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1.
Abdom Radiol (NY) ; 2024 Jul 09.
Article in English | MEDLINE | ID: mdl-38977489

ABSTRACT

BACKGROUND: Although systemic therapies are recommended for hepatocellular carcinoma (HCC) patients with main portal vein (MPV) invasion and preserved liver function, the outcome is limited. In the real-world, chemoembolization is a commonly used local treatment for advanced HCC. PURPOSE: To evaluate whether the additional chemoembolization treatment yields survival benefits compared to systemic therapy for HCC patients with MPV invasion and preserved liver function (Child-Pugh score ≤ B7) in a real-world study from multiple centers. PATIENTS AND METHODS: Between January 2020 and December 2022, 91 consecutive HCC patients with MPV invasion who received either systemic medical therapy (i.e., tyrosine kinase inhibitors (TKIs) plus anti-PD-1 immunotherapy, S group, n = 43) or in combination with chemoembolization treatment (S-T group, n = 48) from five centers were enrolled in the study. The primary outcome was overall survival (OS), and the secondary outcomes were progression-free survival (PFS) and treatment response. Adverse events (AEs) related to treatment were also recorded. Survival curves were constructed with the Kaplan-Meier method and compared using the log-rank test. RESULTS: The baseline characteristics were comparable between the two groups. The mean number of chemoembolization sessions per patient was 2.1 (range 1-3). The median OS was 10.0 months and 8.0 months in the S-T group and S group, respectively (P = 0.254). The median PFS between the two groups was similar (4.0 months vs. 4.0 months, P = 0.404). The disease control rate between the S-T and S groups were comparable (60.4% vs. 62.8%, P = 0.816). Although no chemoembolization-related deaths occurred, 13 grade 3-4 AEs occurred in the S-T group. CONCLUSIONS: The results of the real-world study demonstrated that additional chemoembolization treatment did not yield survival benefits compared to TKIs plus anti-PD-1 immunotherapy for the overall patients with advanced HCC and MPV invasion.

2.
Bioelectron Med ; 10(1): 16, 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38970083

ABSTRACT

BACKGROUND: Implantable vagus nerve stimulation is a promising approach for restoring autonomic cardiovascular functions after heart transplantation. For successful treatment a system should have multiple electrodes to deliver precise stimulation and complex neuromodulation patterns. METHODS: This paper presents an implantable multi-channel stimulation system for vagal-cardiac neuromodulation studies in swine species. The system comprises an active electrode array implant percutaneously connected to an external wearable controller. The active electrode array implant has an integrated stimulator ASIC mounted on a ceramic substrate connected to an intraneural electrode array via micro-rivet bonding. The implant is silicone encapsulated for biocompatibility and implanted lifetime. The stimulation parameters are remotely transmitted via a Bluetooth telemetry link. RESULTS: The size of the encapsulated active electrode array implant is 8 mm × 10 mm × 3 mm. The stimulator ASIC has 10-bit current amplitude resolution and 16 independent output channels, each capable of delivering up to 550 µA stimulus current and a maximum voltage of 20 V. The active electrode array implant was subjected to in vitro accelerated lifetime testing at 70 °C for 7 days with no degradation in performance. After over 2 h continuous stimulation, the surface temperature change of the implant was less than 0.5 °C. In addition, in vivo testing on the sciatic nerve of a male Göttingen minipig demonstrated that the implant could effectively elicit an EMG response that grew progressively stronger on increasing the amplitude of the stimulation. CONCLUSIONS: The multi-channel stimulator is suitable for long term implantation. It shows potential as a useful tool in vagal-cardiac neuromodulation studies in animal models for restoring autonomic cardiovascular functions after heart transplantation.

4.
Gen Thorac Cardiovasc Surg ; 72(5): 355-358, 2024 May.
Article in English | MEDLINE | ID: mdl-38261229

ABSTRACT

Acute type A aortic dissection may originate from a primary intimal tear located in the ascending aorta and often extends retrogradely into the aortic root. How to prevent bleeding in the aortic root and eliminate false lumen is very important in aortic dissection. We have developed a modified anastomotic technique that involves inverting adventitial and graft into aorta and reinforcing with a felt strip on the external border of the aortic wall. Since 2020, 45 consecutive patients with type A aortic coarctation have undergone this aortic root reconstruction procedure, to date, none have been reopened for bleeding or remnant dissection.


