On designing observers for time-delay systems with nonlinear disturbances

This is the post print version of the article. The official published version can be obtained from the link below - Copyright 2002 Taylor & Francis LtdIn this paper, the observer design problem is studied for a class of time-delay nonlinear systems. The system under consideration is subject to delayed state and non-linear disturbances. The time-delay is allowed to be time-varying, and the non-linearities are assumed to satisfy global Lipschitz conditions. The problem addressed is the design of state observers such that, for the admissible time-delay as well as non-linear disturbances, the dynamics of the observation error is globally exponentially stable. An effective algebraic matrix inequality approach is developed to solve the non-linear observer design problem. Specifically, some conditions for the existence of the desired observers are derived, and an explicit expression of desired observers is given in terms of some free parameters. A simulation example is included to illustrate the practical applicability of the proposed theory.The work of Z. Wang was supported in part by the University of Kaiserslautern of Germany and the Alexander von Humboldt Foundation of Germany

The Sloan Lens ACS Survey. VIII. The relation between environment and internal structure of early-type galaxies

We study the relation between the internal structure of early-type galaxies and their environment using 70 strong gravitational lenses from the Sloan ACS Lens Survey. The Sloan database is used to determine two measures of overdensity of galaxies around each lens: the projected number density of galaxies inside the tenth nearest neighbor (\Sigma_{10}) and within a cone of radius one h^{-1} Mpc (D_1). Our main results are: 1) The average overdensity is somewhat larger than unity, consistent with lenses preferring overdense environments as expected for massive early-type galaxies (12/70 lenses are in known groups/clusters). 2) The distribution of overdensities is indistinguishable from that of "twin" non-lens galaxies selected from SDSS to have the same redshift and stellar velocity dispersion \sigma_*. Thus, within our errors, lens galaxies are an unbiased population, and the SLACS results can be generalized to the overall population of early-type galaxies. 3) Typical contributions from external mass distribution are no more than a few per cent, reaching 10-20% (~0.05-0.10 external convergence) only in the most extreme overdensities. 4) No significant correlation between overdensity and slope of the mass density profile of the lens is found. 5) Satellite galaxies (those with a more luminous companion) have marginally steeper mass density profiles than central galaxies (those without). This result suggests that tidal stripping may affect the mass structure of early-type galaxies down to kpc scales probed by strong lensing, when they fall into larger structures [ABRIDGED].Comment: ApJ, in press; minor changes with respect to v

Perioperative supplementation with a fruit and vegetable juice powder concentrate and postsurgical morbidity: a double-blind, randomised, placebo controlled clinical trial

Aims Surgical trauma leads to an inflammatory response that causes surgical morbidity. Reduced antioxidant micronutrient (AM)a levels and/or excessive levels of Reactive Oxygen Species (ROS)b have previously been linked to delayed wound healing and presence of chronic wounds. We aimed to evaluate the effect of pre-operative supplementation with encapsulated fruit and vegetable juice powder concentrate (JuicePlus+®) on postoperative morbidity and Quality of Life (QoL)c. Methods We conducted a randomised, double-blind, placebo-controlled two-arm parallel clinical trial evaluating postoperative morbidity following lower third molar surgery. Patients aged between 18 and 65 years were randomised to take verum or placebo for 10 weeks prior to surgery and during the first postoperative week. The primary endpoint was the between-group difference in QoL over the first postoperative week, with secondary endpoints being related to other measures of postoperative morbidity (pain and trismus). Results One-hundred and eighty-three out of 238 randomised patients received surgery (Intention-To-Treat population). Postoperative QoL tended to be higher in the active compared to the placebo group (p=0.059). Furthermore, reduction in mouth opening 2 days after surgery was 3.1 mm smaller (p=0.042), the mean pain score over the postoperative week was 9.4 mm lower (p=0.007) and patients were less likely to experience moderate to severe pain on postoperative day 2 (RR 0.58, p=0.030), comparing verum to placebo groups. Conclusion Pre-operative supplementation with a fruit and vegetable supplement rich in AM may improve postoperative QoL and reduce surgical morbidity and post-operative complications after surgery

