Publications by authors named "Shuxin Wang"

145 Publications

[Automatic segmentation of head and neck organs at risk based on three-dimensional U-NET deep convolutional neural network].

Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 2020 Feb;37(1):136-141

Department of Radiotherapy, First Medical Center of PLA General Hospital, BeiJing 100853, P.R.China.

The segmentation of organs at risk is an important part of radiotherapy. The current method of manual segmentation depends on the knowledge and experience of physicians, which is very time-consuming and difficult to ensure the accuracy, consistency and repeatability. Therefore, a deep convolutional neural network (DCNN) is proposed for the automatic and accurate segmentation of head and neck organs at risk. The data of 496 patients with nasopharyngeal carcinoma were reviewed. Among them, 376 cases were randomly selected for training set, 60 cases for validation set and 60 cases for test set. Using the three-dimensional (3D) U-NET DCNN, combined with two loss functions of Dice Loss and Generalized Dice Loss, the automatic segmentation neural network model for the head and neck organs at risk was trained. The evaluation parameters are Dice similarity coefficient and Jaccard distance. The average Dice Similarity coefficient of the 19 organs at risk was 0.91, and the Jaccard distance was 0.15. The results demonstrate that 3D U-NET DCNN combined with Dice Loss function can be better applied to automatic segmentation of head and neck organs at risk.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.7507/1001-5515.201903052DOI Listing
February 2020

Assembly of the Thiolated [Au Ag (S-Adm) ] Superatom Complex into a Framework Material through Direct Linkage by SbF Anions.

Angew Chem Int Ed Engl 2020 May 11;59(19):7542-7547. Epub 2020 Mar 11.

Institutes of Physical Science and Information Technology, Anhui University, JiuLong Rd, Hefei, Anhui, 230601, P. R. China.

Building framework materials with desirable properties and enhanced functionalities with nanocluster/superatom complexes as building blocks remains a challenge in the field of nanomaterials. In this study, the chiral [Au Ag (S-Adm) ] nanocluster/superatom complex (SC, in which S-Adm=1-adamantanethiol) was employed as a building block to construct the three-dimensional (3D) superatom complex inorganic framework (SCIF) materials SCIF-1 and SCIF-2 through inorganic SbF linkers. SCIF-1 is racemic due to the assembly of two SC enantiomers in a single crystal. In SCIF-2, the SC enantiomers are packed in separate crystals, thus producing larger channels and a circularly polarized luminescence (CPL) response. These two 3D SCIF materials exhibit unique sensitive photoluminescence (PL) in protic solvents. Our study provides a new pathway for creating novel open-framework materials with superatom complexes and a foundation for the further development of 3D framework materials for sensing and other applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.202000073DOI Listing
May 2020

Different Types of Ligand Exchange Induced by Au Substitution in a Maintained Nanocluster Template.

Inorg Chem 2020 Feb 16;59(3):1675-1681. Epub 2020 Jan 16.

Precisely regulating the ligand exchange on the nanocluster (NC) surface is challenging but important for fully understanding metal-ligand interactions and transformations. In this work, the homosilver nanocluster Ag(TBBM)(CHCOO) (Ag) and its Au-substitution derivative AuAg(TBBM)(CHCOO) (AuAg) have been synthesized and characterized by single-crystal X-ray crystallography (SC-XRD), nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). By precisely controlling the template metal exchange progress, the intermediate product, namely, AuAg(TBBM)(CHCOO) (AuAg-inter), was also obtained and then characterized by SC-XRD. These three nanoclusters possess a similar metallic framework, albeit some of the thiol ligands of Ag have been replaced by the introduced acetate ligands in both AuAg-inter and AuAg. Furthermore, Ag and AuAg NCs can serve as chiral amplifiers for testing the ee values of 2-chloropropionic acid, ibuprofen, naproxen, and isoleucine with high sensitivity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.inorgchem.9b02792DOI Listing
February 2020

Three-dimensional Octameric Assembly of Icosahedral M Units in [Au Ag (Dppp) (C H S) Cl ]Cl and its [Au Ag (Dppp) (C H S) ][BPh ] Derivative.

Angew Chem Int Ed Engl 2020 Mar 23;59(10):3891-3895. Epub 2020 Jan 23.

Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, 230601, P. R. China.

The high-dimensional (that is, three-dimensional (3D)) assembly of nanomaterials is an effective means of improving their properties; however, achieving this assembly at the atomic level remains challenging. Herein, we obtained a novel nanocluster, [Au Ag (Dppp) (C H S) C ]Cl (Dppp=1,3-bis(diphenylphosphino)propane) showing a 3D octameric assembly mode involving the kernel penetration of eight complete icosahedral [email protected] Au units for the first time. The atomically precise structure was determined by single-crystal X-ray diffraction, and further confirmed by thermogravimetric analysis, X-ray photoelectron spectroscopy, and electrospray ionization mass spectrometry measurements. Furthermore, ligand-induced transformation prompted the conversion of [Au Ag (Dppp) (C H S) Cl ]Cl, with complete octameric fusion into [Au Ag (Dppp) (C H S) ][BPh ] , with incomplete octameric fusion. These observations will hopefully facilitate further research on the assembly of M nanobuilding blocks.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201914350DOI Listing
March 2020

Valence self-regulation of sulfur in nanoclusters.

