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1.
Adv Sci (Weinh) ; : e2401631, 2024 Apr 24.
Article En | MEDLINE | ID: mdl-38654695

Flexible and miniaturized photodetectors, offering a fast response across the ultraviolet (UV) to millimeter (MM) wave spectrum, are crucial for applications like healthcare monitoring and wearable optoelectronics. Despite their potential, developing such photodetectors faces challenges due to the lack of suitable materials and operational mechanisms. Here, the study proposes a flexible photodetector composed of a monolayer graphene connected by two distinct metal electrodes. Through the photothermoelectric effect, these asymmetric electrodes induce electron flow within the graphene channel upon electromagnetic wave illumination, resulting in a compact device with ultra-broadband and rapid photoresponse. The devices, with footprints ranging from 3 × 20 µm2 to 50 × 20 µm2, operate across a spectrum from 325 nm (UV) to 1.19 mm (MM) wave. They demonstrate a responsivity (RV) of up to 396.4 ± 5.1 mV W-1, a noise-equivalent power (NEP) of 8.6 ± 0.1 nW Hz- 0.5, and a response time as small as 0.8 ± 0.1 ms. This device facilitates direct imaging of shielded objects and material differentiation under simulated human body-wearing conditions. The straightforward device architecture, aligned with its ultra-broadband operational frequency range, is anticipated to hold significant implications for the development of miniaturized, wearable, and portable photodetectors.

2.
Biomed Chromatogr ; 38(6): e5861, 2024 Jun.
Article En | MEDLINE | ID: mdl-38501361

Fraxinus mandshurica (Oleaceae) is used as a traditional medicinal plant for the treatment of red eyes, menstrual disorders, excessive leucorrhea, chronic bronchitis and psoriasis. To perform chemical characterization of the secondary metabolites of F. mandshurica roots, bark, stems and leaves, 32 samples were collected from eight provinces in this study. A total of 64 chemical components were detected from four different parts of F. mandshurica by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Meanwhile, a total of nine secoiridoids were obtained by natural product chemical extraction, isolation and identification methods. Quantitative analysis by high-performance liquid chromatography-diode array detection-mass spectrometry showed the highest total content of secoiridoids in the bark, which is also consistent with the traditional medicinal parts. The results of methodological validation showed that the correlation coefficient (R2) values were all >0.9993, indicating a good linear range of the standard curve, while the relative standard deviations of precision, reproducibility and stability were <3%, and the spiked recoveries ranged from 98.22 to 102.27%, indicating that the experimental method was reliable and stable. In addition, fingerprinting and a heatmap were established to demonstrate the content trends of F. mandshurica more visually from different origins. Multivariate analysis, including principal component analysis and partial least squares discriminant analysis, was performed to determine the chemical characteristics of different parts of F. mandshurica, and six characteristic secoiridoids that could be used to distinguish different origins were screened. Finally, the inhibition of tyrosinase, α-glucosidase, acetylcholinesterase and pancreatic lipase activities by the nine characteristic compounds and extracts from different parts were investigated, and the results showed that they all exhibited different degrees of enzyme activity inhibition and thus have potential applications in whitening and blemish removal, hypoglycemia, anti-Alzheimer's disease and anti-obesity as a new source of natural enzyme activity inhibitors. This study establishes an identification and evaluation method applicable to phytochemistry of different origins, which is a guideline for quality control, origin evaluation and clinical application of traditional medicinal plants. This is also an unprecedented study on the identification of the chemical composition of different parts of F. mandshurica, characteristic compounds and the inhibition of enzyme activity of extracts from different parts.


