Wood cellulose films with different foldabilities triggered by dissolution and regeneration from concentrated H2SO4 and NaOH/urea aqueous solutions.

Forests are a major source of wealth for Canadians, and cellulose makes up the "skeleton" of wood fibers. Concentrated H2SO4 and NaOH/urea aqueous solutions are two efficient solvents that can rapidly dissolve cellulose. Our preliminary experiment obtained regenerated wood cellulose films with different mechanical properties from these two solvents. Therefore, herein, we aim to investigate the effects of aqueous solvents on the structure and properties of wood cellulose films. Regenerated cellulose (RC) films were produced by dissolving wood cellulose in either 64 wt% H2SO4 solution (RC-H4) or NaOH/urea aqueous solution (RC-N4). RC-H4 showed the higher tensile strength (109.78 ±â€¯2.14 MPa), better folding endurance (20-28 times), and higher torsion angle (42°) than RC-N4 (62.90 ±â€¯2.27 MPa, un-foldable, and 12°). The increased cellulose contents in the H2SO4 solutions from 3 to 5 wt% resulted in an improved tensile strength from 102.61 ±â€¯1.99 to 132.93 ±â€¯5.64 MPa and did not affect the foldability. RC-H4 also exhibited better water vapor barrier property (1.52 ±â€¯0.04 × 10-7 g-1h-1Pa-1), superior transparency (~90 % transmittance at 800 nm), but lower thermal stability compared to RC-N4. This work provides special insights into the regenerated wood cellulose from two aqueous solvents and is expected to facilitate the development of high-performance RC films from abundant forestry resources.

p53 deficiency mediates cisplatin resistance by upregulating RRM2 and crotonylation of RRM2K283 through the downregulation of SIRT7.

p53 deficiency plays a crucial role in chemotherapy resistance through various biological events, including posttranslational modifications (PTMs). Recently, lysine crotonylation (Kcr) has been shown to play a vital role in cancer progression. However, the global p53-regulated crotonylome and the function of these altered Kcr proteins after p53 deficiency remain unclear. In this study, we used a SILAC-based quantitative crotonylome to identify 3,520 Kcr in 1924 crotonylated proteins in response to p53 knockout. We found that increased crotonylation of RRM2 at K283 (RRM2K283Cr) in the presence of p53 deficiency promoted HCT116 cell resistance to cisplatin. We discovered that SIRT7 could be the decrotonylase of RRM2 and was downregulated after p53 knockout, resulting in increased RRM2K283Cr. Mechanistically, p53 deficiency inhibited cell apoptosis by upregulating RRM2 protein expression and RRM2K283Cr-mediated cleaved-PARP1 and cleaved-caspase3 expression, and SIRT7 was downregulated to upregulate crotonylation of RRM2 upon p53 deficiency. In conclusion, our results indicated that p53 deficiency plays a malignant role in colon cancer resistance to cisplatin therapy by regulating RRM2 protein and RRM2K283Cr expression. Our findings provide a novel therapeutic target against p53-deficient cancer.

Inter-continental variability in the relationship of oxidative potential and cytotoxicity with PM2.5 mass.

Most fine ambient particulate matter (PM2.5)-based epidemiological models use globalized concentration-response (CR) functions assuming that the toxicity of PM2.5 is solely mass-dependent without considering its chemical composition. Although oxidative potential (OP) has emerged as an alternate metric of PM2.5 toxicity, the association between PM2.5 mass and OP on a large spatial extent has not been investigated. In this study, we evaluate this relationship using 385 PM2.5 samples collected from 14 different sites across 4 different continents and using 5 different OP (and cytotoxicity) endpoints. Our results show that the relationship between PM2.5 mass vs. OP (and cytotoxicity) is largely non-linear due to significant differences in the intrinsic toxicity, resulting from a spatially heterogeneous chemical composition of PM2.5. These results emphasize the need to develop localized CR functions incorporating other measures of PM2.5 properties (e.g., OP) to better predict the PM2.5-attributed health burdens.

Sources of acellular oxidative potential of water-soluble fine ambient particulate matter in the midwestern United States.

