化学最新文献

A simple gas sensor consisting of a molecularly imprinted polymer-carbon nanotube composite cast onto a screen-printed electrode has been developed with extremely high selectivity for ethanol vapour over methanol vapour. Ethanol gas sensors typically display selectivity for ethanol over methanol in the range 2-4 times, while the mean ratio of ethanol to methanol response observed with the described device was 672. This selectivity was achieved under ambient conditions. Additionally, the molecularly imprinted polymer was produced using reagents previously applied in the development of a device selective for methanol, with only the template being changed. This demonstrates the versatility of molecular imprinting and provides a foundation for their greater integration into future gas sensors.

On-site quantitative detection of organophosphorus pesticides (OPs) is crucial for safeguarding food and public safety. This study presents a novel acetylcholinesterase (AChE)-mediated paper-based Au³⁺-etching of gold nanobipyramids (AuNBPs) system. The system employs a long-term storable AuNBPs-deposited nylon membrane embedded within a portable and temperature-controlled paper-based analytical device. This system, coupled with a colorimeter-based quantitative method, enables the development of a practical paper-based multicolor sensor (PMS) for on-site quantitative detection of three common OPs (paraoxon, dichlorvos, and trichlorfon). In the absence of OPs, AChE hydrolyzes acetylthiocholine to thiocholine, which reduces Au³⁺ to Au⁺. The presence of OPs inhibits AChE activity, thereby preserving Au³⁺ to etch AuNBPs on nylon membranes, accompanied by multicolor changes. These color changes can be simply quantified by measuring the a∗ parameter of the CIELab color space using a portable colorimeter. Under optimal conditions, the PMS displayed eight OPs-corresponding color changes with a minimum detectable concentration of 1.0-10 μg/L (visual observation) and limits of detection of 0.8-7.2 μg/L (colorimeter) and 0.2-3.4 μg/L (UV-vis spectrometry). The PMS successfully determined the OPs in vegetable and rice samples with recoveries of 89.0-109 % and RSDs (n = 5) of <6 %. These results were consistent with those obtained using the HPLC-MS method. The PMS demonstrates excellent portability, AuNBPs stability, detection sensitivity, and reproducibility, making it a promising tool for the on-site quantitative detection of OPs residues in food. Furthermore, the paper-based etching system coupled with the colorimeter-based quantitative method provides a valuable reference to develop practical PMSs for various targets in diverse fields.

Hesperetin is the aglycone of hesperidin and is widely found in the Rutaceae plants and herbal medicines. It exhibits antioxidant, detoxifying, anti-inflammatory, and antimicrobial properties, similar to hesperidin. It has also shown potential in the regulation of certain diseases. In order to detect hesperetin in complex matrix samples such as citrus and herbal, we developed an anti-hesperetin monoclonal antibody and established an indirect competitive enzyme-linked immunosorbent assay (icELISA). The half maximal inhibitory concentration (IC₅₀) was determined to be 2.03 ng/mL, the detection range was 0.39-12.73 ng/mL. In practical sample testing, the concentration of hesperidin measured by icELISA is consistent with the result of UPLC-MS/MS, and the correlation coefficient (R²) is 0.97. These results showed that the established method has good accuracy, reproducibility and broad application prospects, and can be used for the detection of hesperetin in complex matrix samples (such as citrus and herbal samples).

In native tissues, cells encounter a diverse range of stiffness, which can significantly affect their behavior and function. The ability of cells to sense and respond to these mechanical cues is essential for various physiological processes, including cell migration. Cell migration is a complex process influenced by multiple factors, with substrate stiffness emerging as a critical determinant. This study developed a technique to edit the stiffness of polyacrylamide (PAA) hydrogel substrates by adjusting the grayscale level of a photomask during photopolymerization. By analyzing cell morphologies on the hydrogel, we confirmed the development of a single PAA hydrogel substrate with continuous stiffness gradients. This method was used to explore the correlation between substrate stiffness and cell migration dynamics. The study found that cells typically migrated from softer to stiffer surfaces. When the cells initially located on stiffer surfaces, they were able to travel longer distances. Additionally, a continuous 2D stiffness gradient surface was fabricated to explore how cells migrate on smoother versus steeper stiffness gradients. The results showed that cells tended to migrate more readily on smoother stiffness gradient surfaces compared to steeper ones. This study provides valuable insights into cell migration dynamics on substrates with varying stiffness gradients. The results underscore the importance of the mechanical environment in cancer cell migration and offer promising directions for developing interventions to prevent cancer spread.