Hydrogen atom in a spherical well: linear approximation

We discuss the boundary effects on a quantum system by examining the problem of a hydrogen atom in a spherical well. By using an approximation method which is linear in energy we calculate the boundary corrections to the ground-state energy and wave function. We obtain the asymptotic dependence of the ground-state energy on the radius of the well.Comment: Revised version to appear in European Journal of Physic

Submucosal diclofenac for acute postoperative pain in third molar surgery: A randomized, controlled clinical trial

Diclofenac sodium is a widely used nonsteroidal anti-inflammatory drug (NSAID) for relief of inflammatory pain. A recent formulation combines this drug with hydroxypropyl-β-cyclodextrin (HPβCD) to improve its solubility and to enable subcutaneous administration. Previous studies confirmed the efficacy of this combination. This study’s aim was to evaluate the efficacy, safety, and local tolerability of diclofenac HPβCD administered as a local submucosal injection prior to lower third molar surgery. We conducted a prospective, randomized, double-blind, placebo-controlled, parallel-group phase II single-center study. Seventy-five patients requiring mandibular third molar surgery were randomized into 1 of 5 groups: 5 mg/1 mL diclofenac HPβCD, 12.5 mg/1 mL diclofenac HPβCD, 25 mg/1 mL diclofenac HPβCD, 50 mg/1 mL diclofenac HPβCD, or 1 mL placebo. The respective study drug was injected into the mucosal tissue surrounding the surgical site prior to surgery following achievement of local anesthesia. The primary outcome measure was the area under the curve (AUC) of cumulative pain scores from end of surgery to 6 h postsurgery. This demonstrated a global treatment effect between the active groups and placebo, hence confirming the study drug’s efficacy (P = 0.0126). Secondary outcome measures included the time until onset of pain and the time until patients required rescue medication, both showing statistical significance of the study drug compared to placebo (P < 0.0161 and P < 0.0001, respectively). The time until rescue medication ranged between 7.8 h (for 25 mg/1 mL diclofenac HPβCD) and 16 h (for 50 mg/1 mL diclofenac HPβCD). Interestingly, the 5-mg/1-mL solution appeared superior to the 12.5-mg/1-mL and 25-mg/1-mL solutions (time until rescue medication = 12.44 h). A total of 14% of patients experienced minor adverse drug reactions (ADRs), of which 2 cases demonstrated flap necrosis. These resolved without further intervention. The study results overall indicate efficacy, safety, and relative tolerability of diclofenac HPβCD used locally as a submucosal injection prior to third molar surgery (ClinicalTrials.gov NCT01706588)

Determination of total and available fractions of PAHs by SPME in oily wastewaters : overcoming interference from NAPL and NOM

Background, aim, and scope Polycyclic aromatic hydrocarbons (PAHs) are often found in oily wastewaters. Their presence is usually the result of human activities and has a negative effect on the environment. One important step in addressing this problem is to evaluate the effectiveness of PAH removal by biological processes since these are the most cost-effective treatments known today. Many techniques are presently available for PAH determination in wastewaters. Solid phase microextracion (SPME) is known to be one of the most effective techniques for this purpose. When analyzing complex matrices with substances such as natural organic matter (NOM) and non-aqueous phase liquids (NAPL), it is important to differentiate the free dissolved PAH from matrix-bonded PAH. PAHs associated with the bonded fraction are less susceptible to biological treatment. The present study concerns the development of a simple and suitable methodology for the determination of the freely dissolved and the total fraction of PAHs present in oily wastewaters. The methodology was then applied to an oily wastewater from a fuel station retention basin. Material and methods Headspace SPME was used for analyzing PAH since the presence of a complex or dirty matrix in direct contact with the fiber may damage it. Four model PAHs—anthracene, fluorene, phenanthrene, and pyrene—were analyzed by GC-MS. Negligible depletion SPME technique was used to determine the free fraction. Total PAH was determined by enhancing the mass transfer from the bonded phase to the freely dissolved phase by temperature optimization and the use of the method of standard additions. The PAH absorption kinetics were determined in order to define the optimal sampling conditions for this method. The fitting of the experimental data to a mathematical model was accomplished using Berkeley Madonna software. Humic acid and silicon oil were used as model NOM and NAPL, respectively, to study the effect of these compounds on the decrease of SPME response. Then, the method was evaluated with wastewater from a fuel station spill retention basin. Results The SPME kinetic parameters—k 1 (uptake rate), k 2 (desorption rate), and K SPME (partition coefficient)—were determined from experimental data modeling. The determination of the free fraction required 15-min sampling to ensure that PAH depletion from sample was below 1%. For total PAH, a 30-min extraction at 100°C ensured the maximum signal response in the GC-MS. For the determination of free and total PAHs, extractions were performed before reaching the SPME equilibrium. The wastewater used in this study had no free fraction of the analyzed PAHs. However, the four studied PAHs were found when the method for total PAH was used. Discussion The addition of NOM and NAPL dramatically decreased the efficiency of the SPME. This decrease was the result of a greater partition of the PAHs to the NAPL and NOM phases. This fact was also observed in the analysis of the fuel station spill retention basin, where no free PAH was measured. However, using the method of standard addition for the determination of total PAH, it was possible to quantify all four PAHs. Conclusions The method developed in the present study was found to be adequate to differentiate between free and total PAH present in oily wastewater. It was determined that the presence of NOM and NAPL had a negative effect on SPME efficiency. Recommendations and perspectives The presence of binding substances had a great influence on SPME kinetics. Therefore, it is of extreme importance to determine their degree of interference when analyzing oily wastewaters or results can otherwise be erroneous. Other factors influencing the total PAH determinations should be considered in further studies.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/ 18816/2004, POCI/AMB/61044/200