Ambient fine particulate matter (PM2.5) is associated with numerous health complications, yet the specific PM2.5 chemical components and their emission sources contributing to these health outcomes are understudied. Our study analyzes the chemical composition of PM2.5 collected from five distinct locations at urban, roadside and rural environments in midwestern region of the United States, and associates them with five acellular oxidative potential (OP) endpoints of water-soluble PM2.5. Redox-active metals (i.e., Cu, Fe, and Mn) and carbonaceous species were correlated with most OP endpoints, suggesting their significant role in OP. We conducted a source apportionment analysis using positive matrix factorization (PMF) and found a strong disparity in the contribution of various emission sources to PM2.5 mass vs. OP. Regional secondary sources and combustion-related aerosols contributed significantly (> 75 % in total) to PM2.5 mass, but showed weaker contribution (43-69 %) to OP. Local sources such as parking emissions, industrial emissions, and agricultural activities, though accounting marginally to PM2.5 mass (< 10 % for each), significantly contributed to various OP endpoints (10-50 %). Our results demonstrate that the sources contributing to PM2.5 mass and health effects are not necessarily same, emphasizing the need for an improved air quality management strategy utilizing more health-relevant PM2.5 indicators.

Bio-based melamine formaldehyde resins for flame-retardant polyurethane foams.

The polyurethane (PU) foams can be functionally tailored by modifying the formulation with different additives. One such additive is melamine (MA) formaldehyde resin for improving their flame-retardant properties. In this work, the glycerol-modified (GMF), sodium alginate (SGMF)- and lignosulfonate-modified melamine formaldehyde (LGMF) were prepared and used as flame retardants reacting with isocyanate to prepare the corresponding rigid polyurethane foams (GMF-PU, SGMF-PU and LGMF-PU). The thermomechanical properties and flame-retardant properties of the foams were characterized. The results showed that the specific compression strength of GMF-PU, SGMF-PU and LGMF-PU increased substantially compared to the foams from physical addition of MA, sodium alginate and lignosulfonate, all of which were greater than that of the foam without any flame retardant (PPU). Meanwhile, the cell wall of the foam pores became thicker and the closed pore ratio increased. The sodium alginate and lignosulfonate played a key role in enhancing foam thermal stability. The limiting oxygen index values and cone calorimetry results indicated the flame-retardant efficiency of GMF-PU, SGMF-PU and LGMF-PU was significantly enhanced relative to PPU. Meanwhile, the heat and smoke release results indicated sodium alginate and lignosulfonate could reduce the amount of smoke generation to different degrees during the combustion of the foam.

Apelin receptor dimer: Classification, future prospects, and pathophysiological perspectives.

Apelin receptor (APJ), a member of the class A family of G protein-coupled receptor (GPCR), plays a crucial role in regulating cardiovascular and central nervous systems function. APJ influences the onset and progression of various diseases such as hypertension, atherosclerosis, and cerebral stroke, making it an important target for drug development. Our preliminary findings indicate that APJ can form homodimers, heterodimers, or even higher-order oligomers, which participate in different signaling pathways and have distinct functions compared with monomers. APJ homodimers can serve as neuroprotectors against, and provide new pharmaceutical targets for vascular dementia (VD). This review article aims to summarize the structural characteristics of APJ dimers and their roles in physiology and pathology, as well as explore their potential pharmacological applications.

Low-intensity pulsed ultrasound promotes the osteogenesis of mechanical force-treated periodontal ligament cells via Piezo1.

Background: Low-intensity pulsed ultrasound (LIPUS) can accelerate tooth movement and preserve tooth and bone integrity during orthodontic treatment. However, the mechanisms by which LIPUS affects tissue remodeling during orthodontic tooth movement (OTM) remain unclear. Periodontal ligament cells (PDLCs) are pivotal in maintaining periodontal tissue equilibrium when subjected to mechanical stimuli. One notable mechano-sensitive ion channel, Piezo1, can modulate cellular function in response to mechanical cues. This study aimed to elucidate the involvement of Piezo1 in the osteogenic response of force-treated PDLCs when stimulated by LIPUS. Method: After establishing rat OTM models, LIPUS was used to stimulate rats locally. OTM distance and alveolar bone density were assessed using micro-computed tomography, and histological analyses included hematoxylin and eosin staining, tartrate-resistant acid phosphatase staining and immunohistochemical staining. GsMTx4 and Yoda1 were respectively utilized for Piezo1 functional inhibition and activation experiments in rats. We isolated human PDLCs (hPDLCs) in vitro and evaluated the effects of LIPUS on the osteogenic differentiation of force-treated hPDLCs using real-time quantitative PCR, Western blot, alkaline phosphatase and alizarin red staining. Small interfering RNA and Yoda1 were employed to validate the role of Piezo1 in this process. Results: LIPUS promoted osteoclast differentiation and accelerated OTM in rats. Furthermore, LIPUS alleviated alveolar bone resorption under pressure and enhanced osteogenesis of force-treated PDLCs both in vivo and in vitro by downregulating Piezo1 expression. Subsequent administration of GsMTx4 in rats and siPIEZO1 transfection in hPDLCs attenuated the inhibitory effect on osteogenic differentiation under pressure, whereas LIPUS efficacy was partially mitigated. Yoda1 treatment inhibited osteogenic differentiation of hPDLCs, resulting in reduced expression of Collagen Ⅰα1 and osteocalcin in the periodontal ligament. However, LIPUS administration was able to counteract these effects. Conclusion: This research unveils that LIPUS promotes the osteogenesis of force-treated PDLCs via downregulating Piezo1.