Sci Adv 2019 11 22;5(11):eaax7863. Epub 2019 Nov 22.

Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Anhui University, Hefei, Anhui 230601, P. R. China.

The valence self-regulation of sulfur from the "-2" valence state in thiols to the "-1" valence state in hydroxylated thiolates has been accomplished using the PtAg nanocluster as a platform-the first time that the "-1" valent sulfur has been detected as S. Two previously unknown nanoclusters, PtAg(SR) and PtAg(SR)(HO-SR) (where SR represents 2-adamantanethiol), have been synthesized and characterized-in the latter nanocluster, the presence of hydroxyl induces the valence regulation of two special S atoms from "-2" (in SR) to "-1" valence state in the HO-S(Ag)R. Because of the contrasting nature of the capping ligands in these two nanoclusters [i.e., only SR in PtAg(SR) or both SR- and HO-SR- in PtAg(SR)(HO-SR)], they exhibit differing shell architectures, even though their cores (PtAg) are in the same icosahedral configuration. Single-crystal x-ray diffraction analysis revealed their 1:1 cocrystallization, and mass spectrometry verified the presence of hydroxyls on PtAg(SR)(HO-SR).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1126/sciadv.aax7863DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6874481PMC
November 2019

Reversible nanocluster structure transformation between face-centered cubic and icosahedral isomers.

Chem Sci 2019 Oct 5;10(37):8685-8693. Epub 2019 Aug 5.

Department of Chemistry and Center for Atomic Engineering of Advanced Materials , Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials , Anhui University , Hefei , Anhui 230601 , China . Email: ; Email:

Structural transformations between isomers of nanoclusters provide a platform to tune their properties and understand the fundamental science due to their intimate structure-property correlation. Herein, we demonstrate a reversible transformation between the face-centered cubic (FCC) and icosahedral isomers of PtAg nanoclusters accomplished in the ligand-exchange processes. Ligand-exchange of 1-adamantanethiolate protected PtAg by cyclohexanethiolate could transform the FCC kernel to the icosahedral isomer. Interestingly, the icosahedral PtAg could be reversibly transformed to the FCC configuration when the cyclohexanethiolate ligand is replaced again by 1-adamantanethiolate. A combination of UV-vis absorption, mass spectrometry, photo-luminescence and X-ray absorption fine structure unambiguously identifies that the FCC-to-icosahedral structure transformation of PtAg involves two distinct stages: (i) ligand-exchange induced outmost motif transformation and (ii) abrupt innermost kernel transformation. As a result of this structural transformation, the emission wavelength of PtAg red-shifts from 672 to 720 nm, and the HOMO-LUMO energy gap reduces from 1.86 to 1.74 eV. This work presents the first example of nanocluster isomers with inter-switching configurations, and will provide new insights into manipulating the properties of nanoclusters through controllably tuning their structures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9sc02667cDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6849490PMC
October 2019

Correction to: A High-Precision and Miniature Fiber Bragg Grating-Based Force Sensor for Tissue Palpation During Minimally Invasive Surgery.

Ann Biomed Eng 2020 01;48(1):515

Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, School of Mechanical Engineering, Tianjin University, Tianjin, 300072, China.

The second equation in the section "Definition of Objective Functions and Constraints" was corrected to fix a mismatch between the PDF and HTML versions of the article.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10439-019-02413-yDOI Listing
January 2020

Acupuncture improves paralytic ileus secondary to sepsis: a case report.

Acupunct Med 2019 12 13;37(6):372-374. Epub 2019 Nov 13.

First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, Guangzhou, China.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0964528419883279DOI Listing
December 2019

A High-Precision and Miniature Fiber Bragg Grating-Based Force Sensor for Tissue Palpation During Minimally Invasive Surgery.

Ann Biomed Eng 2020 Feb 4;48(2):669-681. Epub 2019 Nov 4.

Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, School of Mechanical Engineering, Tianjin University, Tianjin, 300072, China.