Direct peptide bioconjugation/PEGylation at tyrosine with linear and branched polymeric diazonium salts

Direct polymer conjugation at peptide tyrosine residues is described. In this study Tyr residues of both leucine enkephalin and salmon calcitonin (sCT) were targeted using appropriate diazonium salt-terminated linear monomethoxy poly(ethylene glycol)s (mPEGs) and poly(mPEG) methacrylate prepared by atom transfer radical polymerization. Judicious choice of the reaction conditions-pH, stoichiometry, and chemical structure of diazonium salt-led to a high degree of site-specificity in the conjugation reaction, even in the presence of competitive peptide amino acid targets such as histidine, lysines, and N-terminal amine. In vitro studies showed that conjugation of mPEG 2000 to sCT did not affect the peptide's ability to increase intracellular cAMP induced in T47D human breast cancer cells bearing sCT receptors. Preliminary in vivo investigation showed preserved ability to reduce [Ca 2+] plasma levels by mPEG 2000-sCT conjugate in rat animal models. © 2012 American Chemical Society

Collaboration in the management of psoriasis and psoriatic arthritis: A survey of joint working in UK clinical practice

Background Treatment guidelines for psoriasis and psoriatic arthritis consider all skin and joint domains and recommend collaborative multidisciplinary team (MDT) working. The uptake of joint working in clinical practice for psoriatic disease management has not been well studied. Objectives This United Kingdom (UK) study aimed to provide a better understanding of current working patterns and collaborating specialities, as well as benefits and challenges of combined clinics. Methods An online survey was emailed to dermatology and rheumatology healthcare professionals (HCPs) using professional networks. Results Responses were received between October 2020 and April 2021 (N = 80); 60.0% of respondents worked in dermatology and 40.0% in rheumatology. Use of combined clinics with dermatology was reported by 40.6% of rheumatology HCPs, including joint (25.0%), parallel (3.1%) and virtual clinics (6.3%), and MDT meetings (6.2%). Similarly, 50.1% of dermatology HCPs reported use of joint (25.0%), parallel (4.2%) and virtual clinics (2.1%), single visits (2.1%), and MDT meetings (16.7%) with rheumatology. Around one-quarter of respondents collaborated via email, which was also the main method of collaboration with other specialists. Overall, one-quarter of respondents reported no collaboration in psoriatic disease management. Perceived benefits of combined clinics included shared knowledge, improved patient outcomes and increased patient satisfaction. Challenges included difficulties in aligning clinician time and geographical location, as well as limited ‘buy-in’ from senior management. Most respondents felt that the COVID-19 pandemic had partially or significantly impacted combined clinics. Conclusions This study is one of the first to survey collaborative working in psoriatic disease management and the first in the UK. These findings demonstrate the variety of approaches used and a lack of collaborative working by one-quarter of respondents. Despite the benefits, numerous challenges in establishing formal arrangements exist. More evidence is needed to demonstrate improved patient outcomes with collaborative working and to standardise best practice