Fraxinus , Plant Extracts , Fraxinus/chemistry , Chromatography, High Pressure Liquid/methods , Multivariate Analysis , Reproducibility of Results , Plant Extracts/chemistry , Linear Models , Mass Spectrometry/methods , Limit of Detection , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/analysis
3.
J Pharm Biomed Anal ; 244: 116105, 2024 Jul 15.
Article En | MEDLINE | ID: mdl-38552420

BACKGROUND: Actinidia arguta leaves (AAL) are traditionally consumed as a vegetable and as tea in folk China and Korea. Previous studies have reported the anti-diabetic effect of AAL, but its bioactive components and mechanism of action are still unclear. AIM OF THE STUDY: This study aims to identify the hypoglycemic active components of AAL by combining serum pharmacochemistry and network pharmacology and to elucidate its possible mechanism of action. METHODS: Firstly, the effective components in mice serum samples were characterized by UPLC-Q/TOF-MSE. Furthermore, based on these active ingredients, network pharmacology analysis was performed to establish an "H-C-T-P-D" interaction network and reveal possible biological mechanisms. Finally, the affinity between serum AAL components and the main proteins in the important pathways above was investigated through molecular docking analysis. RESULTS: Serum pharmacochemistry analysis showed that 69 compounds in the serum samples were identified, including 23 prototypes and 46 metabolites. The metabolic reactions mainly included deglycosylation, dehydration, hydrogenation, methylation, acetylation, glucuronidation, and sulfation. Network pharmacology analysis showed that the key components quercetin, pinoresinol diglucoside, and 5-O-trans-p-coumaroyl quinic acid butyl ester mainly acted on the core targets PTGS2, HRAS, RELA, PRKCA, and BCL2 targets and through the PI3K-Akt signaling pathway, endocrine resistance, and MAPK signaling pathway to exert a hypoglycemic effect. Likewise, molecular docking results showed that the three potential active ingredients had good binding effects on the five key targets. CONCLUSION: This study provides a basis for elucidating the pharmacodynamic substance basis of AA against T2DM and further exploring the mechanism of action.


Actinidia , Diabetes Mellitus, Type 2 , Hypoglycemic Agents , Molecular Docking Simulation , Network Pharmacology , Plant Extracts , Plant Leaves , Actinidia/chemistry , Plant Leaves/chemistry , Animals , Mice , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/chemistry , Plant Extracts/pharmacology , Plant Extracts/chemistry , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/blood , Male , Chromatography, High Pressure Liquid/methods , Signal Transduction/drug effects
4.
Molecules ; 29(2)2024 Jan 22.
Article En | MEDLINE | ID: mdl-38276619

DAPB, a new molecule including danshensu, borneol, and a mother nucleus of ACEI (Angiotensin-converting enzyme inhibitors), is being developed as an antihypertensive candidate compound. A rapid, accurate, and sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established and validated for the determination of DAPB in rat plasma. Chromatographic separation was performed on an Agilent SB-C18 column after protein precipitation by acetonitrile with a mobile phase consisting of acetonitrile and deionized water with 0.02% formic acid and 5 mM NH4F (v/v) at a flow rate of 0.2 mL/min. Quantification was performed using electrospray positive ionization mass spectrometry in the multiple reaction monitoring (MRM) mode. The method was linear over the range of 2-1000 ng/mL. The intra- and inter-day precision was within 12%, with accuracies less than 7%. Stability was within the acceptable limits under various storage and processing conditions. No apparent matrix effect was detected. The validated method was applied to the pre-clinical pharmacokinetic study of DAPB after oral administration of 30 mg/kg and intravenous administration of 6 mg/kg in rats.


Liquid Chromatography-Mass Spectrometry , Tandem Mass Spectrometry , Rats , Animals , Chromatography, Liquid/methods , Chromatography, High Pressure Liquid/methods , Tandem Mass Spectrometry/methods , Reproducibility of Results , Acetonitriles
5.
Nutrients ; 15(19)2023 Sep 23.
Article En | MEDLINE | ID: mdl-37836402