Subject(s)
Aortic Aneurysm, Thoracic , Aortic Dissection , Humans , Aortic Dissection/diagnostic imaging , Aortic Dissection/surgery , Aorta/surgery , Aortic Aneurysm, Thoracic/surgery
5.
Elife ; 122024 Jan 18.
Article in English | MEDLINE | ID: mdl-38236205

ABSTRACT

Breakdown of neuromuscular junctions (NMJs) is an early pathological hallmark of amyotrophic lateral sclerosis (ALS) that blocks neuromuscular transmission, leading to muscle weakness, paralysis and, ultimately, premature death. Currently, no therapies exist that can prevent progressive motor neuron degeneration, muscle denervation, or paralysis in ALS. Here, we report important advances in the development of an optogenetic, neural replacement strategy that can effectively restore innervation of severely affected skeletal muscles in the aggressive SOD1G93A mouse model of ALS, thus providing an interface to selectively control the function of targeted muscles using optical stimulation. We also identify a specific approach to confer complete survival of allogeneic replacement motor neurons. Furthermore, we demonstrate that an optical stimulation training paradigm can prevent atrophy of reinnervated muscle fibers and results in a tenfold increase in optically evoked contractile force. Together, these advances pave the way for an assistive therapy that could benefit all ALS patients.


Subject(s)
Amyotrophic Lateral Sclerosis , Animals , Mice , Humans , Amyotrophic Lateral Sclerosis/genetics , Amyotrophic Lateral Sclerosis/therapy , Optogenetics , Muscle, Skeletal , Paralysis , Cell- and Tissue-Based Therapy , Disease Models, Animal
6.
Front Immunol ; 14: 1153573, 2023.
Article in English | MEDLINE | ID: mdl-37449198

ABSTRACT

Objective: Inflammation is recognized as a contributor in the development of pulmonary arterial hypertension (PAH), and the recruitment and functional capacity of immune cells are well-orchestrated by chemokines and their receptors. This study is aimed at identification of critical chemokines in the progression of PAH via transcriptomic analysis. Methods: Differentially expressed genes (DEGs) from lungs of PAH patients were achieved compared to controls based on Gene Expression Omnibus (GEO) database. Gene set enrichment analysis (GSEA) was applied for functional annotation and pathway enrichement. The abundance of immune cells was estimated by the xCell algorithm. Weighted correlation network analysis (WGCNA) was used to construct a gene expression network, based on which a diagnostic model was generated to determine its accuracy to distinguish PAH from control subjects. Target genes were then validated in lung of hypoxia-induce pulmonary hypertension (PH) mouse model. Results: ACKR4 (atypical chemokine receptor 4) was downregulated in PAH lung tissues in multiple datasets. PAH relevant biological functions and pathways were enriched in patients with low-ACKR4 level according to GSEA enrichment analysis. Immuno-infiltration analysis revealed a negative correlation of activated dendritic cells, Th1 and macrophage infiltration with ACKR4 expression. Three gene modules were associated with PAH via WGCNA analysis, and a model for PAH diagnosis was generated using CXCL12, COL18A1 and TSHZ2, all of which correlated with ACKR4. The ACKR4 expression was also downregulated in lung tissues of our experimental PH mice compared to that of controls. Conclusions: The reduction of ACKR4 in lung tissues of human PAH based on transcriptomic data is consistent with the alteration observed in our rodent PH. The correlation with immune cell infiltration and functional annotation indicated that ACKR4 might serve as a protective immune checkpoint for PAH.


Subject(s)
Hypertension, Pulmonary , Pulmonary Arterial Hypertension , Humans , Mice , Animals , Pulmonary Arterial Hypertension/genetics , Familial Primary Pulmonary Hypertension , Hypertension, Pulmonary/genetics , Gene Expression Profiling , Lung
7.
Exp Mol Med ; 55(7): 1437-1450, 2023 07.
Article in English | MEDLINE | ID: mdl-37394591