This paper presents a novel Fiber Bragg Grating (FBG)-based palpation force sensor to explore tissue abnormalities during minimally invasive surgery. The proposed sensor design mainly consists of a miniature force-sensitive flexure, one tightly suspended optical fiber embedded with one FBG element and associated connectors and fixations. The flexure design has been prototyped through the configuration synthesis of Sarrus mechanism by using a rigid-body replacement method to achieve an excellent axial linear force-deformation relationship and a large measurement range. The mounted fiber has been configured at the flexure's central line with its two ends glued, and its tight suspension configuration can achieve improved resolution and sensitivity and avoid the FBG chirping failure compared to the commonly used direct FBG-pasting methods. Finite element method (FEM)-based simulation has been performed to investigate both static and dynamic performance to aid in structural design. Simulation-enabled structural optimization design has also been implemented to further improve the proposed design and the sensor's sensitivity has been increased. The optimized sensor design has been prototyped and calibrated to demonstrate an excellent linearity with a small linearity error of 0.97% and achieve a high resolution of 2.55 mN within a relatively large measurement range of 0-5 N. Dynamic force stimulation experiments, in vitro palpation implementation on a silicone phantom embedded with simulated tumors and ex vivo indentation experiments on a porcine liver have validated the effectiveness of the presented sensor design.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10439-019-02388-wDOI Listing
February 2020

Gram-Scale Preparation of Stable Hydride [email protected] (M = Au/Cu) Nanoclusters.

J Phys Chem Lett 2019 Oct 1;10(20):6124-6128. Epub 2019 Oct 1.

Key Laboratory of Structure and Functional Regulation of Hybrid Materials , Ministry of Education , Hefei 230601 , Anhui , China.

The instability of phosphine ligated copper hydride nanoclusters (CuH NCs) has largely limited their application in areas such as H storage, CO reduction, etc. In this work, the stability of CuH NCs was remarkably enhanced by improving their antioxidant capacity through two different approaches: (i) metal doping and (ii) ligand modification. Three NCs, AuCuH(PPh), CuH((-FPh)P), and AuCuH((-FPh)P), were controllably synthesized, and their structures were determined by single-crystal X-ray diffraction. The compositions of these NCs were further confirmed by electrospray ionization mass spectrometry and nuclear magnetic resonance. More importantly, we achieved gram-level production of [email protected] (M = Cu/Au) NCs protected by electron-withdrawing ligands (-FPh)P, which in turn proved their superior stability; such a large-scale preparation laid the foundation for future explorations of copper-rich NCs. This work hopes to shed light on large-scale generation of ultrastable Cu-based NCs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.jpclett.9b02297DOI Listing
October 2019

Use of 3D-Printed Heel Support Insoles Based on Arch Lift Improves Foot Pressure Distribution in Healthy People.

Med Sci Monit 2019 Sep 24;25:7175-7181. Epub 2019 Sep 24.

Orthopedic Medical Center, Second Hospital of Jilin University, Changchun, Jilin, China (mainland).

BACKGROUND 3D-printed insoles are widely used. This study was conducted to test a customized three-dimensional (3D)-printed heel support insole based on arch lift and to investigate whether the pressure distribution on the sole was improved while maintaining foot function. MATERIAL AND METHODS The design was based on a 3D plantar contour scanning modeling technique. Thirty healthy male participants walked along a 10-m track under 3 self-controlled interventions. A customized 3D-printed heel support insole based on arch lift was inserted into the socks for the experimental condition A. For condition B, a customized 3D-printed heel-supporting insole was inserted into the socks, and a standardized pre-made heel-supporting insole was inserted into the socks as a control (condition C). We used the Footscan® pressure plate to measure the plantar parameters in the forefoot contact and foot flange phases in each condition. RESULTS Compared with condition B and the control condition, the peak pressure under the heel was significantly lower in condition A (P<0.05), and the peak pressure in the midfoot region was not significantly increased (P>0.05). CONCLUSIONS The biomechanical properties of the customized 3D-printed heel support are better than those of the traditional heel support insole, especially when there is a need for an additional increase in heel height. Patients do not decrease midfoot motion function while using this customized insole.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.12659/MSM.918763DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6777389PMC
September 2019

A bio-inspired self-propelling endoscopic device for inspecting the large intestine.

Bioinspir Biomim 2019 10 11;14(6):066013. Epub 2019 Oct 11.

Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin 300072, People's Republic of China.

This article presents an inchworm-inspired, pneumatic, endoscopic device intended to navigate inside a colon. The device consists of a propulsion segment with two linear balloons and two gripper segments with four twisted balloons. The three segments can be sequentially actuated by pressurized air, which achieves a propulsive motion like an inchworm. Experimental results of the pneumatic characteristics show that the device has excellent adaptability to pipes of different diameters and good controllability of the propulsion velocity. The device is flexible enough to pass through an elbow pipe without requiring special controls, and the inspection performance of a device equipped with a camera in a flexible pipe is also presented. Moreover, the device is able to advance in an excised swine colon, which shows its great potential for applications in colonoscopy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/1748-3190/ab45c9DOI Listing
October 2019

Hand-Held Instrument with Integrated Parallel Mechanism for Active Tremor Compensation During Microsurgery.

Ann Biomed Eng 2020 Jan 17;48(1):413-425. Epub 2019 Sep 17.

Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin, 300072, China.

