A biological age model based on physical examination data to predict mortality in a Chinese population.

Biological age could be reflective of an individual's health status and aging degree. Limited estimations of biological aging based on physical examination data in the Chinese population have been developed to quantify the rate of aging. We developed and validated a novel aging measure (Balanced-AGE) based on readily available physical health examination data. In this study, a repeated sub-sampling approach was applied to address the data imbalance issue, and this approach significantly improved the performance of biological age (Balanced-AGE) in predicting all-cause mortality with a 10-year time-dependent AUC of 0.908 for all-cause mortality. This mortality prediction tool was found to be effective across different subgroups by age, sex, smoking, and alcohol consumption status. Additionally, this study revealed that individuals who were underweight, smokers, or drinkers had a higher extent of age acceleration. The Balanced-AGE may serve as an effective and generally applicable tool for health assessment and management among the elderly population.

Hydrogenation of Alkynes and Olefins Catalyzed by Quaternary Ammonium Salts.

Catalytic hydrogenation of unsaturated hydrocarbons to alkenes and alkanes using molecular hydrogen is one of the most fundamental transformations in organic synthesis. While methodologies involving transition metals as catalysts in homogeneous and heterogeneous processes have been well developed, metal-free catalytic hydrogenation offers an ideal approach for future chemistry. Herein, the common and inexpensive quaternary ammonium salts are first introduced as catalysts in the catalytic hydrogenation system for the transformations from alkynes or olefins into the corresponding olefins or alkanes. Interestingly, the hydrogenation process of alkynes can be controlled to selectively produce alkenes or alkanes under different conditions. Moreover, the possible mechanism is discussed in new insights into the catalytic behavior of quaternary ammonium salts.

Asymmetric Construction of Multifunctional γ-Lactams from 1,3-Dienes and α-Ketoamides via Pd(0)-π-Lewis Base Catalysis.

A straightforward approach for the asymmetric synthesis of multifunctionalized γ-lactams, including those bearing two tetrasubstituted stereogenic centers, has been developed through a palladium-catalyzed vinylogous addition/allylic amination process between 1,3-dienes and α-ketoamides. This protocol features advantages of ready substrate availability, broad applicability, high efficiency, and excellent stereoselectivity, making it an attractive complementary tool to the previous strategies.

Tetrabutylammonium Bromide-Catalyzed Transfer Hydrogenation of Quinoxaline with HBpin as a Hydrogen Source.

A metal-free environmentally benign, simple, and efficient transfer hydrogenation process of quinoxaline has been developed using the HBpin reagent as a hydrogen source. This reaction is compatible with a variety of quinoxalines offering the desired tetrahydroquinoxalines in moderate-to-excellent yields with Bu4NBr as a noncorrosive and low-cost catalyst.

Zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source.

The zinc salt-catalyzed reduction of α-aryl imino esters, diketones and phenylacetylenes with water as hydrogen source and zinc as reductant was successfully conducted. The presented method provides a low-cost, environmentally friendly and practical preparation of α-aryl amino esters, α-hydroxyketones and phenylethylenes. By using D2O as deuterium source, the corresponding products were obtained in high efficiency with excellent deuterium incorporation rate, which gives a cheap and safe tool for access to valuable deuterium-labelled compounds.

Rhodium-catalyzed transfer hydrogenation of quinoxalines with water as a hydrogen source.

Rhodium-catalyzed transfer hydrogenation of quinoxalines with water as a hydrogen source was reported. The reaction allowed the simple preparation of tetrahydroquinoxalines under mild conditions. The deuterium-labelling experiment confirmed that water is the sole hydrogen source in the transfer hydrogenation reaction.

[Experimental Study on Migration Parameters of DEHP in PVC Infusion].

The work explored the DEHP migration parameters in PVC infusion in clinic,based on the previous research on the test model of DEHP migrated from PVC infusion,to assess the safety of PVC infusion.The leaching solution samples in different conditions were evaluated by analysis of the DEHP in leaching solution using GC-MS under simulated clinical transfusion way.The release behavior of DEHP was significantly affected by the storage time,storage temperature,surrounding temperature,dripping speed,sterilization process,volume of the leaching solution,and the property of the leaching solution.

Asymmetric Transfer Hydrogenation of Heterobicyclic Alkenes with Water as Hydrogen Source.

The asymmetric transfer hydrogenation of heterobicyclic alkenes was accomplished by using water as the sole hydrogen source. The transformation was co-catalyzed by Pd(OAc)2/Zn(OTf)2 dual catalyst with metallic zinc as reducing agent. Various azabenzonorbornadienes and oxabenzonorbornadienes were transformed to the corresponding chiral 1,2-dihydronaphthalenes by the asymmetric reductive ring-opening reactions with good to excellent enantioselectivities.

Rhodium-Catalyzed Generation of Anhydrous Hydrogen Iodide: An Effective Method for the Preparation of Iodoalkanes.

The preparation of anhydrous hydrogen iodide directly from molecular hydrogen and iodine using a rhodium catalyst is reported for the first time. The anhydrous hydrogen iodide generated was proven to be highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology not only has provided convenient access to anhydrous hydrogen iodide but also offers a practical preparation method for various iodoalkanes in excellent atom economy.