ABSTRACT

Macrophages are immune cells crucial for host defense and homeostasis maintenance, and their dysregulation is involved in multiple pathological conditions, such as liver fibrosis. The transcriptional regulation in macrophage is indispensable for fine-tuning of macrophage functions, but the details have not been fully elucidated. Prolyl endopeptidase (PREP) is a dipeptidyl peptidase with both proteolytic and non-proteolytic functions. In this study, we found that Prep knockout significantly contributed to transcriptomic alterations in quiescent and M1/M2-polarized bone marrow-derived macrophages (BMDMs), as well as aggravated fibrosis in an experimental nonalcoholic steatohepatitis (NASH) model. Mechanistically, PREP predominantly localized to the macrophage nuclei and functioned as a transcriptional coregulator. Using CUT&Tag and co-immunoprecipitation, we found that PREP was mainly distributed in active cis-regulatory genomic regions and physically interacted with the transcription factor PU.1. Among PREP-regulated downstream genes, genes encoding profibrotic cathepsin B and D were overexpressed in BMDMs and fibrotic liver tissue. Our results indicate that PREP in macrophages functions as a transcriptional coregulator that finely tunes macrophage functions, and plays a protective role against liver fibrosis pathogenesis.


Subject(s)
Non-alcoholic Fatty Liver Disease , Prolyl Oligopeptidases , Animals , Mice , Macrophages , Fibrosis , Non-alcoholic Fatty Liver Disease/pathology , Liver Cirrhosis/pathology , Mice, Inbred C57BL
8.
IEEE Trans Biomed Circuits Syst ; 16(5): 752-765, 2022 10.
Article in English | MEDLINE | ID: mdl-36018872

ABSTRACT

This paper presents a fully implantable closed-loop device for use in freely moving rodents to investigate new treatments for motor neuron disease. The 0.18 µm CMOS integrated circuit comprises 4 stimulators, each featuring 16 channels for optical and electrical stimulation using arbitrary current waveforms at frequencies from 1.5 Hz to 50 kHz, and a bandwidth programmable front-end for neural recording. The implant uses a Qi wireless inductive link which can deliver >100 mW power at a maximum distance of 2 cm for a freely moving rodent. A backup rechargeable battery can support 10 mA continuous stimulation currents for 2.5 hours in the absence of an inductive power link. The implant is controlled by a graphic user interface with broad programmable parameters via a Bluetooth low energy bidirectional data telemetry link. The encapsulated implant is 40 mm × 20 mm × 10 mm. Measured results are presented showing the electrical performance of the electronics and the packaging method.


Subject(s)
Motor Neuron Disease , Wireless Technology , Humans , Equipment Design , Telemetry , Prostheses and Implants
9.
Front Comput Neurosci ; 16: 862126, 2022.
Article in English | MEDLINE | ID: mdl-35814346

ABSTRACT

The cochlear implantable neuromodulator provides substantial auditory perception to those with severe or profound impaired hearing. Correct electrode array positioning in the cochlea is one of the important factors for quality hearing, and misplacement may lead to additional injury to the cochlea. Visual inspection of the progress of electrode insertion is limited and mainly relies on the surgeon's tactile skills, and there is a need to detect in real-time the electrode array position in the cochlea during insertion. The available clinical measurement presently provides very limited information. Impedance measurement may be used to assist with the insertion of the electrode array. Using computational modeling of the cochlea, and its local tissue layers merging with the associated neuromodulator electrode array parameters, the impedance variations at different insertion depths and the proximities to the cochlea walls have been analyzed. In this study, an anatomical computational model of the temporal region of a patient is used to derive the relationship between impedance variations and the electrode proximity to the cochlea wall and electrode insertion depth. The aim was to examine whether the use of electrode impedance variations can be an effective marker of electrode proximity and electrode insertion depth. The proposed anatomical model simulates the quasi-static electrode impedance variations at different selected points but at considerable computation cost. A much less computationally intensive geometric model (~1/30) provided comparative impedance measurements with differences of <2%. Both use finite element analysis over the entire cross-section area of the scala tympani. It is shown that the magnitude of the impedance varies with both electrode insertion depth and electrode proximity to the adjacent anatomical layers (e.g., cochlea wall). In particular, there is a 1,400% increase when the electrode array is moved very close to the cochlea wall. This may help the surgeon to find the optimal electrode position within the scala tympani by observation of such impedance characteristics. The misplacement of the electrode array within the scala tympani may be eliminated by using the impedance variation metric during electrode array insertion if the results are validated with an experimental study.