Actinidia arguta leaves (AAL) are an excellent source of bioactive components for the food industry and possess many functional properties. However, the hypoglycemic effect and mechanism of AAL remain unclear. The aim of this work was to investigate the potential hypoglycemic effect of AAL and explore its possible mechanism using 16S rRNA sequencing and serum metabolomics in diabetic mice induced by high-fat feeding in combination with streptozotocin injection. A total of 25 flavonoids from AAL were isolated and characterized, and the contents of the extract from the AAL ranged from 0.14 mg/g DW to 8.97 mg/g DW. The compound quercetin (2) had the highest content of 8.97 ± 0.09 mg/g DW, and the compound kaempferol-3-O-(2'-O-D-glucopyl)-ß-D-rutinoside (12) had the lowest content of 0.14 ± 0.01 mg/g DW. In vivo experimental studies showed that AAL reduced blood glucose and cholesterol levels, improved insulin sensitivity, and ameliorated oxidative stress and liver and kidney pathological damage. In addition, gut microbiota analysis found that AAL significantly reduced the F/B ratio, enriched the beneficial bacteria Bacteroides and Bifidobacterium, and inhibited the harmful bacteria Lactobacillus and Desulfovibrio, thereby playing an active role in intestinal imbalance. In addition, metabolomics analysis showed that AAL could improve amino acid metabolism and arachidonic acid metabolism, thereby exerting a hypoglycemic effect. This study confirmed that AAL can alleviate type 2 diabetes mellitus (T2DM) by regulating intestinal flora and interfering with related metabolic pathways, providing a scientific basis for its use as a dietary supplement and for further exploration of the mechanism of AAL against T2DM.


Actinidia , Diabetes Mellitus, Experimental , Diabetes Mellitus, Type 2 , Gastrointestinal Microbiome , Animals , Mice , Hypoglycemic Agents/pharmacology , RNA, Ribosomal, 16S , Metabolomics
6.
Nanoscale ; 15(32): 13224-13232, 2023 Aug 17.
Article En | MEDLINE | ID: mdl-37492006

Optical skyrmions have recently attracted growing interest due to their potential applications in deep-subwavelength imaging and nanometrology. While optical skyrmions have been successfully demonstrated using different field vectors, the study of their generation and control, as well as their general correlation with electromagnetic (EM) fields, is still in its infancy. Here, we theoretically propose that evanescent transverse-magnetic-polarized (TM-polarized) EM fields with rotational symmetry are actually Néel-type optical target skyrmions of the electric field vectors. Such optical target skyrmions are independent of the operation frequency and medium. Our proposal was verified by numerical simulations and real-space nano-imaging experiments performed on a graphene monolayer, where the target skyrmions could be as small as ∼100 nm in diameter. The results can therefore not only further our understanding of the formation mechanisms of EM topological textures, but also provide guidelines for the facile construction of EM skyrmions that may impact future information technologies.

7.
Food Res Int ; 163: 112228, 2023 01.
Article En | MEDLINE | ID: mdl-36596158

Actinidia arguta, an edible berry plant with high nutritional values, has been widely used in Asian countries as a food and traditional medicinal herb. The well-recognized health-promoting properties of A. arguta were associated with its bioactive components in its different botanical parts. To rapidly screen and identify chemical components and simultaneously determine the potential metabolites from different parts of A. arguta, UPLC-Q-TOF-MSE coupled with UNIFI platform and multivariate statistical analysis approach was established in this study. As a result, a total of 107 components were identified from the four different parts of A. arguta, in which 31 characteristic chemical markers were discovered among them, including 12, 8, 6, and 5 compounds from the fruits, leaves, roots, and stems, respectively. These results suggested that the combination of UPLC-Q-TOF-MSE and metabolomic analysis is a powerful method to rapidly screen characteristic markers for the quality control of A. arguta.


