Linear Polyethylene with Ketone Groups for Photodegradability: Higher Efficiency with Side-Chain Carbonyls than In-Chain.

In this study, linear polyethylenes bearing ketone groups in their side-chains were prepared by palladium-catalyzed copolymerization of ethylene and methyl vinyl ketone (poly(E/MVK)) and the photodegradation behavior was compared with polyethylene bearing in-chain carbonyl groups (poly(E/CO)). Poly(E/MVK) showed a faster photodegradation rate and a more significant decrease of the molecular weight than poly(E/CO). By H NMR analysis, both Norrish type I and type II scissions are involved for the degradation of poly(E/MVK), probably due to the existence of MVK groups in amorphous region, which is preferable for the radical chain reactions and the main chain cleavage.

Single-Molecule Reactor Based on the Excluded Volume Effect of Bottlebrush Polymers.

Precise spatiotemporal control of chemical reactions, as in living organisms, is a longstanding challenge in chemistry. Herein, we develop a bottlebrush polymer reactor (BBPR), which is a simple yet versatile single-molecule reactor consisting of a bottlebrush polymer that can spatially confine various polymerization reactions. The dense side chains of bottlebrush polymers generate a strong excluded volume effect (EVE) that effectively prevents reactions between the backbone chains of individual BBPRs.

Polyethyleneketones with Controlled Spacer Units: Synthesis, Characterization, and Photodegradation.

In this study, a new synthetic method for structurally controlled polyethyleneketones, a photodegradable polyethylene-like polymer, has been developed. Telechelic Zn-polyethylene was prepared from α,ω-diene, diethylzinc, and ethylene, which was allowed to react with diacid chlorides to give polyethyleneketones with defined spacing between the neighboring ketone functionalities. The photodegradation of these polymers under UV light demonstrated a degradation rate dependency on the spacer units between the carbonyl groups.

Star Polymer Network Elastomer with Reconfigurable Network Structure via Covalent Bond Exchange through Olefin Metathesis.

A covalent adaptable network (CAN) elastomer with a well-defined network structure was fabricated by end-linking monodisperse star polymers via associative dynamic covalent bonds (DCBs). Monodisperse 4-arm star-shaped polyesters with vinyl end groups were synthesized and end-linked by an olefin metathesis reaction, yielding an elastomer with a uniform chain length between cross-links. The well-defined network structure endowed the elastomer with good mechanical properties.

Comprehensive serum biomarker analysis reveals IL-8 changes as the only predictor of the effectiveness of immune checkpoint inhibitors for patients with advanced non-small cell lung cancer.

Objectives: Programmed cell death ligand 1 (PD-L1) expression is widely used to predict the effectiveness of PD-(L)1 inhibitors despite its imperfection. Previous studies suggested the utilization of various serum biomarkers; nonetheless, findings are inconclusive because of limited sample sizes or the focus on a single biomarker in many of these studies. This study analyzed multiplex serum biomarkers to explore their predictive ability in a large cohort of patients with advanced non-small-cell lung cancer (NSCLC) treated with a PD-L1 inhibitor in a real-world setting.

Habu vipers (Protobothrops flavoviridis) are an overlooked but important reservoir of the zoonotic tick Amblyomma testudinarium (Acari: Ixodidae) in subtropical Asia.

Subtropical Asia has a rich diversity of reptiles and ticks, though the role of reptiles in the sylvatic cycles of medically important ticks in the region is poorly known. Habu vipers (Protobothrops flavoviridis) are widespread and common in the Japanese subtropics but their role as hosts for ticks has not been carefully explored. For 15 months in 2023/24, habu vipers were screened for ticks and were found to be important hosts for immature stages of the tick Amblyomma testudinarium, with a 22 % infestation rate.

Synthesis of Long-Chain Polyamides via Main-Chain Modification of Polyethyleneketones.

Long-chain polyamides (polyethyleneamides) were prepared from polyethylenes bearing in-chain carbonyl groups (polyethyleneketones) by the oxime formation and successive Beckmann rearrangement. (Diethylamino)sulfur trifluoride (DAST) was utilized as a promoter, which allowed mild conversion of the oxime group in spite of low solubility of the polymers. The polyethyleneamide exhibited different tensile property compared to a commercial HDPE.

Effects of Alkyl Ester Chain Length on the Toughness of PolyAcrylate-Based Network Materials.