10.
Zhongguo Zhong Yao Za Zhi ; 46(19): 4930-4935, 2021 Oct.
Article in Chinese | MEDLINE | ID: mdl-34738386

ABSTRACT

The endophytes of medicinal plants play an important role in promoting the quality formation of the host. Therefore, this paper made a review of endophytes of medicinal plant Atractylodes lancea. According to previous studies, A. lancea boasts endophytes, such as fungi, bacteria, and actinomycetes, among which the beneficial microorganisms help the growth and development of A. lancea. There is a close interaction between the volatile oil of A. lancea and endophytes. Different endophytes vary in regulating the composition and content of the volatile oil of A. lancea, which might contribute to the quality formation of A. lancea. However, the information of the endophytic flora of A. lancea obtained by traditional culture and isolation is not enough to reflect the real situation of the endophytes of A. lancea. Little is known about the endophytes of A. lancea from different chemical types and different habitats, which is not conducive to the study of the ecological relationship between A. lancea and endophytes and limits the development and utilization of the endophytes. Therefore, at the end of this paper, the authors put forward suggestions for future research on endophytes in A. lancea, including:(1)mining the core endophyte resources of A. lancea by combining high-throughput sequencing with traditional culture and isolation;(2)exploring the relationship between the diversity of endophytes and chemical types of A. lancea;(3)strengthening the application of endophytes in A. lancea cultivation, in order to facilitate the cultivation efficiency and quality of A. lancea.


Subject(s)
Atractylodes , Oils, Volatile , Plants, Medicinal , Endophytes , Fungi
11.
Materials (Basel) ; 14(21)2021 Nov 04.
Article in English | MEDLINE | ID: mdl-34772161

ABSTRACT

Magnetic nanoparticles are researched intensively not only for biomedical applications, but also for industrial applications including wastewater treatment and catalytic processes. Although these particles have been shown to have interesting surface properties in their bare form, their magnetisation remains a key feature, as it allows for magnetic separation. This makes them a promising carrier for precious materials and enables recovery via magnetic fields that can be turned on and off on demand, rather than using complex (nano)filtration strategies. However, designing a magnetic separator is by no means trivial, as the magnetic field and its gradient, the separator dimensions, the particle properties (such as size and susceptibility), and the throughput must be coordinated. This is showcased here for a simple continuous electromagnetic separator design requiring no expensive materials or equipment and facilitating continuous operation. The continuous electromagnetic separator chosen was based on a current-carrying wire in the centre of a capillary, which generated a radially symmetric magnetic field that could be described using cylindrical coordinates. The electromagnetic separator design was tested in-silico using a Lagrangian particle-tracking model accounting for hydrodynamics, magnetophoresis, as well as particle diffusion. This computational approach enabled the determination of separation efficiencies for varying particle sizes, magnetic field strengths, separator geometries, and flow rates, which provided insights into the complex interplay between these design parameters. In addition, the model identified the separator design allowing for the highest separation efficiency and determined the retention potential in both single and multiple separators in series. The work demonstrated that throughputs of ~1/4 L/h could be achieved for 250-500 nm iron oxide nanoparticle solutions, using less than 10 separator units in series.

12.
Molecules ; 26(20)2021 Oct 14.
Article in English | MEDLINE | ID: mdl-34684787

ABSTRACT

The production of α-melanocyte-stimulating hormone (α-MSH), a peptide hormone composed of 13 amino acids, is attempted by recombinant expression using E. coli as the host. To achieve this aim, a synthetic gene containing eight tandem repeats of msh gene (8msh) was designed for ribosomal synthesis of 8 α-MSH. The merit of the strategy is to diminish the peptide toxicity against the host cell and to achieve a higher production yield. Pepsin cleavage sites are introduced between the peptides for enzymatic proteolysis to obtain the monomeric peptide of α-MSH. The constructed plasmid was transformed into different strains of E. coli hosts, and E. coli XL1-Blue with gene 8msh revealed the highest yield of 8 α-MSH. Although 8 α-MSH was fractionalized in the insoluble pellets after cell lysis, pepsin cleavage was able to produce soluble α-MSH peptide, as analyzed and confirmed by mass spectrometry and peptide activity assays. The production of α-MSH was quantified using HPLC with a yield of 42.9 mg/L of LB culture. This study demonstrates the feasibility of producing α-MSH using recombinant expression of tandem repeat gene. The production procedure involves minimal post-treatment and processing and can be scaled up for industrial application.