The concentration elevation of myocardial microRNA (miRNA) biomarker is associated with the pathogenic process of acute myocardial infarction (AMI), and sensitive quantification of myocardial miRNA biomarker plays an important role for early AMI diagnosis and its treatment. In response, this work describes an ultrasensitive and non-label electrochemical biosensor for the assay of myocardial miRNA based on cascade signal amplifications integrated by DNAzyme walker and hemin/G-quadruplex nanowires. The DNAzyme walker is activated by presence of target miRNAs to move along the electrode surface to cyclically cleave the substrate hairpins to release G-quadruplex segments, which further trigger the in situ formation of many hemin/G-quadruplex nanowires. The large amounts of hemin intercalated into the DNA nanowires subsequently generate drastically magnified electrochemical current signals for highly sensitive label-free assay of myocardial miRNAs down to 15.7 fM within dynamic range of 100 fM to 10 nM. Such a biosensor also has high selectivity and can monitor myocardial miRNAs in diluted serums at low levels, providing a sensitive and reliable platform for diagnosing infarct-associated cardiovascular diseases.

The specific detection of peroxydisulfate (S₂O₈^2-, PDS) is significant and challenging due to the rapid development of PDS-related technologies and their widespread application in multiple fields. However, traditional analytical methods are mainly based on their strong oxidizing properties, making it difficult to simultaneously achieve specific identification and high sensitivity for PDS detection in complex water environments. Here, we purposely prepared amino-rich SiQDs (N-SiQDs) as an effective catalyst and introduced H₂O₂ acts as a co-reactant for PDS activation and determination with strong intrinsic chemiluminescence (CL) emission. High yield of reactive active oxygen (mainly O₂˙^- and ˙OH) were generated during CL process, which trigger electron-hole annihilation between the N-SiQDs˙⁺ and N-SiQDs˙^- accounted for extraordinary CL emission. On this basis, a new CL assay for PDS detection was fabricated with broad linear range of 5 × 10^-7M-5 × 10^-5 M and low detection limit (3.2 × 10^-7 M). Due to the absence of SO₄˙^- involvement during CL emission, the sensing platform is sensitive enough, satisfactory selectivity and does not respond to transition-metal ions and inorganic anions that have interferences in the PDS CL sensors reported before. This work not only deepens insight into the mechanisms of nanomaterials assisted PDS activation but also provides a new perspective on the modified metal-free QDs CL probe for chemical species detection.

Objectives: (1) To describe ACPT implementation frequency in practice. (2) To assess associations of ACPT documentation with a) hospital care consumption, including systemic anti-tumor treatment in the last month(s) of life, and b) match between preferred and actual place of death, among oncology patients. Methods: A retrospective cohort study was performed. Data concerning ACPT documentation, hospital care consumption, and preferred and actual place of death were extracted from electronic patient records. Patients with completely documented ACPT (cACPT) and no ACPT were compared using multivariable logistic regression analyses. Results: ACPT was implemented in 64.5% (n = 793) of all deceased patients (n = 1230). In 17.6% (n = 216), preferred place of care or death was documented at least three months before death (cACPT). A cACPT was not associated with systemic anti-tumor treatment (Adjusted OR (AOR): 0.976; 95% CI: 0.642-1.483), but patients with cACPT had fewer diagnostic tests (AOR: 0.518; CI: 0.298-0.903) and less contacts with hospital disciplines (AOR: 0.545; CI: 0.338-0.877). In patients with cACPT, a match between preferred and actual place of death was found for 83% of the patients for whom the relevant information was available (n = 117/n = 141). In patients without ACPT, this information was mostly missing. Conclusion: Although the ACPT was implemented in two thirds of patients, timely documentation of preferred place of care or death is often missing. Yet, timely documentation of these preferences may promote out-hospital-death and save hospital care consumption.