[Research on Experimental Model of Security Assessment of DEHP Migration from PVC-Tubes Medical Devices].

As we all know, DEHP is seriously harmful to human health and consequently has been acquired critical attention. DEHP is able to migrate from PVC medical devices for the non-chemically bound to PVC, thus contact with user and patient. The DEHP migration is influenced by various parameters. In order to assess the security of PVC-tubes medical devices scientifically of DEHP migration, we develop an experimental model by analyzing the parameters comprehensively and systematically, taking into account the clinical practices. For example, assessing the security of DEHP migration from infusion sets by utilizing this model.

Asymmetric transfer hydrogenation reactions of N-sulfonylimines by using alcohols as hydrogen sources.

A palladium/zinc co-catalytic system was established and successfully utilized in the asymmetric transfer hydrogenation reactions of N-sulfonylimines with alcohols as hydrogen sources. Simple alcohols such as methanol, ethanol and benzyl alcohols are all variable hydrogen sources that can reduce various N-sulfonylimines to the corresponding chiral amines with high optical purities in presence of this co-catalytic system. Primary mechanistic study revealed that the reaction may initiate with a Pd-hydride intermediate.

Rhodium-Catalyzed Asymmetric Cyclization/Addition Reactions of 1,6-Enynes and Oxa/Azabenzonorbornadienes.

A mild, efficient, and novel rhodium catalyzed asymmetric cyclization-addition domino reaction of oxa/azabenzonorbornadienes and 1,6-enynes is documented. Through the use of a [Rh(COD)2]BF4-(R)-An-SDP catalytic system, highly enantioenriched cyclization-addition products were obtained in good yields and with excellent enantioselectivities.

A novel logic gate based on liquid-crystals responding to the DNA conformational transition.

Described herein is a novel liquid crystal (LC)-based DNA logic gate constructed via employing the reorientation of LCs triggered by metal-ion-mediated DNA probe conformational changes.

Label-free liquid crystal biosensor for L-histidine: A DNAzyme-based platform for small molecule assay.

We have developed a novel DNAzyme-based liquid crystal (LC) biosensor with high sensitivity for L-histidine, which is based on L-histidine-mediated formation of DNA duplexes by cleaving DNAzyme using L-histidine, resulting in a remarkable optical signal. Firstly, an optimal amount of capture probe is bound to the glass slide, which changes the surface topology as little as possible and shows a zero-background for the sensing system. When the DNAzyme molecule is cleaved by the target, L-histidine, a partial substrate strand is produced, which in turn can hybridize with the capture probe, forming a DNA duplex. The DNA duplexes induce LC molecules to undergo a homeotropic-to-tiled transition, obtaining a remarkable optical signal. The results show that the DNAzyme-based LC biosensor is highly sensitive to L-histidine with a detection limit of 50 nM. Compared with previously reported multi-step amplified methods, this newly designed assay system for L-histidine has no amplified procedures with comparable sensitivity. This method is an unprecedented example of DNAzyme-based LC biosensor for small molecules, which has potential to offer a DNAzyme-based LC model used in various targets.

New function of exonuclease and highly sensitive label-free colorimetric DNA detection.

Enzymatic manipulation and modulation of nucleic acids are a central part of cellular function, protection, and reproduction, while rapid and accurate detection of ultralow amount of nucleic acids remains a major challenge in molecular biology research and clinic diagnosis of genetic diseases. Herein, we reported that exonuclease III can degrade the G-quadruplex structure, indicating the new exonuclease's function. Basing on the function of exonuclease III, a novel G-quadruplex-hemin DNAzyme-based colorimetric detection of tumor suppressor gene p53 was successfully developed. Although only one oligonucleotide probe was involved, the sensing strategy could suppress the optical background and achieve an efficient G-quadruplex-hemin DNAzyme-based signal amplification. Specifically, a label-free functional nucleic acid probe (called THzyme probe) was designed via introducing target DNA probe-contained hairpin structure into G-quadruplex DNAzyme. Even if this probe can fold into G-quadruplex structure in the presence of hemin very different from the double-stranded DNA, it is easily degraded by exonuclease III. Thus, no change in UV-vis absorption intensity is detected in the absence of target DNA. However, the hybridization of target DNA can protect the integrity and catalytic activity of THzyme probe, producing the DNAzyme-amplified colorimetric signal. As a result, the p53 gene was able to be detected down to 1.0 pM (final concentration in the signal-generating solution: 50.0 fM) and mismatched target DNAs were easily distinguished. It is expected that this simple sensing methodology for DNA detection can find its utility in point-of-care applications.

Electrochemical immunosensor based on Pd-Au nanoparticles supported on functionalized PDDA-MWCNT nanocomposites for aflatoxin B1 detection.