Cost-Utility Analysis of Vericiguat in Heart Failure with Reduced Ejection Fraction After Worsening Heart Failure Events in China.

OBJECTIVE: Vericiguat is a new medication to demonstrate clinical efficacy in heart failure with reduced ejection fraction (HFrEF) after worsening heart failure (WHF) events, but its cost-utility was unknown. We aimed to assess the cost-utility of combining the application of vericiguat with standard treatment in HFrEF patients who had WHF events. METHODS: A multistate Markov model was implemented to mimic the economic results of HFrEF patients who had WHF events in China after receiving vericiguat or placebo. An analysis of cost-utility was conducted; most parameters were set according to the published studies and related databases. All the utilities and costs were decreased at a rate of 5% annually. The incremental cost-effectiveness ratios (ICERs) were the primary outcome measure. We also conducted sensitivity analyses. RESULTS: Over a 20 year lifetime horizon, additional use of vericiguat led to an elevated cost from US$9725.03 to US$20,660.76 at the current vericiguat costs. This was related to increased quality-adjusted life years (QALYs) from 2.50 to 2.66, along with an ICER of US$65,057.24 per QALY, which was over the willingness-to-pay (WTP) threshold of US$36,096.30 per QALY. If the vericiguat costs were discounted at 80%, it contributed to an ICER of US$12,226.77 per QALY. Additional use of vericiguat for patients with plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) of ≤ 5314 pg per ml produced an ICER of US$23,688.46 per QALY. The outcomes of the one-way sensitivity analysis showed the risk of death from cardiovascular disease in both groups was variable with the highest sensitivity. The probabilistic sensitivity analysis showed that 41.6% of the mimicked population receiving vericiguat combined with standard therapy was cost-effective at the WTP threshold of US$36,096.30 per QALY. CONCLUSIONS: From the perspective of Chinese public healthcare system, the combined use of vericiguat and standard treatment in patients with HFrEF following WHF events did not generate advantages in cost-utility in China but was a cost-effective therapeutic strategy for those who with plasma NT-proBNP of ≤ 5314 pg per ml.

Design and Synthesis of Novel Ultralong-Acting Peptides as EDP-EBP Interaction Inhibitors for Pulmonary Fibrosis Treatment.

The increased remodeling of the extracellular matrix (ECM) in pulmonary fibrosis (PF) generates bioactive ECM fragments called matricryptins, which include elastin-derived peptides (EDPs). The interaction between EDPs and their receptors, including elastin-binding protein (EBP), plays a crucial role in exacerbating fibrosis. Here, we present LXJ-02 for the first time, a novel ultralong-acting inhibitor that disrupts the EDPs/EBP peptide-protein interaction, promoting macrophages to secrete matrix metalloproteinase-12 (MMP-12), and showing great promise as a stable peptide. MMP-12 has traditionally been implicated in promoting inflammation and fibrosis in various acute and chronic diseases. However, we reveal a novel role of LXJ-02 that activates the macrophage-MMP-12 axis to increase MMP-12 expression and degrade ECM components like elastin. This leads to the preventing of PF while also improving EDP-EBP interaction. LXJ-02 effectively reverses PF in mouse models with minimal side effects, holding great promise as an excellent therapeutic agent for lung fibrosis.

Ionizable Lipids from Click Reactions for Lipid Nanoparticle Assembling and mRNA Delivery.

