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1.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao ; 46(2): 254-259, 2024 Apr.
Article in Chinese | MEDLINE | ID: mdl-38686723

ABSTRACT

Dopamine,a neurotransmitter ubiquitous in the body fluids,blood,and urine of mammals and humans,is responsible for regulating their functions and metabolism.The dopamine system is involved in the neurobiological mechanisms of narcolepsy in animals and humans.However,researchers have drawn different or even opposite conclusions when measuring the dopamine level in the cerebrospinal fluid of narcolepsy patients.Studies have confirmed that the occurrence of narcolepsy is related to the irreversible loss of orexins.The autoimmune reaction caused by the interactions of environmental factors with genetic factors destroys the hypothalamic orexin neurons and reduces orexin secretion,thereby lowering the level of arousal.We introduce the research progress and current status of dopamine and clinical characterization of narcolepsy by reviewing more than 40 articles published from 1982 to 2023,aiming to provide a reference for studying the relationship between the dopamine level and clinical characterization of narcolepsy and searching for the biomarkers of type 2 narcolepsy.


Subject(s)
Dopamine , Narcolepsy , Animals , Humans , Dopamine/metabolism , Intracellular Signaling Peptides and Proteins/metabolism , Narcolepsy/metabolism , Narcolepsy/diagnosis , Neuropeptides/metabolism , Orexins/metabolism , Orexins/cerebrospinal fluid
2.
Nanotechnology ; 35(27)2024 Apr 18.
Article in English | MEDLINE | ID: mdl-38522102

ABSTRACT

To obtain high-quality SiNxfilms applicable to an extensive range of processes, such as gate spacers in fin field-effect transistors (FinFETs), the self-aligned quadruple patterning process, etc, a study of plasma with higher plasma density and lower plasma damage is crucial in addition to study on novel precursors for SiNxplasma-enhanced atomic layer deposition (PEALD) processes. In this study, a novel magnetized PEALD process was developed for depositing high-quality SiNxfilms using di(isopropylamino)silane (DIPAS) and magnetized N2plasma at a low substrate temperature of 200 °C. The properties of the deposited SiNxfilms were analyzed and compared with those obtained by the PEALD process using a non-magnetized N2plasma source under the same conditions. The PEALD SiNxfilm, produced using an external magnetic field (ranging from 0 to 100 G) during the plasma exposure step, exhibited a higher growth rate (∼1 Å/cycle) due to the increased plasma density. Additionally, it showed lower surface roughness, higher film density, and enhanced wet etch resistance compared to films deposited using the PEALD process with non-magnetized plasmas. This improvement can be attributed to the higher ion flux and lower ion energy of the magnetized plasma. The electrical characteristics, such as interface trap density and breakdown voltage, were also enhanced when the magnetized plasma was used for the PEALD process. Furthermore, when SiNxfilms were deposited on high-aspect-ratio (30:1) trench patterns using the magnetized PEALD process, an improved step coverage of over 98% was achieved, in contrast to the conformality of SiNxdeposited using non-magnetized plasma. This enhancement is possibly a result of deeper radical penetration enabled by the magnetized plasma.

3.
ACS Omega ; 8(48): 45288-45300, 2023 Dec 05.
Article in English | MEDLINE | ID: mdl-38075798

ABSTRACT

Gelatin is a biocompatible biomaterial composed of a variety of amino acids that provides a possibility to regulate the interaction between cationic amino acids and neural cells. Based on our first finding that the neuron viability was improved as the lysine on the gelatin was converted into a guanidine structure, a three-dimensional (3D) gelatin hydrogel composed of gelatin and poly(allylguanidine) (PAG) was prepared to investigate neural cell behaviors. As expected, improved neuron viability, neurite outgrowth, synaptogenesis, and inhibited glial cell growth were simultaneously observed in the gelatin cross-linked with the PAG hydrogel (G-PAG) but not in the gelatin hydrogel cross-linked with poly-d-lysine (PDL) or polyethylenimine (PEI). In addition, in vivo tests also illustrated that G-PAG could provide an environment for neural culture, with improving neuron viability and neurite outgrowth. Several hydrogel characteristics-including the swelling ratio, mechanical strength, and electric property-that theoretically can influence neural cell response showed no significant difference among them. Therefore, the guanidine structure of PAG was proposed to determine the behaviors of neural cells within the gelatin-polycation hydrogels, and we proposed that the neural cell behavior is regulated by a specific gelatin-neuron relationship. The information found in this study provides a concept to design and modify gelatin-based hydrogels for neural tissue engineering applications.