Using Cognitive Pre-Testing Methods in the Development of a New Evidenced-Based Pressure Ulcer Risk Assessment Instrument

Background: Variation in development methods of Pressure Ulcer Risk Assessment Instruments has led to inconsistent inclusion of risk factors and concerns about content validity. A new evidenced-based Risk Assessment Instrument, the Pressure Ulcer Risk Primary Or Secondary Evaluation Tool - PURPOSE-T was developed as part of a National Institute for Health Research (NIHR) funded Pressure Ulcer Research Programme (PURPOSE: RP-PG-0407-10056). This paper reports the pre-test phase to assess and improve PURPOSE-T acceptability, usability and confirm content validity. Methods: A descriptive study incorporating cognitive pre-testing methods and integration of service user views was undertaken over 3 cycles comprising PURPOSE-T training, a focus group and one-to-one think-aloud interviews. Clinical nurses from 2 acute and 2 community NHS Trusts, were grouped according to job role. Focus group participants used 3 vignettes to complete PURPOSE-T assessments and then participated in the focus group. Think-aloud participants were interviewed during their completion of PURPOSE-T. After each pre-test cycle analysis was undertaken and adjustment/improvements made to PURPOSE-T in an iterative process. This incorporated the use of descriptive statistics for data completeness and decision rule compliance and directed content analysis for interview and focus group data. Data were collected April 2012-June 2012. Results: Thirty-four nurses participated in 3 pre-test cycles. Data from 3 focus groups, 12 think-aloud interviews incorporating 101 PURPOSE-T assessments led to changes to improve instrument content and design, flow and format, decision support and item-specific wording. Acceptability and usability were demonstrated by improved data completion and appropriate risk pathway allocation. The pre-test also confirmed content validity with clinical nurses. Conclusions: The pre-test was an important step in the development of the preliminary PURPOSE-T and the methods used may have wider instrument development application. PURPOSE-T proposes a new approach to pressure ulcer risk assessment, incorporating a screening stage, the inclusion of skin status to distinguish between those who require primary prevention and those who require secondary prevention/treatment and the use of colour to support pathway allocation and decision making. Further clinical evaluation is planned to assess the reliability and validity of PURPOSE-T and it’s impact on care processes and patient outcomes

Response Types and Factors Associated with Response Types to Biologic Therapies in Patients with Moderate-to-Severe Plaque Psoriasis from Two Randomized Clinical Trials.

This study aimed to understand treatment response dynamics, including factors associated with favorable response, among patients with moderate-to-severe psoriasis who received guselkumab, adalimumab, or secukinumab. These post hoc analyses used data from the phase III clinical trials ECLIPSE and VOYAGE 1, which were conducted between September 2021 and November 2022. On the basis of absolute Psoriasis Area and Severity Index (aPASI) scores, patients were divided into short-term response types (SRT1-6, based on week 20-48 response) and long-term response types (LRT1-4, based on week 52-252 response). Response types (RTs) were based on aPASI cutoffs deemed clinically relevant by the investigators; SRT1/LRT1 were the most favorable response types. Baseline characteristics were compared across RTs, and logistic regression analyses established factors associated with SRT1/LRT1. Overall, 1045, 662, and 272 patients were included in the ECLIPSE short-term, VOYAGE 1 short-term, and VOYAGE 1 long-term analyses, respectively. Mean age, body mass index (BMI), baseline aPASI score, and body surface area were lower in SRT1 than SRT6. In VOYAGE 1, adalimumab treatment, high BMI, and current/former smoking status resulted in less favorable responses. In the VOYAGE 1 long-term analysis, patients in LRT4 had the highest baseline aPASI score, were older, and were more often obese compared with other LRT groups. Regression analyses showed that SRT1 (both treatments) in VOYAGE 1 and ECLIPSE, and LRT1 (guselkumab group) in the VOYAGE 1 long-term analysis, were associated with week 16 aPASI response. In VOYAGE 1, SRT1 was associated with psoriasis duration and smoking status. Early treatment response and baseline characteristics, including smoking, psoriasis duration, and obesity, may be associated with longer-term response to biologics. ECLIPSE: NCT03090100, VOYAGE 1: NCT02207231