Actinidia , Plants, Medicinal , Actinidia/chemistry , Metabolomics , Plant Roots/chemistry , Fruit/chemistry
8.
Nutrients ; 14(19)2022 Sep 25.
Article En | MEDLINE | ID: mdl-36235633

Forty compounds were isolated and characterized from A. tenuissimum flower. Among them, twelve flavonoids showed higher α-glucosidase inhibition activities in vitro than acarbose, especially kaempferol. The molecular docking results showed that the binding of kaempferol to α-glucosidase (GAA) could reduce the hydrolysis of substrates by GAA and reduce the glucose produced by hydrolysis, thus exhibiting α-glucosidase inhibition activities. The in vivo experiment results showed that flavonoids-rich A. tenuissimum flower could decrease blood glucose and reduce lipid accumulation. The protein expression levels of RAC-alpha serine/threonine-protein kinase (AKT1), peroxisome proliferator activated receptor gamma (PPARG), and prostaglandin G/H synthase 2 (PTGS2) in liver tissue were increased. In addition, the Firmicutes/Bacteroidetes (F/B) ratio was increased, the level of gut probiotics Bifidobacterium was increased, and the levels of Enterobacteriaceae and Staphylococcus were decreased. The carbohydrate metabolism, lipid metabolism, and other pathways related to type 2 diabetes mellitus were activated. This study indicating flavonoids-rich A. tenuissimum flower could improve glycolipid metabolic disorders and inflammation in diabetic mice by modulating the protein expression and gut microbiota.


Allium , Diabetes Mellitus, Experimental , Diabetes Mellitus, Type 2 , Gastrointestinal Microbiome , Acarbose/pharmacology , Animals , Blood Glucose/metabolism , Cyclooxygenase 2 , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Experimental/microbiology , Diabetes Mellitus, Type 2/metabolism , Flavonoids/chemistry , Flowers , Glucose/metabolism , Glycolipids/pharmacology , Hypoglycemic Agents/pharmacology , Hypoglycemic Agents/therapeutic use , Kaempferols/pharmacology , Lipids/pharmacology , Mice , Molecular Docking Simulation , Network Pharmacology , PPAR gamma , Prostaglandins , Protein Kinases , Serine/pharmacology , Threonine , alpha-Glucosidases
9.
iScience ; 25(10): 105164, 2022 Oct 21.
Article En | MEDLINE | ID: mdl-36204276

As the limited carrier densities in atomic thin materials can be well controlled by electrostatic gates, p-n junctions based on two-dimensional materials in the coplanar split-gate configuration can work as photodetectors or light-emitting diodes. These coplanar gates can be fabricated in a simple one-step lithography process and are frequently used in hybrid integration with on-chip optical structures. However, the polarization-dependent responsivity of such a configuration is less explored in the near-infrared band, and a clear understanding is still missing. Here we fabricate near-infrared tunable multiple modes twisted bilayer graphene photodetector enabled by the coplanar split-gate control and confirm that the photothermoelectric effect governs the photovoltage mechanism of the p-n junction mode. Our study also elucidates that the discrepancy of the responsivities under different linear polarizations is owing to the different cavity modes and provides a valuable example for designing chip-integrated optoelectronic devices.

10.
Front Psychol ; 13: 997558, 2022.
Article En | MEDLINE | ID: mdl-36204755

The communication of mental health is an important branch of health communication, and it is also an important factor affecting people's physical and mental health. With the increasing pressure of life, people's mental health problems have huge challenges. Under the enormous pressure of economy and life, people's mental health problems are becoming increasingly prominent. This calls for attention to mental health issues. In the context of new media, knowledge about mental health can be disseminated through the Internet and mobile platforms. This approach will spread awareness of mental health prevention and basic issues. Mental health problems are also a manifestation of the lack of humanistic spirit. Excellent works related to humanistic spirit can promote the relief of mental health problems. Literature can contribute to the development of mental health problems. This research studies the communication of mental health issues in the context of new media using literary works as a carrier. At the same time, it also considers big data-related algorithms to mine the traditional characteristics of mental health problems. The research results show that new media technology can well assist the dissemination of mental health education, and literary works also contribute to the dissemination of mental health education knowledge. Collaborative filtering algorithm and atrous convolution algorithm can better predict the relevant characteristics in the process of mental health communication. For the CF algorithm, its maximum similarity index reached 0.987 when recommending mental health propagation paths using new media technology. For ACNN, the smallest prediction error is only 1.78%.