Subject(s)
alpha-MSH/biosynthesis , alpha-MSH/genetics , Amino Acid Sequence , Animals , Antimicrobial Cationic Peptides/biosynthesis , Antimicrobial Cationic Peptides/genetics , Cell Line, Tumor , Escherichia coli/genetics , Escherichia coli/metabolism , Genes, Synthetic , Melanins/biosynthesis , Melanoma, Experimental , Mice , Pepsin A/metabolism , Recombinant Fusion Proteins/administration & dosage , Recombinant Fusion Proteins/biosynthesis , Recombinant Fusion Proteins/genetics , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , Tandem Mass Spectrometry , Tandem Repeat Sequences/genetics , alpha-MSH/administration & dosage
13.
Lab Chip ; 21(19): 3775-3783, 2021 09 28.
Article in English | MEDLINE | ID: mdl-34581389

ABSTRACT

Despite the wide usage of magnetic nanoparticles, it remains challenging to synthesise particles with properties that exploit each application's full potential. Time consuming experimental procedures and particle analysis hinder process development, which is commonly constrained to a handful of experiments without considering particle formation kinetics, reproducibility and scalability. Flow reactors are known for their potential of large-scale production and high-throughput screening of process parameters. These advantages, however, have not been utilised for magnetic nanoparticle synthesis where particle characterisation is performed, with a few exceptions, post-synthesis. To overcome this bottleneck, we developed a highly sensitive magnetometer for flow reactors to characterise magnetic nanoparticles in solution in-line and in real-time using alternating current susceptometry. This flow magnetometer enriches the flow-chemistry toolbox by facilitating continuous quality control and high-throughput screening of magnetic nanoparticle syntheses. The sensitivity required to monitor magnetic nanoparticle syntheses at the typically low concentrations (<100 mM of Fe) was achieved by comparing the signals induced in the sample and reference cell, each of which contained near-identical pairs of induction and pick-up coils. The reference cell was filled only with air, whereas the sample cell was a flow cell allowing sample solution to pass through. Balancing the flow and reference cell impedance with a newly developed electronic circuit was pivotal for the magnetometer's sensitivity. To showcase its potential, the flow magnetometer was used to monitor two iron oxide nanoparticle syntheses with well-known particle formation kinetics, i.e., co-precipitation syntheses with sodium carbonate and sodium hydroxide as base, which have been previously studied via synchrotron X-ray diffraction. The flow magnetometer facilitated batch (on-line) and flow (in-line) synthesis monitoring, providing new insights into the particle formation kinetics as well as, effect of temperature and pH. The compact lab-scale flow device presented here, opens up new possibilities for magnetic nanoparticle synthesis and manufacturing, including 1) early stage reaction characterisation 2) process monitoring and control and 3) high-throughput screening in combination with flow reactors.


Subject(s)
Magnetite Nanoparticles , Kinetics , Reproducibility of Results
14.
Front Neurosci ; 15: 681021, 2021.
Article in English | MEDLINE | ID: mdl-34366773

ABSTRACT

This article presents a versatile neurostimulation platform featuring a fully implantable multi-channel neural stimulator for chronic experimental studies with freely moving large animal models involving peripheral nerves. The implant is hermetically sealed in a ceramic enclosure and encapsulated in medical grade silicone rubber, and then underwent active tests at accelerated aging conditions at 100°C for 15 consecutive days. The stimulator microelectronics are implemented in a 0.6-µm CMOS technology, with a crosstalk reduction scheme to minimize cross-channel interference, and high-speed power and data telemetry for battery-less operation. A wearable transmitter equipped with a Bluetooth Low Energy radio link, and a custom graphical user interface provide real-time, remotely controlled stimulation. Three parallel stimulators provide independent stimulation on three channels, where each stimulator supports six stimulating sites and two return sites through multiplexing, hence the implant can facilitate stimulation at up to 36 different electrode pairs. The design of the electronics, method of hermetic packaging and electrical performance as well as in vitro testing with electrodes in saline are presented.

15.
IEEE Trans Biomed Circuits Syst ; 15(3): 464-473, 2021 06.
Article in English | MEDLINE | ID: mdl-34232889

ABSTRACT

This paper describes a simple and reproducible method for universal evaluation of the performance of electrical impedance tomography (EIT) systems using reconstructed images. To address the issues where common electrical parameters are not directly related to the quality of EIT images, based on objective full reference (FR) image quality assessment, the method provides a visually distinguishable hot colormap and two new FR metrics, the global and the more specific 'region of interest'. A passive 16 electrode EIT system using an application specific integrated circuit front-end was used to evaluate the proposed method. The measured results show, both visually and in terms of the proposed FR metrics, the impact on recorded EIT images with different design parameters and non-idealities. The paper also compares the image results of a passive electrode system with a matched 'single variable' active electrode system and demonstrates the merit of an active electrode system for noise interference. A figure of merit based on the FR metrics is proposed.