Physiological hand tremor seriously influences the surgical instrument's tip positioning accuracy during microsurgery. To solve this problem, hand-held active tremor compensation instruments are developed to improve tip positioning accuracy during microsurgery. This paper presents the design and performance of a new hand-held instrument that aims to stabilize hand tremors and increase accuracy in microsurgery. The key components are a three degrees of freedom (DOF) integrated parallel manipulator and a high-performance inertial measurement unit (IMU). The IMU was developed to sense the 3-DOF motion of the instrument tip. A customized filter was applied to extract specific hand tremor motion. Then, the instrument was employed to generate the reverse motion simultaneously to reduce tremor motion. Experimental results show that the tremor compensation mechanism is effective. The average RMS reduction ratio of bench test is 56.5% that is a significant tremor reduction ratio. For hand-held test, it has an average RMS reduction ratio of 41.0%. Hence, it could reduce hand tremor magnitudes by 31.7% RMS in 2-DOF.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10439-019-02358-2DOI Listing
January 2020

Light-Induced Size-Growth of Atomically Precise Nanoclusters.

Langmuir 2019 Sep 10;35(38):12350-12355. Epub 2019 Sep 10.

Department of Chemistry and Center for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials , Anhui University , Hefei , Anhui 230601 , China.

A photo-induced transformation from [Au(S--C)](TOA) to Au(S--C) nanocluster was first reported in this work. The [Au(S--C)](TOA) nanocluster is first excited to [Au(S--C)](TOA) by photons with energy higher than its ( = HOMO - LUMO energy gap), and then, the negatively charged [Au(S--C)] nanocluster was oxidized to the neutral state by transfering one electron to O. The unstable neutral cluster [Au(S--C)] obtained was decomposed into smaller nanocluster and finally reassembled into the Au(S--C) nanocluster. Time-dependent UV-vis, matrix-assisted laser desorption/ionization time of flight mass spectrometry, electron paramagnetic resonance, and electrospray ionization mass spectrometry characterizations were performed to monitor the nanocluster size transformation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.langmuir.9b01527DOI Listing
September 2019

Rational construction of a library of M nanoclusters from monometallic to tetrametallic.

Proc Natl Acad Sci U S A 2019 Sep 5;116(38):18834-18840. Epub 2019 Sep 5.

Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA 15213

Exploring intermetallic synergy has allowed a series of alloy nanoparticles with prominent chemical-physical properties to be produced. However, precise alloying based on a maintained template has long been a challenging pursuit, and little has been achieved for manipulation at the atomic level. Here, a nanosystem based on M(S-Adm)(PPh) (where S-Adm is the adamantane mercaptan and M is Ag/Cu/Au/Pt/Pd) has been established, which leads to the atomically precise operation on each site in this M template. Specifically, a library of 21 species of nanoclusters ranging from monometallic to tetrametallic constitutions has been successfully prepared step by step with in situ synthesis, target metal-exchange, and forced metal-exchange methods. More importantly, owing to the monodispersity of each nanocluster in this M library, the synergetic effects on the optical properties and stability have been mapped out. This nanocluster methodology not only provides fundamental principles to produce alloy nanoclusters with multimetallic compositions and monodispersed dopants but also provides an intriguing nanomodel that enables us to grasp the intermetallic synergy at the atomic level.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.1912719116DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6754594PMC
September 2019

Metal synergistic effect on cluster optical properties: based on Ag series nanoclusters.

Dalton Trans 2019 Sep 15;48(35):13190-13196. Epub 2019 Aug 15.

Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Anhui University, Hefei, Anhui 230601, China.

Due to their high biological stability and strong fluorescence, thiolated metal nanoclusters have shown great potential as a new generation of bio-nano-materials. However, the ambiguous mechanism of fluorescence impedes the design and synthesis of highly fluorescent nanoclusters. In this work, Ag nanocluster and its dopants were chosen as a model to study the effect of metal synergy on the optical properties. Significantly, when the valence electrons shrank to the center of the metal kernel, an enhanced fluorescence was observed, and vice versa. This finding will hopefully make a significant contribution to the property regulations of the metal nanoclusters and stimulate more excellent applications of the luminescent nanoclusters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9dt02493jDOI Listing
September 2019

Free Valence Electron Centralization Strategy for Preparing Ultrastable Nanoclusters and Their Catalytic Application.

Inorg Chem 2019 Aug 6;58(16):11000-11009. Epub 2019 Aug 6.

Department of Chemistry and Center for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials , Anhui University , Hefei 230601 , Anhui , China.

