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 20–60°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

Dilational Properties of Novel Amphiphilic Dendrimers at Water–Air and Water–Heptane Interfaces

In this work, a series of novel amphiphilic dendrimers taking polyamidoamine dendrimer as the core with different hydrophobic tails QPAMC_m were synthesized and the dilational properties were studied as monolayers by dilational rheological measurements at the water–air and water–<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 QPAMC₈, 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 follow‐up duration. Logistic regression analysis identified ATE risk factors in ICI‐treated patients. Results Overall, the ICI group (n = 2877) demonstrated an ATEs risk 2.01 times higher than the non‐ICI group (RR, 2.01 [95% CI (1.61–2.51)]; p < 0.001). Subgroup analysis revealed no significant increase in ATEs risk for ICI‐treated patients within 1 year (Limited to a max 9‐month follow‐up, p = 0.075). However, ATEs risk in the ICI group rose by 41% at 1 year (p = 0.010) and 97% at 4 years (p ≤ 0.001). Age, diabetes, hypertension, peripheral atherosclerosis, atrial fibrillation, chronic ischemic heart disease, distant cancer metastasis, and ICI treatment cycles contributed to ATEs risk elevation in ICI‐treated patients. Conclusion ICI‐treated patients may exhibit a higher risk of ATEs, especially after 1 year of treatment

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