This paper reports a label-free electrochemical immunosensor for the determination of aflatoxin B1 (AFB1), which is based on a gold electrode modified by a biocompatible film of carbon nanotubes/poly(diallyldimethylammoniumchloride)/Pd-Au nanoparticles (CNTs/PDDA/Pd-Au). The nanocomposite was characterized by transmission electron microscopy and the electrochemical behavior of modified electrodes was investigated by cyclic voltammetry. The CNTs/PDDA/Pd-Au nanocomposites film showed good electron transfer ability, which ensured high sensitivity to detect AFB1 in a range from 0.05 to 25 ng mL(-1) with a detection limit of 0.03 ng mL(-1) obtained at 3σ (where σ is the standard deviation of the blank solution, n = 10). The proposed immunosensor provides a simple tool for AFB1 detection. This strategy can be extended to any other antigen detection by using the corresponding antibodies.

Multiplex protein pattern unmixing using a non-linear variable-weighted support vector machine as optimized by a particle swarm optimization algorithm.

Most of the proteins locate more than one organelle in a cell. Unmixing the localization patterns of proteins is critical for understanding the protein functions and other vital cellular processes. Herein, non-linear machine learning technique is proposed for the first time upon protein pattern unmixing. Variable-weighted support vector machine (VW-SVM) is a demonstrated robust modeling technique with flexible and rational variable selection. As optimized by a global stochastic optimization technique, particle swarm optimization (PSO) algorithm, it makes VW-SVM to be an adaptive parameter-free method for automated unmixing of protein subcellular patterns. Results obtained by pattern unmixing of a set of fluorescence microscope images of cells indicate VW-SVM as optimized by PSO is able to extract useful pattern features by optimally rescaling each variable for non-linear SVM modeling, consequently leading to improved performances in multiplex protein pattern unmixing compared with conventional SVM and other exiting pattern unmixing methods.

Split aptamer mediated endonuclease amplification for small-molecule detection.

A novel, highly sensitive split aptamer mediated endonuclease amplification strategy for the construction of aptameric sensors is reported.

Cyclodextrin supramolecular inclusion-enhanced pyrene excimer switching for time-resolved fluorescence detection of biothiols in serum.

We report here an efficient pyrene excimer signaling-based time-resolved fluorescent sensor for the measurement of biothiols (cysteine (Cys), homocysteine (Hcy), glutathione (GSH)) in human serum based on thymine-Hg(2+)-thymine (T-Hg(2+)-T) coordination chemistry and the inclusion interaction of cyclodextrin. The sensing mechanism of the approach is based on the competitive ligation of Hg(2+) ions by Hcy/Cys/GSH and T-T mismatches in a bis-pyrene-labeled DNA strand with the self-complementary 5' and 3' ends. The introduction of γ-cyclodextrin can provide cooperation for the molecular level space proximity of the two labeled pyrene molecules, moreover the hydrophobic cavity of γ-cyclodextrin can also offer protection for the pyrene dimer's emission from the quenching effect of environmental conditions and enhance the fluorescence intensity of the pyrene excimer. When the biothiols are not presented, the sensing ensemble is in the "off" state due to the long distance between the two labeled pyrene molecules resulted from the formation of a more stable T-Hg(2+)-T structure. While in the presence of biothiols, Hg(2+) interacts very strongly with thiol groups and the T-Hg(2+)-T structure is dehybridized, and then the pyrene excimer will be formed due to the self-complementary 5' and 3' ends of the DNA probe and the cooperation interaction of γ-cyclodextrin to pyrene dimer, thus resulting in switching the sensing ensemble to the "on" state. In the optimum conditions described, the linear concentration range of 1.0-100 µM with the limit of detection (LOD) of 0.36 µM for GSH was obtained. Moreover, due to the much longer lifetime of the pyrene excimer fluorescence than those of the ubiquitous endogenous fluorescent components, the time-resolved fluorescence technique has been successfully used for application in complicated biological samples.

Background eliminated signal-on electrochemical aptasensing platform for highly sensitive detection of protein.

Using platelet-derived growth factor B chain dimer (PDGF-BB) as the model target, a background current eliminated electrochemical aptameric sensing platform for highly sensitive and signal-on detection of protein is proposed in this paper. Successful fabrication of the biosensor depends on ingenious design of aptamer probe, which contains the aptamer sequence for PDGF-BB and the recognition sequence for EcoRI endonuclease. In the absence of PDGF-BB, the ferrocene labeled aptamer probe folds into a hairpin structure and forms a recognition site for EcoRI. By treatment with endonuclease, the specific and cleavable double-stranded region is cut off and redox-active ferrocene molecule is removed from the electrode surface, and almost no peak current is observed. When binding with target protein, the designed aptamer probe changes its conformation and dissociates the recognition double strand. The integrated aptamer probe is maintained when exposing to EcoRI endonuclease, resulting in obvious peak current. Therefore, a signal-on and sensitive sensing strategy for PDGF-BB detection is fabricated with eliminated background current. Under the optimized experimental conditions, a wide linear response range of 4 orders of magnitude from 20pgmL(-1) to 200ngmL(-1) is achieved with a detection limit of 10pgmL(-1). Moreover, the present aptameric platform is universal for the analysis of a broad range of target molecules of interest by changing and designing the sequence of aptamer probe.