Metal nanoclusters have attracted extensive interests owing to their atomically precise structures as well as intriguing properties. However, silver nanoclusters are not as stable as their gold counterparts, impeding the practical applications of Ag nanoclusters. In this work, a strategy of free valence electron centralization was exploited to render parent Ag nanoclusters highly stable. The stability of Ag(SSR)(PPh) (SSR: benzene-1,3-dithiol) was controllably enhanced by stepwisely alloying the Ag nanocluster to AgCu(SSR)(PPh) and AuAgCu(SSR)(PPh). Specifically, the trimetallic AuAgCu is ultrastable even at 175 °C, which is close to the nanocluster decomposition temperature. The structures of AgCu and AuAgCu nanoclusters are determined by single-crystal X-ray diffraction. Furthermore, a combination of X-ray photoelectron spectroscopy measurements and density functional theory calculations demonstrates that the enhanced stability is induced by the centralization of the free valence electrons to the interior of the nanocluster. More importantly, the AuAgCu enables the multicomponent A coupling reaction at high temperatures, which remarkably shortens the catalytic reaction time from ∼5 h to 3 min. Overall, this work presents a strategy for enhancing the thermal stability of nanoclusters via centralizing the free valence electrons to the nanocluster kernels.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.inorgchem.9b01545DOI Listing
August 2019

Insight into the Geometric and Electronic Structures of Gold/Silver Superatomic Clusters Based on Icosahedron M Units and Their Alloys.

Chem Asian J 2019 Oct 3;14(19):3222-3231. Epub 2019 Sep 3.

Institutes of Physical Science and Information Technology, Department of Chemistry and Centre for Atomic Engineering, of Advanced Materials, AnHui Province, Key Laboratory of Chemistry for Inorganic/Organic, Hybrid Functionalized Materials, Anhui University, Hefei, Anhui, 230601, P.R. China.

Metal superatomic nanoclusters, with electronic structures similar to those of one certain atom, are an important type of metal clusters. Interestingly, metal clusters with metal cores composed of either icosahedral M or icosahedral assemblies always have a greater potential to become superatomic clusters. Furthermore, superatomic clusters with similar electronic compositions could possess various geometric structures, owing to differences in the shells; this provides a deeper understanding of the metal superatomic cluster and the assembly for nanomaterials. Therefore, this review focuses on the geometric and electronic structures of gold/silver superatomic clusters based on icosahedron M units and their alloys, which will facilitate the development of various applications of superatomic clusters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/asia.201900760DOI Listing
October 2019

A hand-held device with 3-DOF haptic feedback mechanism for microsurgery.

Int J Med Robot 2019 Oct 24;15(5):e2025. Epub 2019 Jul 24.

Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, Tianjin, China.

Background: The hand-held devices have the advantages of being compact and easily integrated into surgical workflow especially for microsurgery. However, one of the technical challenges of hand-held device in microsurgery is the lack of force sensing and feedback.

Methods: This paper presents a hand-held haptic device that converts imperceptible forces into human-perceptible tactile signals. It combines a force sensing tip based on fiber Bragg grating (FBG) sensors that can detect three-degrees-of-freedom (3-DOF) forces, and a haptic feedback mechanism to indicate the magnitude and direction of the forces.

Results: Experimental results demonstrate the ability to measure transverse force at the level of millinewton. User trials have been performed to validate the performance of the haptic feedback. During the phantom experiment, the transverse force was reduced with the feedback mechanism.

Conclusions: The proposed device provides important insights into the design of hand-held device incorporating real-time force sensing and haptic feedback for microsurgery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/rcs.2025DOI Listing
October 2019

Near Infrared Electrochemiluminescence of Rod-Shape 25-Atom AuAg Nanoclusters That Is Hundreds-Fold Stronger Than That of Ru(bpy) Standard.

J Am Chem Soc 2019 06 3;141(24):9603-9609. Epub 2019 Jun 3.

Department of Chemistry , Georgia State University , Atlanta , Georgia 30302 , United States.

Near infrared (near-IR) electrogenerated chemiluminescence (ECL) from rod-shape bimetallic AuAg nanoclusters is reported. With ECL standard tris(bipyridine)ruthenium(II) complex (Ru(bpy)) as reference, the self-annihilation ECL of the AuAg nanoclusters is about 10 times higher. The coreactant ECL of AuAg is about 400 times stronger than that of Ru(bpy) with 1 mM tripropylamine as coreactants. Voltammetric analysis reveals both oxidative and reductive ECLs under scanning electrode potentials. Transient ECL signals (tens of milliseconds) and decay profiles are captured by potential step experiments. An extremely strong and transient self-annihilation ECL is detected by activating LUMO and HOMO states sequentially via electrode reactions. The ECL generation pathways and mechanism are proposed based on the key anodic and cathodic activities arising from the energetics of this unique atomic-precision bimetallic nanocluster. Successes in the generation of the unprecedented strong near-IR ECL strongly support our prediction and choice of this nanocluster based on its record-high 40% quantum efficiency of near-IR photoluminescence. Correlation of the properties to the atomic/electronic structures has been a long-pursued goal particularly in the fast growing atomic-precision nanoclusters field. The mechanistic insights provided in this fundamental study could guide the design and syntheses of other nanoclusters or materials in general to achieve improved properties and further affirm the structure-function correlations. The high ECL signal in the less interfered near-infrared spectrum window offers combined merits of high-signal-low-noise/interference or high contrast for broad analytical sensing and immunoassays and other relevant applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.9b02547DOI Listing
June 2019

Total structural determination of [AuAg(Dppm)(SR)] comprising an open icosahedral AuAg core with six free valence electrons.