11.
Medicine (Baltimore) ; 101(28): e29384, 2022 Jul 15.
Article En | MEDLINE | ID: mdl-35839010

BACKGROUND: This study aimed to compare the clinical and radiographic outcomes of the proximal femoral nail antirotation (PFNA) and external fixation in the management of unstable intertrochanteric fractures in elderly patients. METHODS: Eighty-seven of 114 patients with unstable intertrochanteric fractures were included in this study between January 2015 and June 2019, 46 were fixed with PFNA implant and 41 with external fixator. Patient baseline characteristics, functional and radiographic results, and postoperative complication were documented and compared between the 2 groups. RESULTS: Prolonged operation duration, increased fluoroscopy time, and excess blood loss occurred in PFNA group. The functional results scores seemed higher in the PFNA than external fixation group in the first semester, and thereafter, there was no significant difference between groups. On early postoperative radiographs, better femur neck-shaft angle was acquired in the external fixators device, but the difference did not continue at final visit. The incidence rate of overall complications was 43.5% for the group PFNA and 100% for the group external fixation. CONCLUSIONS: Fewer postoperative complications occurred in PFNA than external fixator group when unstable intertrochanteric fractures were treated. Nevertheless, there was no significant difference detected in final functional and radiographic outcome between the 2 groups.


Femoral Fractures , Fracture Fixation, Intramedullary , Hip Fractures , Aged , Bone Nails , External Fixators , Femoral Fractures/surgery , Fracture Fixation , Fracture Fixation, Intramedullary/methods , Hip Fractures/surgery , Humans , Postoperative Complications/epidemiology , Retrospective Studies , Treatment Outcome
12.
Front Plant Sci ; 13: 912091, 2022.
Article En | MEDLINE | ID: mdl-35599869

Maize is an important food crop and its fungal disease has become a limiting factor to improve the yield and quality of maize. In the control of plant pathogens, commercial fungicides have no obvious effect on corn diseases due to the emergence of drug resistance. Therefore, it is of great significance to develop new fungicides with novel structure, high efficiency, and low toxicity to control maize diseases. In this paper, a series of 1,3,4-oxadiazole derivatives were designed and synthesized from benzoyl hydrazine and aromatic aldehydes through condensation and oxidation cyclization reaction. The antifungal activity of oxadiazole derivatives against three maize disease pathogens, such as Rhizoctonia solani (R. solani), Gibberella zeae (G. zeae), and Exserohilum turcicum (E. turcicum), were evaluated by mycelium growth rate method in vitro. The results indicated that most of the synthesized derivatives exhibited positive antifungal activities. Especially against E. turcicum, several compounds demonstrated significant antifungal activities and their EC 50 values were lower than positive control carbendazim. The EC 50 values of compounds 4k, 5e, and 5k were 50.48, 47.56, 32.25 µg/ml, respectively, and the carbendazim was 102.83 µg/ml. The effects of active compounds on E. turcicum microstructure were observed by scanning electron microscopy (SEM). The results showed that compounds 4k, 5e, and 5k could induce the hyphae of E. turcicum to shrink and collapse obviously. In order to elucidate the preliminary mechanism of oxadiazole derivatives, the target compounds 5e and 5k were docked with the theoretical active site of succinate dehydrogenase (SDH). Compounds 5e and 5k could bind to amino acid residues through hydrophobic contact and hydrogen bonds, which explained the possible mechanism of binding between the inhibitor and target protein. In addition, the compounds with antifungal activities had almost no cytotoxicity to MCF-7. This study showed that 1,3,4-oxadiazole derivatives were worthy for further attention as potential antifungal agents for the control of maize diseases.