Subject(s)
Algorithms , Tomography , Electric Impedance , Electrodes , Tomography, X-Ray Computed
16.
Autism Res ; 14(11): 2424-2431, 2021 11.
Article in English | MEDLINE | ID: mdl-34288576

ABSTRACT

The Theory of Mind Inventory-2 appears to be a promising measure assessing children's theory of mind. However, a lack of evidence on its factorial structure interferes with score interpretation. To examine whether the currently-available structures of the Theory of Mind Inventory-2 are robust and replicable, confirmatory factor analysis was conducted in 242 children with autism spectrum disorder aged 3-12 years. Two possible structures were examined: the development-based structure, which reflects children's developmental stages of theory of mind (early, basic, and advanced), and the content-based structure, which represents children's social-related functions (emotion recognition, mental state term comprehension, and pragmatics). Four fit indices were adopted simultaneously to examine the model fit of both structures. We found that the development-based structure had a better model fit and was further modified. After modification, the development-based structure showed an improved model fit, but it was not completely acceptable in all fit indices. These findings suggest that the scores of the Theory of Mind Inventory-2 are more appropriate for reflecting children's developmental stages of theory of mind than the social-related functions in children with autism spectrum disorder. However, the domain scores should be cautiously interpreted because the model fits were not completely acceptable. For further revisions, ambiguous terms (e.g., "want" and "need") and confusing concepts assessed by the items (e.g., "recognize" and "understand") could be specified for a better representation of children's developmental stages of theory of mind. Moreover, further validations are needed. LAY SUMMARY: In children with autism spectrum disorder, the scores of the Theory of Mind Inventory-2 are more appropriate for indicating the developmental stages of theory of mind (early, basic, and advanced) than for indicating the social-related functions (emotion recognition, mental state term comprehension, and pragmatics). However, since the factorial validity was not completely acceptable, the domain scores should be interpreted cautiously. Moreover, further revisions and validations are warranted.


Subject(s)
Autism Spectrum Disorder , Theory of Mind , Child , Factor Analysis, Statistical , Humans
17.
Zhongguo Zhong Yao Za Zhi ; 46(8): 1910-1919, 2021 Apr.
Article in Chinese | MEDLINE | ID: mdl-33982499

ABSTRACT

The research on endophytes of medicinal plants mainly relies on the traditional culture and isolation methods. Because of their functions such as promoting host growth, improving stress resistance, promoting the accumulation of medicinal active ingredients or directly producing medicinal active ingredients, the endophytes of medicinal plants have gradually attracted wide attention. However, it was found that the strains isolated by traditional methods were not the true dominant endophytes of medicinal plants by comparing the results of traditional culture isolation with high-throughput sequencing. The blind and random nature of traditional methods leads to the lack of standards in terms of medium selection, culture time and interaction between species. On the contrary, high-throughput sequencing technology is an emerging molecular biology technology developed in recent decades. Due to its high resolution level and indepen-dent culture, it can be used for thorough analysis of the community structure and diversity of environmental microorganisms. Therefore, we proposed the strategy of using high-throughput sequencing technology to guide the traditional culture and isolation of endophytes from medicinal plants. Firstly, the endophytic structure and diversity of medicinal plants were completely clear by high-throughput sequencing technology, and the dominant endophytes of the host were unequivocal. Then according to the characteristics of each dominant endophytes design or query suitable medium for its growth to culture and isolation. Finally, the function of the isolates was studied. This method can prevent researchers from missing out on the important functional strains of the host, expand the research scope of endophytes of medicinal plants, and facilitate the in-depth excavation and utilization of endophytes of medicinal plants.


Subject(s)
Endophytes , Plants, Medicinal , Endophytes/genetics , High-Throughput Nucleotide Sequencing , Research Design
18.
ACS Appl Mater Interfaces ; 13(2): 2932-2943, 2021 Jan 20.
Article in English | MEDLINE | ID: mdl-33423476