Chem Commun (Camb) 2019 May;55(45):6457-6460

Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Anhui University, Hefei, Anhui 230601, P. R. China.

Herein, we report the first silver-rich nanocluster containing an open icosahedral Au1Ag12 core. This nanocluster is determined to be [Au1Ag24(Dppm)3(SR)17]2+ (where Dppm is short for bis-(diphenylphosphino)methane and SR is short for cyclohexyl mercaptan) by single-crystal X-ray diffraction and electrospray ionization mass spectrometry (ESI-MS). The Au1Ag24 consists of an open icosahedral Au1Ag12, which contains six free valence electrons surrounded by a big ring motif Ag12(Dppm)3(SR)15 and two SR groups. Density Functional Theory (DFT) provided insight into the relationship between the structure and its performance.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c9cc00767aDOI Listing
May 2019

Nested Dilation Networks for Brain Tumor Segmentation Based on Magnetic Resonance Imaging.

Front Neurosci 2019 5;13:285. Epub 2019 Apr 5.

Department of Medical Imaging, Chenggong Hospital Affiliated to Xiamen University, Xiamen, China.

Brain tumors are among the most fatal cancers worldwide. Diagnosing and manually segmenting tumors are time-consuming clinical tasks, and success strongly depends on the doctor's experience. Automatic quantitative analysis and accurate segmentation of brain tumors are greatly needed for cancer diagnosis. This paper presents an advanced three-dimensional multimodal segmentation algorithm called nested dilation networks (NDNs). It is inspired by the U-Net architecture, a convolutional neural network (CNN) developed for biomedical image segmentation and is modified to achieve better performance for brain tumor segmentation. Thus, we propose residual blocks nested with dilations (RnD) in the encoding part to enrich the low-level features and use squeeze-and-excitation (SE) blocks in both the encoding and decoding parts to boost significant features. To prove the reliability of the network structure, we compare our results with those of the standard U-Net and its transmutation networks. Different loss functions are considered to cope with class imbalance problems to maximize the brain tumor segmentation results. A cascade training strategy is employed to run NDNs for coarse-to-fine tumor segmentation. This strategy decomposes the multiclass segmentation problem into three binary segmentation problems and trains each task sequentially. Various augmentation techniques are utilized to increase the diversity of the data to avoid overfitting. This approach achieves Dice similarity scores of 0.6652, 0.5880, and 0.6682 for edema, non-enhancing tumors, and enhancing tumors, respectively, in which the Dice loss is used for single-pass training. After cascade training, the Dice similarity scores rise to 0.7043, 0.5889, and 0.7206, respectively. Experiments show that the proposed deep learning algorithm outperforms other U-Net transmutation networks for brain tumor segmentation. Moreover, applying cascade training to NDNs facilitates better performance than other methods. The findings of this study provide considerable insight into the automatic and accurate segmentation of brain tumors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnins.2019.00285DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460997PMC
April 2019

A foldable manipulator with tunable stiffness based on braided structure.

J Biomed Mater Res B Appl Biomater 2020 02 22;108(2):316-325. Epub 2019 Apr 22.

Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education, Tianjin University, 135 Yaguan Road, Tianjin 300350, China.

Minimally invasive surgery (MIS) has recently seen a surge in clinical applications due to its potential benefits over open surgery. In MIS, a long manipulator is placed through a tortuous human orifice to create a channel for surgical tools and provide support when they are operated. Currently the relative large profile and low stiffness of the manipulators limit the effectiveness and accuracy of MIS. Here we propose a new foldable manipulator with tunable stiffness. The manipulator takes a braided skeleton to enable radial folding, whereas membrane is used to seal the skeleton so as to adjust stiffness through creating negative pressure. We demonstrated experimentally, numerically, and analytically that, a flexible and a rigid state were obtained, and the ratio of bending stiffness in the rigid state to that in the flexible state reached 6.85. In addition, the manipulator achieved a radial folding ratio of 1.95. The proposed manipulator shows great potential in the design of surgical robots for MIS. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B, 2019.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbm.b.34390DOI Listing
February 2020

Engineered Targeted Hyaluronic Acid-Glutathione-Stabilized Gold Nanoclusters/Graphene Oxide-5-Fluorouracil as a Smart Theranostic Platform for Stimulus-Controlled Fluorescence Imaging-Assisted Synergetic Chemo/Phototherapy.

Chem Asian J 2019 May 19;14(9):1418-1423. Epub 2019 Mar 19.

College of Chemistry and Chemical Engineering, Collaborative innovation center of modern bio-manufacture, Anhui University, Hefei, 230601, P.R. China.