Polyacrylate-based network materials are widely used in various products owing to their facile synthesis via radical polymerization reactions. In this study, the effects of alkyl ester chains on the toughness of polyacrylate-based network materials were investigated. Polymer networks were fabricated via the radical polymerization of methyl acrylate (MA), ethyl acrylate (EA), and butyl acrylate (BA) in the presence of 1,4-butanediol diacrylate as a crosslinker.

Effectiveness and Safety of Atezolizumab Monotherapy in Previously Treated Japanese Patients With Unresectable Advanced or Recurrent NSCLC: A Multicenter, Prospective, Observational Study (J-TAIL).

Introduction: The efficacy and safety of atezolizumab in previously treated patients with NSCLC have been established in the registrational phase 3 OAK trial. In this study, we evaluated the effectiveness and safety of atezolizumab monotherapy in a large real-world cohort to confirm the reproducibility of the results of the registrational trial.

Methods: This was a multicenter, prospective, single-arm observational study.

Effects of network junctions and defects on the crystallization of model poly(ethylene glycol) networks.

Polymer crystallization drastically changes the physical properties of polymeric materials. However, the crystallization in polymer networks has been little explored. This study investigated the crystallization behavior of a series of poly(ethylene glycol) (PEG) networks consisting of well-defined branched precursors.

Linking microscopic structural changes and macroscopic mechanical responses in a near-ideal bottlebrush elastomer under uniaxial deformation.

Bottlebrush (BB) elastomers, in which load-bearing network strands are densely grafted with side chains, are gaining much attention due to their unique mechanical properties. Herein, we used small-angle X-ray scattering coupled with tensile tests to investigate the microscopic structural changes induced in a model BB elastomer with a controlled network structure under uniaxial deformation. The model BB elastomer was synthesized by end-linking a monodisperse star-shaped BB polymer, which ensured a controlled network structure.

Impact of Tumor Assessment Frequency on Statistical Power in Randomized Cancer Clinical Trials Evaluating Progression-Free Survival.

Background: Progression-free survival (PFS) is frequently used as a primary endpoint in late-phase clinical trials for anti-metastatic cancer agents. Previous studies have indicated that the frequency of tumor assessment affects the statistical power for PFS because progression dates are inaccurate; however, this finding may be difficult to generalize because of its unrealistic assumptions. Therefore, we re-examined this issue under realistic assumptions and various scenarios that approximate actual clinical trials.

Synthesis of a Bottlebrush Polymer Gel with a Uniform and Controlled Network Structure.

A structurally controlled polymer gel was synthesized by end-linking a monodisperse star polymer in which each arm was a bottlebrush (BB) polymer densely grafted with side chains. The combination of atom transfer radical polymerization and postpolymerization modification yielded a four-arm star-shaped BB polymer with a controlled polymerization degree of the backbone and side chains. The reactive end groups introduced at the end of each arm reacted with small bifunctional linkers in solution, leading to the formation of a BB polymer gel.

A Simple and Versatile Method for the Construction of Nearly Ideal Polymer Networks.

Polymer networks usually contain numerous inhomogeneities that deteriorate their physical properties and should be eliminated to create reliable, high-performance materials. A simple method is introduced for the production of nearly ideal networks from various vinyl polymers through controlled polymerization and subsequent crosslinking. Monodisperse star polymers with bromide end groups were synthesized by atom-transfer radical polymerization and end-linked with dithiol linkers using thiol-bromide chemistry.

Restricted mean survival time as a summary measure of time-to-event outcome.

Many clinical research studies evaluate a time-to-event outcome, illustrate survival functions, and conventionally report estimated hazard ratios to express the magnitude of the treatment effect when comparing between groups. However, it may not be straightforward to interpret the hazard ratio clinically and statistically when the proportional hazards assumption is invalid. In some recent papers published in clinical journals, the use of restricted mean survival time (RMST) or τ-year mean survival time is discussed as one of the alternative summary measures for the time-to-event outcome.

Efficacy of trastuzumab emtansine in Japanese patients with previously treated HER2-positive locally advanced or metastatic gastric or gastroesophageal junction adenocarcinoma: A subgroup analysis of the GATSBY study.

Aim: The phase II/III GATSBY study (NCT01641939) showed that trastuzumab emtansine did not have an efficacy benefit over taxane in patients with previously treated, human epidermal growth factor receptor 2 (HER2)-positive advanced or metastatic gastric or gastroesophageal junction cancer. We evaluated patients from Japanese centers within GATSBY.

Methods: In stage one, patients (randomized 2:2:1) received trastuzumab emtansine 3.