Ionizable lipid-containing lipid nanoparticles (LNPs) are regarded as promising nonviral vectors for gene therapy delivery systems. Rationale design of the ionizable lipid structure based on initial screening of ionizable lipid molecule libraries combined with systematic comparison and analysis on the physical chemical parameters related to delivery efficiency greatly accelerated the discovery of novel LNP candidates for delivering various nucleic acid therapeutics like mRNAs (mRNAs). Based on the copper-catalyzed azide-alkyne click reaction, which is highly efficient and biocompatible, we were able to obtain the lipid molecule library containing a common triazole moiety between different lipid tails and various substituents as hydrophilic head groups. Herein, we systematically investigated the change of pKa values of different ionizable lipid molecules with different substituents as head groups in the click-based lipid library, mapping the pKa value change to different steps in the process of the LNP assembly and mRNA delivery. Systematic analyses on the data including the pKa value of the ionized lipids and the encapsulation and delivery efficiency of mRNA in LNPs with these ionized lipids provided the possibility of rational design on the head and tail structure for the triazole containing ionized lipids to realize highly efficient delivery of different mRNAs.

A Near-Infrared Fluorescent Probe for the Rapid Detection of Nitroxyl in Living Cells.

Nitroxyl (HNO) plays an important role in various physiological activities. It has the potential to be used as a treatment for certain diseases such as alcohol poisoning, acute hypertension, and atherosclerosis. However, traditional methods for detecting HNO are challenging due to its rapid polymerization and elimination into N2O. Therefore, it is crucial to establish direct and effective HNO detection methods to comprehend these physiological processes better. In this study, a new near-infrared fluorescent probe called HXM-P based on the intramolecular charge transfer (ICT) mechanism was designed and synthesized. This probe employs 2-((6-hydroxy-2,3dihydro-1 H-xanthen-4-yl)methylene)malononitrile as a fluorophore and 2-(diphenylphosphine) benzoate as a recognition group. The results showed that probe HXM-P can detect HNO with high sensitivity (1.07 × 10- 8 M). A good linear correlation was observed between the fluorescence intensities at 640 nm and the concentrations of HNO in the range of 0-80 µM (R2 = 0.997). Moreover, probe HXM-P exhibited a rapid response rate (within 15 s) toward HNO, and the fluorescent intensity reached a plateau within 5 min, making it easier to track the highly reactive and short-lived HNO in living systems. Additionally, HXM-P was successfully employed for imaging HNO in HepG2 cells.

TMEM119 (c.G143A, p.S48L) Mutation Is Involved in Primary Failure of Eruption by Attenuating Glycolysis-Mediated Osteogenesis.

Primary failure of eruption (PFE) is a rare oral disease with an incidence rate of 0.06%. It is characterized by abnormal eruption mechanisms that disrupt tooth eruption. The underlying pathogenic genetic variant and mechanism of PFE remain largely unknown. The purpose of this study was to explore the role of a novel transmembrane protein 119 (TMEM119) mutation in two PFE patients in a Chinese family. Information collection was performed on the family with a diagnosis of PFE, and blood samples from patients and healthy family members were extracted. Whole-exome sequencing was performed. Bioinformatics analysis revealed that a heterozygous variant in the TMEM119 gene (c.G143A, p.S48L) was a disease-associated mutation in this family. Recombinant pcDNA3.1 plasmid-containing wild-type and mutant TMEM119 expression cassettes were successfully constructed and transfected into MC3T3-E1 cells, respectively. The results of in vitro analysis suggested that the subcellular distribution of the TMEM119 protein was transferred from the cell cytoplasm to the nucleus, and the ability of cells to proliferate and migrate as well as glycolytic and mineralized capacities were reduced after mutation. Furthermore, rescue assays showed that activating transcription factor 4 (ATF4) overexpression rescued the attenuated glycolysis and mineralization ability of cells. Results of in vivo analysis demonstrated that TMEM119 was mainly expressed in the alveolar bone around the mouse molar germs, and the expression level increased with tooth eruption, demonstrated using immunohistochemistry and immunofluorescence. Collectively, the novel TMEM119 mutation is potentially pathogenic in the PFE family by affecting the glucose metabolism and mineralized function of osteoblasts, including interaction with ATF4. Our findings broaden the gene mutation spectrum of PFE and further elucidate the pathogenic mechanism of PFE.

Understanding the Impact of Sheep Digestion on Seed Germination in the Cold Desert Annual Diptychocarpus strictus with Emphasis on Fruit and Seed Heteromorphism.