Designing inexpensive, high-efficiency and durable bifunctional catalysts for urea oxidation reaction (UOR) and hydrogen evolution reaction (HER) is an encouraging tactic to produce hydrogen with reduced energy expenditure. Herein, oxygen vacancy-rich cobalt hydroxide/aluminum oxyhydroxide heterostructure on nickel foam (denoted as Co(OH)₂/AlOOH/NF-100) has been fabricated using one step hydrothermal process. Theoretical calculation and experimental results indicate the electrons transfer from Co(OH)₂ to highly active AlOOH results in the interfacial charge redistribution and optimization of electronic structure. Abundant oxygen vacancies in the heterostructure could improve the conductivity and simultaneously serve as the active sites for catalytic reaction. Consequently, the optimal Co(OH)₂/AlOOH/NF-100 demonstrates excellent electrocatalytic performance for HER (62.9 mV@10 mA cm^-2) and UOR (1.36 V@10 mA cm^-2) due to the synergy between heterointerface and oxygen vacancies. Additionally, the in situ electrochemical impedance spectrum (EIS) for UOR suggests that the heterostructured catalyst exhibits rapid reaction kinetics, mass transfer and current response. Importantly, the urea-assisted electrolysis composed of the Co(OH)₂/AlOOH/NF-100 manifests a low cell voltage (1.48 V @ 10 mA cm^-2) in 1 M KOH containing 0.5 M urea. This work presents a promising avenue to the development of HER/UOR bifunctional electrocatalysts.

Background: Advancement in treatment has led to prolonged survival and a rising number of women living with metastatic breast cancer (MBC) in the United States. Due to its high symptom burden, it is recommended that palliative care be integrated into the standard care to help improve quality of life. However, little is known about the use of palliative care among MBC patients in the nation.

Objectives: To determine utilization of palliative care consult (PCC) after metastasis and the influence of PCC on healthcare utilization in the end of life among women living with MBC in the US.

Methods: This retrospective cohort study examined a national electronic health record database to quantify the PCC use after metastasis diagnosis until death and the associations of PCC with Emergency Department (ED), Intensive Care Unit (ICU), and chemotherapies in the end-of-life women (age ≥ 18 years) living with MBC.

Results: From a cohort of 2615 deceased MBC patients, 37% received PCC in the last 6 months of life. Patients who had received PCC in the end-of-life were more likely to be hospitalized, admitted to ED and ICU, and receive chemotherapies in the last 60 days before death. However, patients who had received end-of-life PCC had less hospital and ED visits and received less chemotherapies after PCC initiated.

Conclusion: While PCC can reduce end-of-life aggressive interventions, it was underutilized among patients with MBC in the end-of-life. A myriad of clinical and patient factors may still challenge timely consultation. We urge for future endeavors in developing strategies to remove barriers in the implementation, especially earlier in the disease course, to assure timely PC treatments and reduce discomfort amid aggressive interventions for MBC.

In the recent years, the number of Point-Of-Care-Tests (POCTs) available for clinical diagnostic has steadily increased. POCTs provide a near-patient testing with the potential to generate a result quickly so that appropriate treatment can be implemented, leading to improved clinical outcomes compared to traditional laboratory testing. Technological advances, such as miniaturization of sensors and improved instrumentation, have revolutionized POCTs, enabling the development of smaller and more accurate devices. In this context, it has also gained increasing importance the screening of various analytes simultaneously to increase specificity and improve the characterization of the disease. This study is aimed at developing and characterizing a photonic integrated circuit for multiple markers detection, which represents the functional core towards a full developed POCT device for clinical pathology applications. The photonic sensor, based on microring resonators (MRRs), is functionalized by immobilizing specific antibodies on a copolymer layer deposited on the MRR's surfaces. Surface chemical techniques were employed to analyse the surface chemical characteristics while fluorescence microscopy was involved to analyse the resulting bioreceptor surface density. The photonic sensor is characterized for the parallel detection of two biomarkers, the C-Reactive Protein (CRP) and the Creatine-Kinase-MB (CK-MB). The analyte-antibody binding curves were obtained both in buffer and in filtered un-diluted artificial saliva showing promising results both in terms of sensitivity, with limit of detection (LOD) of 103 pM for CRP and 140 pM for CK-MB, and in terms of specificity. These encouraging results let the assembly of a highly sensitive POC device for molecular diagnostics.