Microplastic pollution is a central issue of great concern in the current environmental field. Microplastic pollution in marine environmental media is widely reported, but the characteristics of microplastic pollution in deep sediments are rarely reported. Based on this, three sampling points were set up on the muddy coast near the Haizhou Bay, a typical aquaculture sea area, to analyze the characteristics of microplastic pollution in sediment column samples.
View Article and Find Full Text PDFThis study discusses the effects of resveratrol (RES) on the productive performance, immune function and intestinal barrier function of broiler chickens challenged with lipopolysaccharide (LPS). Two hundred and forty 1-day-old male Arbor Acres broilers were randomly divided into 4 groups of 6 replicates each, with 10 broilers per replicate. This experiment used a 2 × 2 factorial design with dietary factors (basal diets or basal diets supplemented with 400 mg/kg RES were administered from d 1 to 21) and stress factors (intraperitoneal injection of 0.
View Article and Find Full Text PDFBackground: With the increasing incidence of upper digestive tract tumors, more upper digestive tract surgeries are performed each year, and surgeons have difficulty in the postoperative management of gastrointestinal anastomotic fistula. The use of a new minimally invasive technique, endoluminal vacuum-assisted closure (E-VAC), has increased the success rate of the treatment of gastrointestinal fistula.
Methods: We present 6 cases of gastrointestinal fistula treated in our hospital in 2021: 3 cases of anastomotic fistula after esophageal cancer surgery, 2 cases of anastomotic fistula after gastric cancer surgery, and one case of esophageal rupture after trauma.
This paper proposes a synchronous demodulation technology based on sample-and-hold which shows significant advantages in the application of precision sensors. The traditional synchronous demodulation methods are discussed, and then the working principle of the proposed method is theoretically analyzed in detail. It is found that the proposed method can not only effectively suppress the harmonic components caused by the signal source but is also beneficial to improving the dynamic range of precision sensors.
View Article and Find Full Text PDFSediment samples were collected from nine sites of three sections, in the intertidal zone of Haizhou bay in July 2018. The abundance and characteristics of microplastics in the sediments (and ragworms within the sediments) were then determined to identify the source of microplastics in ragworms, and to explore the effects of ragworms on microplastics in sediment. The average abundance of microplastics in tidal flat sediments was (0.
View Article and Find Full Text PDFBundled piezoelectric motors combine several actuators to achieve high output power. However, mutual interference between the actuators leads to reduction in working efficiency. This work presents an adaptive stator that can reduce the mutual interference in bundled piezowalk motors.
View Article and Find Full Text PDFRev Sci Instrum
January 2016
A valve-type piezoelectric diaphragm pump using secondary resonant vibrator is introduced in this paper. The secondary resonant vibrator, which is mainly composed of a first vibrator and a second vibrator, is used to coordinate the frequency incompatibility between piezoelectric elements and check valves. The intermittent vibration of the first vibrator excites the resonant vibration of the second vibrator.
View Article and Find Full Text PDFA kind of multilayer ceramic capacitors (MLCCs) has been verified to have good micro-actuating properties, thus making them good candidates for nano-positioning. In this paper, we successfully employed the MLCCs as lateral scanners for a tripod scanning stage. The MLCC-based lateral scanners display hysteresis under 1.
View Article and Find Full Text PDFThe switched capacitor charge pump (SCCP) is an effective method of linearizing charges on piezoelectric actuators and therefore constitute a significant approach to nano-positioning. In this work, it was for the first time implemented in an atomic force microscope for low-distortion imaging. Experimental results showed that the image quality was improved evidently under the SCCP drive compared with that under traditional linear voltage drive.
View Article and Find Full Text PDFThis paper proposes a novel piezoelectrically driven pipette, which utilizes centrifugal force in swing motion of a vibrating tube as the driving force, to input and output liquid at first bending resonant frequency. Control circuit capable of frequency tracking is designed. Pulse volume changing with different driving voltage amplitude, driving frequency, tip size, and target reagents are studied in experiments.
View Article and Find Full Text PDFA piezoelectric element can be used separately as a sensor or an actuator. A self-sensing strategy based on a charge driver can utilize a piezoelectric element as a sensor while actuating. The strategy was proven via experiments on a cantilever vibrator using a piezoelectric plate with both sensing and actuating functions.
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
January 2012
Based on contact heat transfer, a novel method to increase power density of piezoelectric transformers is proposed. A heat transfer structure is realized by directly attaching a dissipater to the piezoelectric transformer plate. By maintaining the vibration mode of the transformer and limiting additional energy losses from the contact interface, an appropriate design can improve power density of the transformer on a large scale, resulting from effective suppression of its working temperature rise.
