390 research outputs found
Theory and simulations of rigid polyelectrolytes
We present theoretical and numerical studies on stiff, linear
polyelectrolytes within the framework of the cell model. We first review
analytical results obtained on a mean-field Poisson-Boltzmann level, and then
use molecular dynamics simulations to show, under which circumstances these
fail quantitatively and qualitatively. For the hexagonally packed nematic phase
of the polyelectrolytes we compute the osmotic coefficient as a function of
density. In the presence of multivalent counterions it can become negative,
leading to effective attractions. We show that this results from a reduced
contribution of the virial part to the pressure. We compute the osmotic
coefficient and ionic distribution functions from Poisson-Boltzmann theory with
and without a recently proposed correlation correction, and also simulation
results for the case of poly(para-phenylene) and compare it to recently
obtained experimental data on this stiff polyelectrolyte. We also investigate
ion-ion correlations in the strong coupling regime, and compare them to
predictions of the recently advocated Wigner crystal theories.Comment: 32 pages, 15 figures, proceedings of the ASTATPHYS-MEX-2001, to be
published in Mol. Phy
Taxation of real estate: Russian reforms and foreign practice
In this report, a comparative analysis of Russian reforms in the field of real estate taxation is conducted and foreign practice investigated
Third-hand smoking: indoor measurements of concentration and sizes of cigarette smoke particles after resuspension
International audienc
Outcome of Colonic Surgery in Elderly Patients with Colon Cancer
Introduction. Colonic cancer is one of the most
commonly diagnosed malignancies and most often occurs in patients
aged 65 years or older. Aim. To evaluate the
outcome of colonic surgery in the elderly in our hospital and to
compare five-year survival rates between the younger and elderly
patients. Methods. 207 consecutive patients
underwent surgery for colon cancer. Patients were separated in
patients younger than 75 and older than 75 years.
Results. Elderly patients presented significantly
more (P < .05) as a surgical emergency, had a longer duration of
admission and were more often admitted to the ICU (P < .01). Also, elderly patients had significant more
co-morbidities, especially cardiovascular pathology (P < .01). Post-operative complications were seen more often in
the elderly, although no significant difference was seen in
anastomotic leakage. The five-year survival rate in the younger
group was 62% compared with 36% in the elderly (P < .05). DFS was 61% in the younger patients compared
with 32% in the elderly (P < .05). Conclusion. Curative resection of
colonic carcinoma in the elderly is well tolerated and age alone
should not be an indication for less aggressive therapy. However,
the type and number of co-morbidities influence post-operative
mortality and morbidity
Characterization of the Soluble Nanoparticles Formed through Coulombic Interaction of Bovine Serum Albumin with Anionic Graft Copolymers at Low pH
A static light scattering (SLS) study of bovine serum albumin (BSA) mixtures
with two anionic graft copolymers of poly (sodium acrylate-co-sodium
2-acrylamido-2-methyl-1-propanesulphonate)-graft-poly (N,
N-dimethylacrylamide), with a high composition in poly (N,
N-dimethylacrylamide) (PDMAM) side chains, revealed the formation of oppositely
charged complexes, at pH lower than 4.9, the isoelectric point of BSA. The
core-corona nanoparticles formed at pH = 3.00, were characterized. Their
molecular weight and radius of gyration were determined by SLS, while their
hydrodynamic radius was determined by dynamic light scattering. Small angle
neutron scattering measurements were used to determine the radius of the
insoluble complexes, comprising the core of the particles. The values obtained
indicated that their size and aggregation number of the nanoparticles, were
smaller when the content of the graft copolymers in neutral PDMAM side chains
was higher. Such particles should be interesting drug delivery candidates, if
the gastrointestinal tract was to be used
Randomised, placebo-controlled, double-blind, double-dummy, multicentre trial comparing electronic cigarettes with nicotine to varenicline and to electronic cigarettes without nicotine: the ECSMOKE trial protocol.
Electronic cigarettes (EC) mainly with nicotine content are widely used worldwide. Although the number of publications about its use is increasing exponentially, evidence-based, unbiased, conclusive, head-to-head comparisons about its efficacy and safety as an aid for smoking cessation are lacking. METHODS AND ANALYSIS: Design: randomised, placebo and reference treatment-controlled, multicentre, double-blind, double-dummy, parallel-group trial. Participants: smokers smoking at least 10 cigarettes/day in the past year and motivated to quit, aged 18-70 years. Interventions: (A) EC without nicotine (ECwoN) plus placebo tablets of varenicline administered by oral route: placebo condition, (B) EC with nicotine (ECwN) plus placebo tablets of varenicline: ECwN condition. Voltage regulated EC will be used with liquid containing 12 mg/mL of nicotine for ad libitum use. Flavour: blond tobacco. (C) Reference: ECwoN plus 0.5 mg varenicline tablets: varenicline condition. Varenicline administered according to the marketing authorisationauthorisation. Treatment duration: 1 week+3 months. Primary outcome: continuous smoking abstinence rate (CAR) (abstinence from conventional/combustible cigarettes) during the last 4 weeks (weeks 9-12) of the treatment period defined as self-report of no smoking during the previous 2 weeks and expired air carbon monoxide ≤8 at visit 4 at week 10 after target quit date (TQD), that is, 11 weeks after treatment initiation AND at visit 5, week 12 after TQD, that is, 13 weeks after treatment initiation. Secondary outcomes: safety profile; point prevalence abstinence rate; CAR confirmed by urinary anabasine concentration; changes in cigarettes/day consumption; craving for tobacco and withdrawal symptoms with respect of baseline.