4.
Nanotechnology ; 34(46)2023 Aug 29.
Article in English | MEDLINE | ID: mdl-37531942

ABSTRACT

Highly selective etching of silicon nitride over silicon oxide is one of the most important processes especially for the fabrication of vertical semiconductor devices including 3D NAND (Not And) devices. In this study, isotropic dry etching characteristics of SiNxand SiO2using ClF3/Cl2remote plasmas have been investigated. The increase of Cl2percent in ClF3/Cl2gas mixture increased etch selectivity of SiNxover SiO2while decreasing SiNxetch rate. By addition of 15% Cl to ClF3/Cl2, the etch selectivity higher than 500 could be obtained with the SiNxetch rate of ∼8 nm min-1, and the increase of Cl percent to 20% further increased the etch selectivity to higher than 1000. It was found that SiNxcan be etched through the reaction from Si-N to Si-F and Si-Cl (also from Si-Cl to Si-F) while SiO2can be etched only through the reaction from Si-O to Si-F, and which is also in extremely low reaction at room temperature. When SiNx/SiO2layer stack was etched using ClF3/Cl2(15%), extremely selective removal of SiNxlayer in the SiNx/SiO2layer stack could be obtained without noticeable etching of SiO2layer in the stack and without etch loading effect.

5.
Sci Rep ; 13(1): 10853, 2023 07 05.
Article in English | MEDLINE | ID: mdl-37407809

ABSTRACT

Impaired social abilities are characteristics of a variety of psychiatric disorders such as schizophrenia, autism spectrum disorder, and bipolar disorder. Studies consistently implicated the relationship between the anterior insular cortex (aIC) and social ability, however, how the aIC involves in processing specific subtypes of social ability was uninvestigated. We, therefore, investigated whether the absence or presence of the aIC affects the social behaviors of mice. We found that electrolytic lesions of the aIC specifically impaired mice's ability to recognize a novel stranger mouse, while the sociability of the aIC-lesioned mice was intact. Interestingly, the aIC-lesioned mice were still distinguished between a mouse that had been housed together before the aIC lesion and a novel mouse, supporting that retrieval of social recognition memory may not involve the aIC. Additional behavioral tests revealed that this specific social ability impairment induced by the aIC lesion was not due to impairment in olfaction, learning and memory, locomotion, or anxiety levels. Together our data suggest that the aIC is specifically involved in processing social recognition memory, but not necessarily involved in retrieving it.


Subject(s)
Autism Spectrum Disorder , Insular Cortex , Mice , Animals , Autism Spectrum Disorder/pathology , Memory , Recognition, Psychology , Learning , Social Behavior , Cerebral Cortex/pathology
6.
World J Clin Cases ; 11(14): 3288-3294, 2023 May 16.
Article in English | MEDLINE | ID: mdl-37274038

ABSTRACT

BACKGROUND: Hereditary spastic paraplegia (HSP) is a group of neurogenetic diseases of the corticospinal tract, accompanied by distinct spasticity and weakness of the lower extremities. Mutations in the spastic paraplegia type 4 (SPG4) gene, encoding the spastin protein, are the major cause of the disease. This study reported a Chinese family with HSP caused by a novel mutation of the SPG4 gene. CASE SUMMARY: A 44-year-old male was admitted to our hospital for long-term right lower limb weakness, leg stiffness, and unstable walking. His symptoms gradually worsened, while no obvious muscle atrophy in the lower limbs was found. Neurological examinations revealed that the muscle strength of the lower limbs was normal, and knee reflex hyperreflexia and bilateral positive Babinski signs were detected. Members of his family also had the same symptoms. Using mutation analysis, a novel heterozygous duplication mutation, c.1053dupA, p. (Gln352Thrfs*15), was identified in the SPG4 gene in this family. CONCLUSION: A Chinese family with HSP had a novel mutation of the SPG4 gene, which is autosomal dominant and inherited as pure HSP. The age of onset, sex distribution, and clinical manifestations of all existing living patients in this family were analyzed. The findings may extend the current knowledge on the existing mutations in the SPG4 gene.

7.
ACS Appl Mater Interfaces ; 15(23): 28763-28771, 2023 Jun 14.
Article in English | MEDLINE | ID: mdl-37269552

ABSTRACT

Plasma enhanced atomic layer deposition (PEALD) of silicon nitride (SiNx) using very high frequency (VHF, 162 MHz) plasma source was investigated at the process temperatures of 100, 200, and 300 °C. Two aminosilane precursors having different numbers of amino ligands, bis(tert-butylamino)silane (BTBAS) and di(sec-butylamino)silane (DSBAS), were used as Si precursors. A comparative study was also conducted to verify the effect of the number of amino ligands on the properties of SiNx film. At all process temperatures, DSBAS, having one amino ligand, performed better than BTBAS in various aspects. SiNx films deposited using DSBAS had lower surface roughness, higher film density, lower wet etch rate, improved electrical characteristics, and higher growth rate than those deposited using BTBAS. With the combination of a VHF plasma source and DSBAS with one amino ligand, the SiNx films grown at 300 °C exhibited low wet etch rates (≤2 nm/min) in a dilute HF solution (100:1 of deionized water:HF) as well as low C content below the XPS detection limit. Also, excellent step coverage close to 100% on high aspect ratio (30:1) trench structures was obtained by using VHF plasma, which could provide sufficient flux of plasma species inside the trenches in conjunction with DSBAS having fewer amino ligands than BTBAS.