13.
Opt Lett ; 47(8): 2028-2031, 2022 Apr 15.
Article En | MEDLINE | ID: mdl-35427328

Surface-enhanced Raman scattering (SERS) spectroscopy has attracted tremendous interest as a highly sensitive label-free tool to detect pollutants in aqueous environments. However, the high cost and poor reusability of conventional SERS substrates restrict their further applications in rapid and reproducible pollutant detection. Here, we report a reliable optical manipulation method to achieve rapid photothermal self-assembly of Au nanoparticles (AuNPs) in water within 30 s by a tapered optical fiber, which is utilized for highly sensitive SERS substrate preparation. The results show that the SERS substrate achieves low detection limits of 10-9 mol/L with an enhancement factor (EF) of 106 for chemical pollutants solutions, including thiram, pyrene, and rhodamine 6G. The SERS enhancement effect based on assembled AuNPs was more than 20 times that based on a gold colloid solution. As a result, the smart reversible assembly of AuNPs exhibits switchable plasmonic coupling for tuning SERS activity, which is promising for the application of SERS-based sensors and environmental pollutant detection.


Environmental Pollutants , Metal Nanoparticles , Gold/chemistry , Metal Nanoparticles/chemistry , Spectrum Analysis, Raman/methods
14.
Food Funct ; 13(7): 3931-3945, 2022 Apr 04.
Article En | MEDLINE | ID: mdl-35289350

Twenty glycoside derivatives and nine flavonoids from the leaves of Pueraria (P. thomsonii) were isolated by column chromatography and characterized by nuclear magnetic resonance spectroscopy (NMR) and high performance liquid chromatography (HPLC). The contents of twenty glycosides and nine flavonoids from the extract of P. thomsonii leaf (PL) were 173.3 mg g-1 and 134.7 mg g-1, respectively. Two flavonoids with the highest content were robinin (49.28 mg g-1) and puerarin (42.87 mg g-1). Six flavonoids, i.e. puerarin, robinin, rutin, quercetin, quercitrin, and kaempferol showed more inhibitory effects against α-glucosidase than acarbose. PL could effectively increase the level of insulin, decrease the content of fasting blood glucose, reduce lipid accumulation in plasma, ameliorate oxidative injury and inflammation, and relieve liver and kidney damage in diabetic mice. Moreover, PL could increase intestinal probiotics to improve metabolic disorders caused by diabetes and decrease the level of Clostridium celatum to relieve inflammation. This study suggested that PL or its glycoside derivatives and flavonoids regulating glycolipid metabolism and inflammation levels might have the potential to be used to control type 2 diabetes.


Diabetes Mellitus, Experimental , Diabetes Mellitus, Type 2 , Gastrointestinal Microbiome , Pueraria , Animals , Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Type 2/drug therapy , Diet, High-Fat/adverse effects , Flavonoids/chemistry , Glycosides/chemistry , Mice , Plant Extracts/chemistry , Plant Leaves/chemistry , Pueraria/chemistry , Streptozocin
15.
Opt Lett ; 46(19): 4714-4717, 2021 Oct 01.
Article En | MEDLINE | ID: mdl-34598181

The synergistic integration of optofluidic and surface enhanced Raman scattering (SERS) sensing is a new analytical technique that provides a number of unique characteristics for enhancing the sensing performance and simplifying the design of microsystems. Here, we propose a reusable optofluidic SERS sensor by integrating Au nanoisland substrate (AuNIS)-coated fiber into a microfluidic chip. Through both systematic experimental and theoretical analysis, the sensor enables efficient self-cleaning based on its optical-to-heat-hydrodynamic energy conversion property. Besides, the sensor exhibits the instrument detection limit down to 10-13mol/L and enhancement factor of 106 for Rhodamine 6G. Our optofluidic SERS sensor with such a photothermal microfluidic-assisted self-cleaning method has the advantages of portability, simple operation, and high cleaning efficiency, which will provide a new, to the best of our knowledge, concept and approach for cost-effective and reusable sensors.