View Article and Find Full Text PDFRev Sci Instrum
December 2011
A static vector magnetometer based on two-dimensional (2D) vibrating coils actuated by a piezoelectric cantilever is presented. Two individual sensing coils are orthogonally fastened at the tip of cantilever and piezoelectric sheets are used to excite the cantilever bending. Due to off-axis coupler on the tip, the cantilever generates bending and twisting vibrations simultaneously on their corresponding resonant frequencies, realizing the 2D rotating vibrations of the coils.
View Article and Find Full Text PDFA major deficiency in piezoelectric actuator performance is caused by hysteresis and creep effects. Switched capacitor charge pump control was previously proved to be an effective way to reduce hysteresis. In this work, creep character of a piezoelectric stack under charge pump control is investigated and modeled.
View Article and Find Full Text PDFIEEE Trans Ultrason Ferroelectr Freq Control
April 2011
The vibration characteristics of a piezoelectric fiber actuator with helical electrodes are studied theoretically and experimentally. Its working principle indicates that the torsional, longitudinal, and tangential deformations of the fiber are coupled. A simplified dynamic model is deduced to investigate the properties of the coupled vibrations and their corresponding equivalent circuits are also provided.
View Article and Find Full Text PDFIn this study, two novel protonated cyclen and imidazolium salt-containing cationic lipids differing only in their hydrophobic region (cholesterol or diosgenin) have been designed and synthesized for gene delivery. Cationic liposomes were easily prepared from each of these lipids individually or from the mixtures of each cationic lipid and dioleoylphosphatidyl ethanolamine (DOPE). Several studies including DLS, gel retardation assay, ethidium bromide intercalation assay, and TEM demonstrated that these amphiphilic molecules are able to bind and compact DNA into nanometer particles that could be used as non-viral gene delivery agents.
View Article and Find Full Text PDFPolymeric 1,4,7,10-tetraazacyclododecanes (cyclens) using diol glycidyl ether with different chain length as bridges (5a-e) were designed and synthesized from various diols, 1,7-diprotected cyclen and epichlorohydrin. The molecular weights of the title polymers were measured by GPC with good polydispersity. Agarose gel retardation and fluorescent titration using ethidium bromide showed good DNA-binding ability of 5.
View Article and Find Full Text PDFSichuan Da Xue Xue Bao Yi Xue Ban
November 2010
Piezoelectric actuators exhibit large hysteresis between the applied voltage and their displacement. A switched capacitor charge pump is proposed to reduce hysteresis and linearize the movement of piezoelectric actuators. By pumping the same amount of charges into the piezoelectric actuator quantitatively, the actuator will be forced to change its length with constant step.
View Article and Find Full Text PDFLung cancer is one of the most highly malignant tumors, and a significant threat to human health. Lung cancer patients often exhibit tumor cell invasion and metastasis, which often render current treatments ineffective. Recently, the beneficial effects of low molecular weight heparin (LMWH) on cancer metastasis were reported in pre-clinical research studies.
View Article and Find Full Text PDFImmobilized cells of Delftia tsuruhatensis CCTCC M 205114 harboring R-amidase were applied in asymmetric hydrolysis of (R)-2, 2-dimethylcyclopropane carboxamide (R - 1) from racemic (R, S)-2, 2-dimethylcyclopropane carboxamide to accumulate (S)-2, 2-dimethylcyclopropane carboxamide (S - 1). Maximum R-amidase activity of 13.1 U/g wet cells (0.
View Article and Find Full Text PDFLinear cyclen-based polyamine (LCPA, M(w) = 7392, M(w)/M(n) = 1.19) as a novel non-viral gene vector was designed and synthesized from 1,7-diprotected 1,4,7,10-tetraazacyclododecane (cyclen), bis(beta-hydroxylethyl)amine and epichlorohydrin. Agarose gel retardation and fluorescent titration using ethidium bromide showed the good DNA-binding ability of LCPA.
View Article and Find Full Text PDFObjective: To construct a eukaryotic co-expression plasmid containing FUS1 and IL-12, and to investigate the influence of the recombinant plasmid on the cultured human lung cancer cell line A549.
Methods: RT-PCR was applied to amplify FUS1 from MRC-5 cell, the cDNA fragment of IL-12 was derived from pORF-hIL-12 by PCR, FUS1 cDNA fragment and IL-12 cDNA fragment were inserted into the multiple cloning sites of pVITRO2 to generate the eukaryotic co-expression plasmid pVITRO2-FUS1-IL-12. The recombinant plasmid was confirmed by restriction endonuclease treatment and sequenceing and transfected into A549 cells.