A theranostic platform with integrated diagnostic and therapeutic functions as well as specific targeted and controlled combination therapy to enhance treatment efficacy is of great importance for a wide range of biomedical applications. Here, we first attempted to develop biocompatible hyaluronic acid (HA)-glutathione (GSH) conjugate stabilized gold nanoclusters (GNCs) combined with graphene oxide (GO), accompanied by loading 5-fluorouracil (5FU), as a novel theranostic platform (HG-GNCs/GO-5FU, HG refers to HA-GSH). Multifunctional HG-GNCs possessed excellent fluorescence, photosensitivity and specific targeting ability to the cancer cells while their fluorescence and singlet oxygen generation could be strongly inhibited by GO and then effectively restored by lysosomal hyaluronidase in tumor cells. The sustained and complete release of 5FU from HG-GNCs/GO could also be stimulated successively by enzymatic degradation of HA and light-induced heat effect of GO under laser irradiation so that turn-on cell imaging-assisted synergistic therapeutic strategies associated with triple enzyme/light-controlled chemo/photothermal/photodynamic therapy could be achieved at the same time, reducing greatly the side effects of materials to normal cells. Our study presents a novel strategy to combine targeting and bioimaging with triple therapies to enhance the antitumor effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/asia.201900153DOI Listing
May 2019

Uniform-loss cyclic arrayed waveguide grating router using a mode-field converter based on a slab coupler and auxiliary waveguides.

Opt Lett 2019 Jan;44(2):211-214

We designed and fabricated a silica-based 16×16 cyclic arrayed waveguide grating router (AWGR) with improved channel loss uniformity using a simple mode-field converter composed of a slab coupling region and auxiliary waveguides placed at the interface between the arrayed waveguides and the output star coupler of the AWGR. The mode-field converter transforms the fundamental Gaussian-shaped mode in the arrayed waveguides to a complex mode field which produces a flat-top far field at the image plane of the output star coupler. It does not change the overall construction of the AWGR and does not increase the device size. The experimental results show that loss non-uniformity for a 16×16 AWGR with 1.6 nm wavelength channel spacing is reduced from 3 to 0.5 dB after adapting the mode-field converter, and the crosstalk is improved by about 2 dB.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OL.44.000211DOI Listing
January 2019

Intramolecular Metal Exchange Reaction Promoted by Thiol Ligands.

Nanomaterials (Basel) 2018 Dec 19;8(12). Epub 2018 Dec 19.

Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials, Anhui University, Hefei 230601, Anhui, China.

The synthesis of an alloy nanocluster that is atomically precise is the key to understanding the metal synergy effect at the atomic level. Using the Ag₂Au(SR) nanocluster as a model, we reported a third approach for the metal exchange reaction, that is, intramolecular metal exchange. The surface adsorbed metal ions (i.e., Ag) can be exchanged with the kernel metal atoms (i.e., Au) that are promoted by thiol ligands. The exchanged gold atoms can be further stripped by the thiol ligands, and produce the AgAu(SR) nanocluster.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/nano8121070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316370PMC
December 2018

[Acceptance Test and Image Quality Assurance of MRI Simulator Equipment].

Zhongguo Yi Liao Qi Xie Za Zhi 2018 Nov;42(6):455-459

Department of Radiotherapy, PLA General Hospital, Beijing, 100853.

MRI simulator(MRI-Sim) images have unique clinical advantages with higher resolution of soft tissue and clearer visualization of tissue boundaries. Thus, the precise positioning of the tumor target area can be achieved and it is widely used in the field of radiotherapy. This article focuses on the acceptance test project and image quality assurance work of MRI-Sim equipment. The obtained ACR phantom images were used to analyze various image quality assurance indicators, and the results all reached the set standards, thereby ensuring that the obtained images meet the requirements of clinical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3969/j.issn.1671-7104.2018.06.019DOI Listing
November 2018

A Unique Pair: Ag and Ag Nanoclusters with the Same Surface but Different Cores for Structure-Property Correlation.

J Am Chem Soc 2018 Nov 9;140(46):15582-15585. Epub 2018 Nov 9.

Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials , Anhui University , Hefei , Anhui 230601 , China.

Understanding the optical properties of nanoclusters is one of the central tasks in fundamental research. In this work, two new Ag nanoclusters that have distinctly different cores but a common protecting shell are achieved, including [Ag(2,4-DMBT)(PPh)] and [Ag(2,5-DMBT)(PPh)]. Significantly, the Ag nanocluster comprises a simple cubic core of Ag, which is observed experimentally in the field of metal materials for the first time. Using the Ag and Ag nanoclusters as a unique pair, we have investigated the effect of core structure on the optical absorption properties of these nanoclusters. The compact core-shell in Ag makes the frontier orbitals highly degenerate, whereas the loose core-shell of Ag leads to much less degeneracy in the frontier orbits. Overall, this work reveals that the core packing mode plays a significant role in determining the optical properties of metal nanoclusters. The new materials with controlled crystalline phases also hold promise in other applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.8b09162DOI Listing
November 2018

Customizing the Structure, Composition, and Properties of Alloy Nanoclusters by Metal Exchange.