The ethics committee approval was obtained on 17 April 2018. All data collected about the study participants will be anonymised. Investigators will communicate trial results to participants, health authorities, healthcare professionals, the public and other relevant groups without any publication restrictions.
NCT03630614; Pre-results
Counterion adsorption on flexible polyelectrolytes: comparison of theories
Counterion adsorption on a flexible polyelectrolyte chain in a spherical
cavity is considered by taking a "permuted" charge distribution on the chain so
that the "adsorbed" counterions are allowed to move along the backbone. We
compute the degree of ionization by using self-consistent field theory (SCFT)
and compare with the previously developed variational theory. Analysis of
various contributions to the free energy in both theories reveals that the
equilibrium degree of ionization is attained mainly as an interplay of the
adsorption energy of counterions on the backbone, the translational entropy of
the small ions, and their correlated density fluctuations. Degree of ionization
computed from SCFT is significantly lower than that from the variational
formalism. The difference is entirely due to the density fluctuations of the
small ions in the system, which are accounted for in the variational procedure.
When these fluctuations are deliberately suppressed in the truncated
variational procedure, there emerges a remarkable quantitative agreement in the
various contributing factors to the equilibrium degree of ionization, in spite
of the fundamental differences in the approximations and computational
procedures used in these two schemes. Nevertheless, since the significant
effects from density fluctuations of small ions are not captured by the SCFT,
and due to the close agreement between SCFT and the other contributing factors
in the more transparent variational procedure, the latter is a better
computational tool for obtaining the degree of ionization
The Accuracy of Clinical Staging of Stage I-IIIa Non-Small Cell Lung Cancer : An Analysis Based on Individual Participant Data
BACKGROUND: Clinical staging of non-small cell lung cancer (NSCLC) helps determine the prognosis and treatment of patients; few data exist on the accuracy of clinical staging and the impact on treatment and survival of patients. We assessed whether participant or trial characteristics were associated with clinical staging accuracy as well as impact on survival. METHODS: We used individual participant data from randomized controlled trials (RCTs), supplied for a meta-analysis of preoperative chemotherapy (+/- radiotherapy) vs surgery alone (+/- radiotherapy) in NSCLC. We assessed agreement between clinical TNM (cTNM) stage at randomization and pathologic TNM (pTNM) stage, for participants in the control group. RESULT: Results are based on 698 patients who received surgery alone (+/- radiotherapy) with data for cTNM and pTNM stage. Forty-six percent of cases were cTNM stage I, 23% were cTNM stage II, and 31% were cTNM stage IIIa. cTNM stage disagreed with pTNM stage in 48% of cases, with 34% clinically understaged and 14% clinically overstaged. Agreement was not associated with age (P = .12), sex (P = .62), histology (P = .82), staging method (P = .32), or year of randomization (P = .98). Poorer survival in understaged patients was explained by the underlying pTNM stage. Clinical staging failed to detect T4 disease in 10% of cases and misclassified nodal disease in 38%. CONCLUSION: This study demonstrates suboptimal agreement between clinical and pathologic staging. Discrepancies between clinical and pathologic T and N staging could have led to different treatment decisions in 10% and 38% of cases, respectively. There is therefore a need for further research into improving staging accuracy for patients with stage I-IIIa NSCLC.Peer reviewe
Hyperpolypharmacy is a predictor of mortality after left ventricular assist device (LVAD) implantation
Background: The prevalence of (hyper)polypharmacy in patients on left ventricular assist device (LVAD) support and its effect on clinical outcomeis unknown. Therefore, we aimed to determine the prevalence of (hyper)polypharmacy in LVAD patients and evaluate its association with mortality and complications. Materials and methods: 210 patients aged ≥40 years who received a primary LVAD implantation between 2011 and 2019 were included for analysis. Polypharmacy and hyperpolypharmacy were defined as the concomitant use of 5–9 and ≥10 medications at discharge after LVAD implantation, respectively. Cause specific cox regression was used to assess the association of ≥10 medications with mortality, cardiac arrhythmia, driveline infection and major bleeding. Results: The median age of the patients was 57.5 years, and 35.7 % were female. The average number of discharge medications was 8.8 ± 2.3 per patient. The prevalence of patients with 5–9 medications and ≥10 medications was 62.9 % and 34.8 %, respectively. The median follow-up duration was 948 days (interquartile range 874 days). The prescription of ≥10 medications was significantly associated with a higher risk of mortality (HR 2.03; 95 % CI 1.15–3.6, p-value 0.02) adjusted for sex, age, comorbidity and stratified for device type. The prescription of ≥10 medications was not associated with a higher risk of major bleeding, cardiac arrhythmia or driveline infection. Conclusions: (Hyper)polypharmacy is highly prevalent in LVAD patients and is independently associated with a higher risk of mortality. Future research is needed to assess the efficacy of individual risk-benefit profiling of (cardiovascular) medication to ensure appropriate polypharmacy and to decrease negative health outcomes
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