8.
Mitochondrial DNA B Resour ; 8(4): 527-531, 2023.
Article in English | MEDLINE | ID: mdl-37124995

ABSTRACT

Quercus kerrii Craib 1911 (section Cyclobalanopsis) is a widespread tree species in the tropical seasonal forests of southwest China and Northern Indo-China areas. In this study, we sequenced, assembled and annotated the complete chloroplast genome of Q. kerrii. The circular genome was 160,743 bp in length and had a GC content of 36.89%. The Q. kerrii chloroplast genome has a typical quadripartite structure, including two inverted repeat regions (length, 25,825 bp; GC content, 42.76%), a large single-copy region (length, 90,196 bp; GC content, 34.74%), and a small single-copy region (length, 18,897 bp; GC content, 30.60%). Genome annotation has indicated that the Q. kerrii chloroplast genome contained 131 genes, including 86 protein-coding genes, 37 tRNA, and eight rRNA. The phylogenetic tree showed that Q. kerrii had a close relationship with Q. schottkyana Rehder & E.H.Wilson 1916.

9.
World J Clin Cases ; 11(5): 1175-1181, 2023 Feb 16.
Article in English | MEDLINE | ID: mdl-36874428

ABSTRACT

BACKGROUND: Nocardia pneumonia shares similar imaging and clinical features with pulmonary tuberculosis and lung neoplasms, but the treatment and anti-infective medication are completely different. Here, we report a case of pulmonary nocardiosis caused by Nocardia cyriacigeorgica (N. cyriacigeorgica), which was misdiagnosed as community-acquired pneumonia (CAP) with repeated fever. CASE SUMMARY: A 55-year-old female was diagnosed with community-acquired pneumonia in the local hospital because of repeated fever and chest pain for two months. After the anti-infection treatment failed in the local hospital, the patient came to our hospital for further treatment. Enhanced computed tomography showed multiple patchy, nodular and strip-shaped high-density shadows in both lungs. A routine haematological examination was performed and showed abnormalities in CD19+ B cells and CD4+ T cells. Positive acid-fast bifurcating filaments and branching gram-positive rods were observed in the bronchoalveolar lavage fluid of the patient under an oil microscope, which was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry as N. cyriacigeorgica. The patient's condition quickly improved after taking 0.96 g compound sulfamethoxazole tablets three times a day. CONCLUSION: The antibiotic treatment of Nocardia pneumonia is different from that of common CAP. Attention should be given to the pathogenic examination results of patients with recurrent fever. Nocardia pneumonia is an opportunistic infection. Patients with CD4+ T-cell deficiency should be aware of Nocardia infection.

10.
Nat Nanotechnol ; 18(5): 464-470, 2023 May.
Article in English | MEDLINE | ID: mdl-36941360

ABSTRACT

Layer transfer techniques have been extensively explored for semiconductor device fabrication as a path to reduce costs and to form heterogeneously integrated devices. These techniques entail isolating epitaxial layers from an expensive donor wafer to form freestanding membranes. However, current layer transfer processes are still low-throughput and too expensive to be commercially suitable. Here we report a high-throughput layer transfer technique that can produce multiple compound semiconductor membranes from a single wafer. We directly grow two-dimensional (2D) materials on III-N and III-V substrates using epitaxy tools, which enables a scheme comprised of multiple alternating layers of 2D materials and epilayers that can be formed by a single growth run. Each epilayer in the multistack structure is then harvested by layer-by-layer mechanical exfoliation, producing multiple freestanding membranes from a single wafer without involving time-consuming processes such as sacrificial layer etching or wafer polishing. Moreover, atomic-precision exfoliation at the 2D interface allows for the recycling of the wafers for subsequent membrane production, with the potential for greatly reducing the manufacturing cost.