Acc Chem Res 2018 Nov 2;51(11):2784-2792. Epub 2018 Nov 2.

Department of Chemistry and Centre for Atomic Engineering of Advanced Materials, Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials , Anhui University , Hefei , Anhui 230601 , China.

The properties of metal materials can be greatly enriched by including various elements to generate alloys. The galvanic replacement represents a classical method for the preparation of both bulk- and nanoalloy materials. The difference of the electrochemical potential between the two metals acts as the driving force for the galvanic replacement reaction. However, this classical rule partially fails at the ultrasmall size scale, for that novel chemistry emerges by the decrease of the size of materials down to less than 3 nm due to the strong quantum effect. In this Account, we discuss an emerging topic of nanochemistry, the metal exchange in atomically precise ultrasmall (<3 nm) metal nanoparticles (or nanoclusters). The metal exchange method uses different types of metal sources (e.g., AuBrPPh or AgSR complexes) to react with templating metal nanoclusters (e.g., Au(SR)), and finally alloy nanoclusters are produced. We demonstrate that the metal exchange reaction between metal nanoclusters and metal complexes does not follow the classical metal activity sequence (i.e., Fe > Cd > Co > Ni > Pb > Cu > Hg > Ag > Pd > Pt > Au) and such metal exchange reactions in the nanocluster range is, to a large extent, related with the electron shell closing and the structural stability of nanoclusters. In the subsequent sections, we present effective control over the number, position, and distribution of the dopants. The shape and structure of the final alloy products can be tailored by recently developed metal exchange methods. More importantly, modulation and enhancement of the properties of NCs through metal exchange are realized. For example, the largely increased quantum yield and the significantly improved catalytic activity. In addition, we shall also discuss the real-time characterization of the metal exchange reaction by the combination of UV-vis absorption spectroscopy, high resolution electrospray ionization mass spectrometry (ESI-MS), matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and single crystal X-ray diffraction (SC-XRD). By controlling the charge of the templating metal nanoclusters and the different types of metal complexes, the driving force of metal exchange has been studied, which is considered to be the thermodynamics rather than the electrochemical potential. In summary, the metal exchange reactions in the ultrasmall nanocluster range are totally different compared with the case of larger-sized metal nanoparticles. Depending on this novel method, atomically precise alloy nanoclusters can be prepared by reacting the nanocluster composed of inert metal (such as Au) with complexes of high-activity metals (e.g., Cd/Hg/Cu/Ag). We anticipate that future research on the metal exchange will contribute to the fundamental understanding of reaction behavior of metal atoms in ultrasmall nanoclusters and to the design of alloy nanoclusters with enhanced properties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.accounts.8b00327DOI Listing
November 2018

Mitochondrial-Mediated Oxidative Ca/Calmodulin-Dependent Kinase II Activation Induces Early Afterdepolarizations in Guinea Pig Cardiomyocytes: An In Silico Study.

J Am Heart Assoc 2018 08;7(15):e008939

2 Department of Medicine University of Alabama at Birmingham AL.

Background Oxidative stress-mediated Ca/calmodulin-dependent protein kinase II (Ca MKII) phosphorylation of cardiac ion channels has emerged as a critical contributor to arrhythmogenesis in cardiac pathology. However, the link between mitochondrial-derived reactive oxygen species (md ROS ) and increased Ca MKII activity in the context of cardiac arrhythmias has not been fully elucidated and is difficult to establish experimentally. Methods and Results We hypothesize that pathological md ROS can cause erratic action potentials through the oxidation-dependent Ca MKII activation pathway. We further propose that Ca MKII -dependent phosphorylation of sarcolemmal slow Na channels alone is sufficient to elicit early afterdepolarizations. To test the hypotheses, we expanded our well-established guinea pig cardiomyocyte excitation- contraction coupling, mitochondrial energetics, and ROS - induced- ROS - release model by incorporating oxidative Ca MKII activation and Ca MKII -dependent Na channel phosphorylation in silico. Simulations show that md ROS mediated-Ca MKII activation elicits early afterdepolarizations by augmenting the late Na currents, which can be suppressed by blocking L-type Ca channels or Na/Ca exchangers. Interestingly, we found that oxidative Ca MKII activation-induced early afterdepolarizations are sustained even after md ROS has returned to its physiological levels. Moreover, mitochondrial-targeting antioxidant treatment can suppress the early afterdepolarizations, but only if given in an appropriate time window. Incorporating concurrent md ROS -induced ryanodine receptors activation further exacerbates the proarrhythmogenic effect of oxidative Ca MKII activation. Conclusions We conclude that oxidative Ca MKII activation-dependent Na channel phosphorylation is a critical pathway in mitochondria-mediated cardiac arrhythmogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1161/JAHA.118.008939DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6201444PMC
August 2018
-->