent exacerbators. RESULTS: The 73 COPD patients (88% male) had a mean (+/-SD) age 71(+/-8) years and FEV1 53(+/-16)% predicted. They recorded pedometer data on a median 198 days (IQR 134-353). At exacerbation onset, symptom count rose by 1.9(+/-1.3) and PEF fell by 7(+/-13) l/min. Mean daily step count fell from 4154(+/-2586) steps/day during a preceding baseline week to 3673(+/-2258) step/day during the initial 7 days of exacerbation (p = 0.045). Patients with larger falls in activity at exacerbation took longer to recover to stable level (rho = -0.56; p < 0.001). Recovery in daily step count was faster (median 3.5 days) than for exacerbation symptoms (median 11 days; p < 0.001). Recovery in step count was also faster in untreated compared to treated exacerbation (p = 0.030).Daily step count fell faster over time in the 40 frequent exacerbators, by 708 steps/year, compared to 338 steps/year in 33 infrequent exacerbators (p = 0.002). CONCLUSIONS: COPD exacerbations reduced physical activity and frequent exacerbations accelerate decline in activity over time

Upper respiratory symptoms worsen over time and relate to clinical phenotype in COPD.

Copyright © 2015 by the American Thoracic Society.Rationale: How nasal symptoms in patients with chronic obstructive pulmonary disease (COPD) change over time and resolve during naturally occurring exacerbations has not been described previously. Objectives: To evaluate the evolution and impact of upper airway symptoms in a well-defined COPD cohort when stable and at exacerbation. Methods: Patients in the LondonCOPDcohortwere asked about the presence of nasal symptoms (nasal discharge, sneezing, postnasal drip, blocked nose, and anosmia) over an 8-year period (2005-2013) every 3 months at routine clinic visits while in a stable state and daily during exacerbations with the use of diary cards. Data were prospectively collected, and, in a subgroup of patients,COPDAssessment Test scores and human rhinovirus identification by polymerase chain reaction were available. Patients were also defined as having infrequent or frequent exacerbations (<2 or ≥2 exacerbations/yr, respectively). Measurements and Main Results: At an aggregate of 4,368 visits, 209 patients with COPD were asked about their nasal symptoms. At 2,033 visits when the patients were stable, the odds ratio (OR) for nasal discharge increased by 1.32% per year (95% confidence interval [CI], 1.19-1.45; P<0.001); the OR for sneezing increased by 1.16%(95%CI, 1.05-1.29;P = 0.005); theORfor postnasal drip increased by 1.18% (95% CI, 1.03-1.36; P=0.016); and theOR for anosmia increased by 1.19% (95% CI, 1.03-1.37; P = 0.015). At visits when the patients were having exacerbations, nasal discharge was present for 7 days and blocked nose, sneezing, and postnasal drip increased for just 3 days. Anosmia did not change. Nasal dischargewasmore likely inpatientswith frequent exacerbations (OR, 1.96; 95% CI, 1.17-3.28; P= 0.011), and COPD Assessment Test scores were higher by 1.06 units (95% CI, 0.32-1.80; P=0.005) when patients were stable and higher by 1.30 units (95% CI, 0.05-2.57; P= 0.042) during exacerbations. Conclusions: Upper airway symptoms increase over time in patients with COPD and are related to the frequent exacerbation phenotype. These longitudinal changes may be due to increasing airway inflammation or to progression of COPD

Inflammatory thresholds and the species-specific effects of colonising bacteria in stable chronic obstructive pulmonary disease

There has been increasing interest in the use of newer, culture-independent techniques to study the airway microbiome of COPD patients. We investigated the relationships between the three common potentially pathogenic microorganisms (PPMs) Haemophilus influenzae, Streptococcus pneumoniae and Moraxella catarrhalis, as detected by quantitative PCR (qPCR), and inflammation and health status in stable patients in the London COPD cohort

The origin of defects induced in ultra-pure germanium by Electron Beam Deposition

The creation of point defects in the crystal lattices of various semiconductors by subthreshold events has been reported on by a number of groups. These observations have been made in great detail using sensitive electrical techniques but there is still much that needs to be clarified. Experiments using Ge and Si were performed that demonstrate that energetic particles, the products of collisions in the electron beam, were responsible for the majority of electron-beam deposition (EBD) induced defects in a two-step energy transfer process. Lowering the number of collisions of these energetic particles with the semiconductor during metal deposition was accomplished using a combination of static shields and superior vacuum resulting in devices with defect concentrations lower than $10^{11}\,$cm$^{-3}$, the measurement limit of our deep level transient spectroscopy (DLTS) system. High energy electrons and photons that samples are typically exposed to were not influenced by the shields as most of these particles originate at the metal target thus eliminating these particles as possible damage causing agents. It remains unclear how packets of energy that can sometimes be as small of 2eV travel up to a $\mu$m into the material while still retaining enough energy, that is, in the order of 1eV, to cause changes in the crystal. The manipulation of this defect causing phenomenon may hold the key to developing defect free material for future applications.Comment: 18 pages, 9 figure

Yangian in the Twistor String

We study symmetries of the quantized open twistor string. In addition to global PSL(4|4) symmetry, we find non-local conserved currents. The associated non-local charges lead to Ward identities which show that these charges annihilate the string gluon tree amplitudes, and have the same form as symmetries of amplitudes in N=4 super conformal Yang Mills theory. We describe how states of the open twistor string form a realization of the PSL(4|4) Yangian superalgebra.Comment: 37 pages, 4 figure

Complex sequencing rules of birdsong can be explained by simple hidden Markov processes

Complex sequencing rules observed in birdsongs provide an opportunity to investigate the neural mechanism for generating complex sequential behaviors. To relate the findings from studying birdsongs to other sequential behaviors, it is crucial to characterize the statistical properties of the sequencing rules in birdsongs. However, the properties of the sequencing rules in birdsongs have not yet been fully addressed. In this study, we investigate the statistical propertiesof the complex birdsong of the Bengalese finch (Lonchura striata var. domestica). Based on manual-annotated syllable sequences, we first show that there are significant higher-order context dependencies in Bengalese finch songs, that is, which syllable appears next depends on more than one previous syllable. This property is shared with other complex sequential behaviors. We then analyze acoustic features of the song and show that higher-order context dependencies can be explained using first-order hidden state transition dynamics with redundant hidden states. This model corresponds to hidden Markov models (HMMs), well known statistical models with a large range of application for time series modeling. The song annotation with these models with first-order hidden state dynamics agreed well with manual annotation, the score was comparable to that of a second-order HMM, and surpassed the zeroth-order model (the Gaussian mixture model (GMM)), which does not use context information. Our results imply that the hierarchical representation with hidden state dynamics may underlie the neural implementation for generating complex sequences with higher-order dependencies

Approaches towards expression profiling the response to treatment

Over the past 8 years there has been a wealth of breast cancer gene expression studies. The majority of these studies have focused upon characterising a tumour at presentation, before treatment, rather than looking at the effects of treatment on the tumour. More recently, a number of groups have moved from predicting prognosis based upon long-term follow-up to alternative approaches of using expression profiling to measure the effect of treatment on breast tumours and potentially predict response to therapy using either post-treatment samples or both pre-treatment and post-treatment samples. Whilst this provides great potential to further our understanding of the mode of action of treatments and to more accurately select which patients will benefit from a particular treatment, serious issues of experimental design must be considered