11 research outputs found
An ESR Spin Probe Study of the Interaction between Poly(ethylene oxide) and Dodecyl Sulfate Surfactants with Different Monovalent Metal Counterions
The Hydrophobic Effect in the Adsorption Process of Alkyltrimethylammonium Bromides on to Activated Carbon
This paper describes the hydrophobic effect in the process of adsorption of alkyltrimethylammonium bromides from aqueous solution on to an activated carbon surface. Measurements of the adsorption isotherms of a series of alkyltrimethylammonium bromides with different hydrocarbon tail lengths at the activated carbon surface were carried out. In order to investigate the temperature dependence of the adsorption process, the determination of the adsorption of cetyltrimethylammonium bromide (CTAB) was undertaken at different temperatures in the range 20â60°C. From the experimental results obtained, the relevant thermodynamic quantities have been calculated. The role played by the hydrophobic effect in the adsorption process of cationic surfactants on to activated carbon and the factors affecting the adsorption mechanism were discussed
Interactions between Sodium Dodecyl Sulfate and Hydrophobically Modified Poly(acrylamide)s Studied by Electron Spin Resonance and Transmission Electron Microscopy
Interaction between Poly(ethylene oxide) and Dodecyl Sulfates with Different Monovalent Metal Counterions Studied by Microcalorimetry
Dilational Properties of Novel Amphiphilic Dendrimers at WaterâAir and WaterâHeptane Interfaces
In this work, a series of novel amphiphilic dendrimers
taking polyamidoamine
dendrimer as the core with different hydrophobic tails QPAMC<sub>m</sub> were synthesized and the dilational properties were studied as monolayers
by dilational rheological measurements at the waterâair and
waterâ<i>n</i>-heptane interfaces to explore the
nature of adsorption behaviors. The results showed that the maximum
values of the dilational modulus seemed to have no obvious variation
in a wide change of hydrophobic chain length at the surface. However,
there was considerable variability in the tendency of the influence
of bulk concentration on the dilational modulus at the two different
interfaces. It was interestingly found that the diffusion-exchange
process slowed down with the increase of alkyl chain length leading
to more elastic nature of adsorption film, which was contrary to the
tendencies of conventional single chain and gemini surfactants. It
is reasonable to consider that, in the case of the molecule having
short chain length such as QPAMC<sub>8</sub>, the alkyl chains are
too short to overlap across the headgroup, enable the intermolecular
hydrophobic interaction to be predominant with increasing of surface
concentration, which enhances the elasticity and shows the slowest
diffusion-exchange process. Whereas, when the chain length increases
to 12 or 16, the alkyl chains are long enough to act intramolecularly
to form intracohesion conformation, which results in enhancing the
diffusion-exchange process. In conclusion, the interfacial behaviors
are dictated by the size ratio between the tail and headgroup. A reasonable
model with respect to the molecular interaction was proposed on the
basis of experimental data. The results of interfacial tension relaxation
and dynamic light scattering (DLS) experiments, in accord with the
proposed mechanism, also present the unusual tendency comparing to
the traditional single or gemini surfactants
Association of immune checkpoint inhibitors therapy with arterial thromboembolic events in cancer patients: A retrospective cohort study
Abstract Background Immune checkpoint inhibitors (ICIs) have emerged as a standard treatment for various malignancies. However, research indicates blocking the immune checkpoint pathway may exacerbate atherosclerotic lesions. Objectives We aimed to investigate whether ICI therapy increases the risk of arterial thromboembolic events (ATEs). Methods A retrospective cohort study was conducted on patients with histologically confirmed cancer at our institution between 2018 and 2021, using the propensity score matching method. The primary endpoint was ATEs occurrence, comprising acute coronary syndrome, stroke/transient ischemic attack, and peripheral arterial thromboembolism. Subgroup analyses assessed whether the ICI treatment effect on ATEs varied over time by limiting the maximum followâup duration. Logistic regression analysis identified ATE risk factors in ICIâtreated patients. Results Overall, the ICI group (nâ=â2877) demonstrated an ATEs risk 2.01 times higher than the nonâICI group (RR, 2.01 [95% CI (1.61â2.51)]; pâ<â0.001). Subgroup analysis revealed no significant increase in ATEs risk for ICIâtreated patients within 1âyear (Limited to a max 9âmonth followâup, pâ=â0.075). However, ATEs risk in the ICI group rose by 41% at 1âyear (pâ=â0.010) and 97% at 4âyears (pââ€â0.001). Age, diabetes, hypertension, peripheral atherosclerosis, atrial fibrillation, chronic ischemic heart disease, distant cancer metastasis, and ICI treatment cycles contributed to ATEs risk elevation in ICIâtreated patients. Conclusion ICIâtreated patients may exhibit a higher risk of ATEs, especially after 1âyear of treatment
Phase equilibria of supercritical C02-ethanol-stearic acid ternary system and hydrogen bonding between ethanol and stearic acid
Structure-Function Analysis of PrsA Reveals Roles for the Parvulin-like and Flanking N- and C-terminal Domains in Protein Folding and Secretion in Bacillus subtilis
Deficiency of Asparagine Synthetase Causes Congenital Microcephaly and a Progressive Form of Encephalopathy
International audienceWe analyzed four families that presented with a similar condition characterized by congenital micro-cephaly, intellectual disability, progressive cerebral atrophy, and intractable seizures. We show that recessive mutations in the ASNS gene are responsible for this syndrome. Two of the identified missense mutations dramatically reduce ASNS protein abundance, suggesting that the mutations cause loss of function. Hypomorphic Asns mutant mice have structural brain abnormalities, including enlarged ventricles and reduced cortical thickness, and show deficits in learning and memory mimicking aspects of the patient phenotype. ASNS encodes asparagine synthetase, which catalyzes the synthesis of asparagine from glutamine and aspartate. The neurological impairment resulting from ASNS deficiency may be explained by asparagine depletion in the brain or by accumulation of aspartate/gluta-mate leading to enhanced excitability and neuronal damage. Our study thus indicates that asparagine synthesis is essential for the development and function of the brain but not for that of other organs