This study aimed to investigate the morphological characteristics of fruits and seeds from Diptychocarpus strictus, a plant species inhabiting the cold desert pastoral area of China. Furthermore, this study sought to evaluate the germination potential of these seeds following digestion by sheep. This study employed the sheep rumen fistula method to simulate rumen digestion at various time intervals. Subsequently, an in vitro simulation method was utilized to simulate true gastric and intestinal digestion after rumen digestion. Paper germination tests were then conducted to assess the impact of the digestive process on the heteromorphic seed morphology and germination. During rumen digestion, the seeds were protected by wide wings. The results revealed a highly significant negative correlation (p < 0.01) between seed wing length and digestion time. Post-rumen digestion, variations in the germination rate among seeds from fruits at different locations were observed. Indicators, such as germination rate, exhibited a highly significant negative correlation with rumen digestion time (p < 0.01). In vitro simulated digestion tests demonstrated that Diptychocarpus strictus seeds retained their ability to germinate even after complete digestion within the livestock's digestive tract. The polymorphic nature of Diptychocarpus strictus seeds, coupled with their capacity to survive and germinate through the digestive tract, facilitates the spread of these seeds. This finding has implications for mitigating desert grassland degradation and promoting sustainable ecological development.

Internal exposure potential of water-soluble organic molecules in urban PM2.5 evaluated by non-covalent adductome of human serum albumin.

Water-soluble organic molecules (WSOMs) in inhaled PM2.5 can readily translocate from the lungs into the blood circulation, facilitating their distribution to and health effects on distant organs and tissues in the human body. Human serum albumin (HSA), the most abundant protein carrier in the blood, readily binds exogenous substances to form non-covalent adducts and subsequently transports them throughout the circulatory system, thereby indicating their internal exposure. The direct internal exposure of WSOMs in PM2.5 needs to be understood. In this study, the non-covalent HSA-WSOM adductome was developed as a dosimeter to evaluate the internal exposure potential of WSOMs in urban PM2.5. The WSOM composition was acquired from non-target high-resolution mass spectrometry analysis coupled with multiple ionizations. The binding level of HSA-WSOM non-covalent adducts was obtained from surface plasma resonance. Machine learning combined WSOM composition and the binding level of HSA-WSOM non-covalent adducts to screen bindable (also internalizable) WSOMs. The concentration of WSOM ranged from 4 to 13 µg/m3 during our observation period. Of the 17,513 mass spectral features detected, 9,484 contributed to the non-covalent adductome and possessed the internal exposure potential. 102 major contributors accounted for 90.6 % of the HSA-WSOM binding level. The fraction of internalizable WSOMs in PM2.5 varied from 11.9 % to 61.3 %, averaging 26.2 %. WSOMs that have internal exposure potential were primarily lignin-like and lipid-like substances. The HSA-WSOMs non-covalent adductome represents direct internal exposure potential, which can provide crucial insights into the molecular diagnosis of PM2.5 exposure and precise assessments of PM2.5 health effects.

An interval AQI combination prediction model based on multiple data decomposition and information aggregation operator.

In this paper, an interval Air Quality Index (AQI) combination prediction model based on EEMD, VMD, and the weighted power average (WPA) operator is proposed. EEMD and VMD decompose complex AQI data effectively, while WPA operator reasonably aggregates the prediction results of different models. We validate the effectiveness of the proposed model using Shenzhen's daily interval AQI. Furthermore, three kinds of prediction models are compared with the proposed model to highlight its advantages from various perspectives. The results show that the introduction of data decomposition methods significantly improves the model's prediction accuracy, WPA operator further enhances the model's prediction capability, and the incorporation of EEMD and VMD enables the proposed model to have stronger feature extraction capabilities for complex time series. As a result, the model proposed in this paper demonstrates strong generalization ability and prediction accuracy, making it applicable not only for air quality prediction but also for other domains such as economics and environment.

Genomic evidence for climate-linked diversity loss and increased vulnerability of wild barley spanning 28 years of climate warming.

The information on how plant populations respond genetically to climate warming is scarce. Here, landscape genomic and machine learning approaches were integrated to assess genetic response of 10 wild barley (Hordeum vulgare ssp. spontaneum; WB) populations in the past and future, using whole genomic sequencing (WGS) data. The WB populations were sampled in 1980 and again in 2008. Phylogeny of accessions was roughly in conformity with sampling sites, which accompanied by admixture/introgressions. The 28-y climate warming resulted in decreased genetic diversity, increased selection pressure, and an increase in deleterious single nucleotide polymorphism (dSNP) numbers, heterozygous deleterious and total deleterious burdens for WB. Genome-environment associations identified some candidate genes belonging to peroxidase family (HORVU2Hr1G057450, HORVU4Hr1G052060 and HORVU4Hr1G057210) and heat shock protein 70 family (HORVU2Hr1G112630). The gene HORVU2Hr1G120170 identified by selective sweep analysis was under strong selection during the climate warming of the 28-y, and its derived haplotypes were fixed by WB when faced with the 28-y increasingly severe environment. Temperature variables were found to be more important than precipitation variables in influencing genomic variation, with an eco-physiological index gdd5 (growing degree-days at the baseline threshold temperature of 5 °C) being the most important determinant. Gradient forest modelling revealed higher predicted genomic vulnerability in Sede Boqer under future climate scenarios at 2041-2070 and 2071-2100. Additionally, estimates of effective population size (Ne) tracing back to 250 years indicated a forward decline in all populations over time. Our assessment about past genetic response and future vulnerability of WB under climate warming is crucial for informing conservation efforts for wild cereals and rational use strategies.