17.
Opt Lett ; 45(7): 1998-2001, 2020 Apr 01.
Article En | MEDLINE | ID: mdl-32236052

Optofluidic manipulation of droplets is critical in droplet-based microfluidic systems for chemistry, biology, and medicine. Here, we reported a thermocapillary microvortices-based manipulation platform for controlling oil-in-water droplets through integrating a photothermal waveguide into a microfluidic chip. The sizes and shapes of the droplets can be controlled by adjusting optical power or positions of the water-oil interface. Here, teardrop-shaped droplets, which can encapsulate and accumulate mesoscopic matters easily, were generated when the water-oil interface and the channel boundaries approached the photothermal waveguide center simultaneously. The results showed that the thermocapillary microvortices have good controllability of droplet positions, droplet volumes, and encapsulated-particle distribution and thus it will be a powerful droplet manipulation strategy for microreactors and microcapsules.

18.
Opt Lett ; 44(7): 1868-1871, 2019 Apr 01.
Article En | MEDLINE | ID: mdl-30933168

In advanced biomedicine and microfluidics, there is a strong desire to sort and manipulate various cells and bacteria based on miniaturized microfluidic chips. Here, by integrating fiber tweezers into a T-type microfluidic channel, we report an optofluidic chip to selectively trap Escherichia coli in human blood solution based on different sizes and shapes. Furthermore, we simulate the trapping and pushing regions of other cells and bacteria, including rod-shaped bacteria, sphere-shaped bacteria, and cancer cells based on finite-difference analysis. With the advantages of controllability, low optical power, and compact construction, the strategy may be possibly applied in the fields of optical separation, cell transportation, and water quality analysis.


Cell Separation/instrumentation , Miniaturization/instrumentation , Optical Fibers , Optical Tweezers , Animals , Equipment Design , Erythrocytes/microbiology , Escherichia coli/cytology , Humans
19.
Opt Express ; 26(26): 34665-34674, 2018 Dec 24.
Article En | MEDLINE | ID: mdl-30650887

Lately, a fiber-based optical tweezer that traps and arranges the micro/nano-particles is crucial in practical applications, because such a device can trap the biological samples and drive them to the designated position in a microfluidic system or vessel without harming them. Here, we report a new type of fiber optical tweezer, which can trap and arrange erythrocytes. It is prepared by coating graphene on the cross section of a microfiber. Our results demonstrate that thermal-gradient-induced natural convection flow and thermophoresis can trap the erythrocytes under low incident power, and the optical scattering force can arrange them precisely under higher incident power. The proposed optical tweezer has high flexibility, easy fabrication, and high integration with lab-on-a-chip, and shows considerable potential for application in various fields, such as biophysics, biochemistry, and life sciences.


Erythrocytes/chemistry , Graphite/chemistry , Lab-On-A-Chip Devices , Nanostructures/chemistry , Optical Fibers , Optical Tweezers , Animals , Mice
20.
Org Biomol Chem ; 15(18): 3938-3946, 2017 May 10.
Article En | MEDLINE | ID: mdl-28436523

The coupling reaction mechanisms of the Rh(iii)-catalyzed redox-neutral C7-selective aryl C-H functionalization of indolines with alkynes and alkenes have been theoretically investigated with the aid of the density functional theory (DFT) calculations. Our calculation results indicate that the active catalyst in this system is the cationic species [Cp*Rh(OAc)]+ (2cat) instead of the neutral species Cp*Rh(OAc)2 (1cat). The origin of forming different products associated with using different coupling partners was also rationalized in detail. For the coupling reaction of N-methoxycarbamoyl-protected indoline (1a) with alkyl alkyne (4a), the electronic effect plays a dominant role and causes the six-membered ring product to be the main product. For the coupling reaction of 1a with aryl alkyne (2a), through the replacement of alkyl alkyne with aryl alkyne, the steric effect serves as a crucial factor, compared with the electronic effect, and leads to the main seven-membered ring product. For the coupling reaction of 1a with acrylate (6a), the chemoselectivity is dictated by the steric effect and electronic effect.

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