ABSTRACT

The mechanical properties and structural design flexibility of charge-trapping polymer electrets have led to their widespread use in organic field-effect transistor (OFET) memories. For example, in the electrets of polyfluorene-based conjugated/insulating block copolymers (BCPs), the confined fiberlike polyfluorene nanostructures in the insulating polymer matrix act as effective hole-trapping sites, leading to controllable memory performance through the design of BCPs. However, few studies have reported intrinsically stretchable charge-trapping materials and their memory device applications, and a practical method to correlate the thin-film morphology of BCP electrets with their charge-trapping ability has not yet been developed. In this study, a series of new conjugated/insulating BCPs, poly(9,9-di-n-hexyl-2,7-fluorene)-block-poly(δ-decanolactone)s (PF-b-PDLx, x = 1-3), as stretchable hole-trapping materials are reported. The linear and branched PDL blocks with comparable molecular weights were used to investigate the effect of polymer architecture on morphology and device performance. Moreover, the coverage area of the polyfluorene nanofibers on the BCP films was extracted from atomic force microscopy images, which can be correlated with the trapping density of the polymer electrets. The branched PDL segments not only improve stretchability but also tailor crystallinity and phase separation of the BCPs, thus increasing their charge-trapping ability. The OFET memory device with PF-b-PDL3 as the electret layer exhibited the largest memory window (102 V) and could retain its performance at up to 100% strain. This research highlights the importance of the BCP design for developing stretchable charge-trapping materials.

19.
IEEE Trans Biomed Circuits Syst ; 15(6): 1186-1195, 2021 12.
Article in English | MEDLINE | ID: mdl-34982691

ABSTRACT

This paper presents a low power integrated multi-channel stimulator for a cardiac neuroprosthesis designed to restore the parasympathetic control after heart transplantation. The proposed stimulator is based on time-to-current conversion. It replaces the conventional current mode digital-to-analog converter (DAC) that uses tens of microamps for biasing, with a novel capacitor time-based DAC (CT-DAC) offering about 10-bit current amplitude resolution with a bias current of only 250 nA. A stimulator chip was designed in a 0.18 µm CMOS high-voltage (HV) technology. It consists of 16 independent channels, each capable of delivering up to 550 µA stimulus current with a HV output stage that can be operated up to 20 V. The stimulator chip performance was evaluated using both RC equivalent load and a microelectrode array in saline solution. It is power efficient, provides high-resolution current amplitude stimulation, and has good charge balance. The design is suitable for multi-channel neural stimulation applications.


Subject(s)
Implantable Neurostimulators , Equipment Design , Microelectrodes
20.
Ying Yong Sheng Tai Xue Bao ; 31(11): 3647-3656, 2020 Nov.
Article in Chinese | MEDLINE | ID: mdl-33300714

ABSTRACT

We examined the stability of soil aggregates in five typical plantations, i.e., Eucalyptus urophylla × E. grandis plantation, Cunninghamia lanceolata plantation, Pinus massoniana plantation, Mytilaria laosensis plantation and Castanopsis hystrix plantation, in the south subtropical China by the Elliott wet sieving and Le Bissonnais (LB) methods. The results showed that the content of water stability aggregate (WR>0.25) was more than 62.2% after wet sieving. The mean weight diameter (MWD) and geometric mean diameter (GMD) of aggregates were 1.58-3.71 mm and 0.57-2.02 mm, respectively, which were the largest in C. lanceolata plantation and the smallest in E. urophylla × E. grandis plantation. Percentage of aggregate destruction (PAD) of five kinds of plantations ranged from 4.6% to 31.5%. The transfer matrix method was used to evaluate the soil aggregates, with the aggregate stability index (ASI) following the order of C. lanceolata plantation > C. hystrix plantation > M. laosensis plantation > P. massoniana plantation > E. urophylla × E. grandis plantation. Under the three treatments of LB method, the FW treatment was the most destructive to the stability of soil aggregates, indicating that dissipation played a major role in the disintegration of soil aggregates. The WS treatment had the least damage to the aggregates. The effect of slow wetting (SW) treatment was between the fast wetting (FW) and wet stirring (WS). Both the MWD and GMD values followed the order of WS>SW>FW, which gradually decreased with the increases of soil depth. The GMD value of aggregates under FW treatment by LB method of five plantations was significantly positively correlated with ASI, MWD and GMD of wet sieving method, indicating that the traditional wet sieving method had a good correlation with FW treatment and was feasible to determine the stability of soil aggregates in the subtropical red soil. Based on the aggregate stability indices of MWD, GMD, PAD and ASI, C. lanceolata plantation was more conducive to the improvement of soil aggregation level, with more stable soil structure than the other four plantations.


Subject(s)
Cunninghamia , Pinus , Carbon/analysis , China , Soil
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