Multifunctional self-healing hydrogels via nanoengineering of colloidal and polymeric cellulose.

The unique features of self-healing hydrogels hold great potential for biomedical applications including injectable hydrogels for cancer treatment, procedures for tumor removal or resection. However, the fabrication of durable and multifunctional self-healing hydrogels composed of biocompatible, green building blocks via versatile synthetic methodology continues to pose a significant challenge. Here, we engineered dialdehyde cellulose (DAC, as a macromolecular bio-crosslinker), and electrosterically stabilized nanocrystalline cellulose (ENCC, as a ligand-targeted drug carrier) to facilitate a strategy for the construction of self-healing hydrogels. Benefiting from its high carboxyl group density, ENCC was functionalized with folic acid (FA) using a non-toxic DMTMM coupling agent and loaded with doxorubicin (DOX, a model drug) through electrostatic interactions. A natural self-healing hydrogel was prepared from carboxymethyl chitosan (CCTS) and DAC mixed with DOX-loaded FA-ENCC using dynamic Schiff-base and hydrogen linkages. A combination of active supramolecular and vital covalent junctions led to a soft (storage modulus ∼500 Pa) and durable material, with rapid (< 5 min) reconstruction of molecular structure from fractured and injected to intact forms. The DAC-CCTS hydrogel showed an appreciable loading capacity of ∼5 mg g-1. Biocompatibility of the hydrogels was evaluated using cell viability and metabolic activity assays, showing lower metabolic activity due to sustained release of its cargo. These materials offer a versatile, sustainable, and green platform for the efficient construction of hydrogels, based on macro- and nano-engineered cellulose, the most abundant and easily accessible biopolymer.

A Convenient and Effective Preoxygenation Technique for Prolonging Deep Inspiration Breath-Hold Duration With a Venturi Mask With a 50% Oxygen Concentration.

PURPOSE: Voluntary deep inspiration breath-hold (DIBH) is commonly used in radiation therapy (RT), but the short duration of a single breath-hold, estimated to be around 20 to 40 seconds, is a limitation. This prospective study aimed to assess the feasibility and safety of using a simple preoxygenation technique with a Venturi mask to prolong voluntary DIBH. METHODS AND MATERIALS: The study included 33 healthy volunteers and 21 RT patients. Preoxygenation was performed using a Venturi mask with a 50% oxygen concentration. Paired t tests compared the duration of a single DIBH in room air and after 5, 15, and 30 minutes of preoxygenation in healthy volunteers. Sustainability of breath-hold and tolerability of heart rate and blood pressure were assessed for multiple DIBH durations in both volunteers and patients. RESULTS: In healthy volunteers, a 15-minute preoxygenation significantly prolonged the duration of a single DIBH by 24.95 seconds compared with 5-minute preoxygenation (89 ± 27.76 vs 113.95 ± 30.63 seconds; P < .001); although there was a statistically significant increase in DIBH duration after 30-minute preoxygenation, it was only extended by 4.95 seconds compared with 15-minute preoxygenation (113.95 ± 30.63 vs 118.9 ± 29.77 seconds; P < .01). After 15-minute preoxygenation, a single DIBH lasted over 100 seconds in healthy volunteers and over 80 seconds in RT patients, with no significant differences among 6 consecutive cycles of DIBH. Furthermore, there were no significant differences in heart rate or blood pressure after DIBHs, including DIBH in room air and 6 consecutive DIBHs after 15-minute preoxygenation (all P > .05). CONCLUSIONS: Preoxygenation with a 50% oxygen concentration for 15 minutes effectively prolongs the duration of 6 cycles of DIBH both in healthy volunteers and RT patients. The utilization of a Venturi mask to deliver 50% oxygen concentration provides a solution characterized by its convenience, good tolerability, and effectiveness.