11.
Article in English | WPRIM (Western Pacific) | ID: wpr-1000995

ABSTRACT

Objectives@#The purpose of this study is to understand the relationship between dental hygiene students’ empathy, interpersonal skills, and clinical practice stress, and to improve the system and skills necessary in the clinical practice process so that individuals can adapt to and perform their duties as dental hygienists in the future. @*Methods@#From the date of approval until August 30, 2022, dental hygiene students who have experienced clinical practice were conveniently extracted. The sample size was was determined with G*power 3.1.9.7 program and 190 participants were included in the final analysis. Data analysis used the IBM SPSS Statistics 26.0 program. @*Results@#Factors affecting clinical practice stress were found to be significantly related to empathic concern and personal distress, which are sub-factors of empathy, and the explanatory power was 19.7%. @*Conclusions@#Based on the above findings, in order to reduce dental hygiene students’ clinical practice stress and improve their interpersonal skills and empathy, it is necessary to provide a systematic program tailored to the student level, and further, to improve the quality of clinical practice education through industry-academia cooperation.

12.
Chinese Journal of Burns ; (6): 71-74, 2023.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-971152

ABSTRACT

On May 13, 2020, a 56-year-old man with extensive burns caused by flames and heavy metal-containing hydrothermal fluids was admitted to the General Hospital of Western Theater Command. After being admitted to the hospital, most of the burn wounds healed after treatments such as debridement, expansion, skin grafting, anti-shock, anti-infection, fluid replacement, and wound dressing change, etc. However, in the middle and late stages of treatment, the patient's burn wounds gradually showed repeated skin ulceration and inflammation. After excluding the cause of physical, bacterial infection and others, IgG4-related skin diseases was finally diagnosed by histopathological examination of tissue biopsy and concentration measurement of IgG4 in interstitial fluid, and the condition was improved after hormone treatment. This suggests that extensive burns may lead to the occurrence of autoimmune skin diseases. For the diagnosis of such diseases, it is necessary to combine clinical manifestations, serological examinations, and histopathological biopsy, etc. to avoid diagnostic pitfalls and draw correct conclusions.


Subject(s)
Male , Humans , Middle Aged , Wound Healing , Treatment Outcome , Burns/surgery , Skin Transplantation , Skin Ulcer , Metals, Heavy
13.
Asian J Pharm Sci ; 17(5): 751-766, 2022 Aug.
Article in English | MEDLINE | ID: mdl-36382309

ABSTRACT

Ferroptosis is a novel form of programmed cell death impelled by iron-dependent lipid peroxidation, which may be a potential strategy for cancer therapy. Here we demonstrated for the first time that Resveratrol (RSV), a traditional Chinese medicine (TCM) chemical monomer, could effectually inhibit the growth of colon cancer cells through the ROS-dependent ferroptosis pathway. Mechanistically, RSV evoked the increase of reactive oxygen species and lipid peroxidation in colorectal cancer cells, and eventually lead to ferroptosis. Furthermore, RSV could promote ferroptosis by downregulating the expression of the channel protein solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). To improve the delivery efficiency of RSV, a biomimetic nanocarrier was developed by coating RSV-loaded poly(ε-caprolactone)-poly(ethylene glycol) (PCL-PEG) nanoparticles with erythrocyte membrane (RSV-NPs@RBCm). The RSV-NPs@RBCm provide the possibility to escape macrophage phagocytosis and have a long circulation effect. In addition, when coupled with a tumor-penetrating peptide iRGD, which could trigger enhanced tissue penetration tumor-specifically, the delivery of RSV-NPs@RBCm into tumors would be significantly improved results from the in vivo study demonstrated an excellent treatment efficacy for CRC. Altogether, our study highlighted the therapeutic potential of RSV as a ferroptosis-inducing anticancer agent and when loaded into a biomimetic nanoplatform, it might pave the way for the application of RSV loaded nanosystems for colorectal cancer treatment.

14.
Eur J Pharmacol ; 931: 175225, 2022 Sep 15.
Article in English | MEDLINE | ID: mdl-36002038

ABSTRACT

Lung cancer is the most common cause of incidence and mortality among tumor diseases. Icariin (ICA), a potential Chinese medicine monomer, has been reported to show outstanding antitumor effects. However, the hydrophobic nature and less tumor penetration limit its potential as a topical healing agent. There are few studies report the efficacy of ICA on lung cancer, moreover, there is no biomimetic targeted delivery system in the application of ICA. Herein, we firstly develop a novel ICA bionic targeted nano-preparation, camouflaged by the tumor penetrating peptide iRGD (cRGDKGPDC), functionalized red blood cell membrane (RBCM), has the increased solubility, utilized biocompatibility, and aggravated tumor penetration of ICA. In this study, we constructed the iRGD functionalized RBCM mimetic targeted ICA-loaded nanoparticles (iRINPs) and explored the anti-tumor effect of iRINPs against lung cancer with biochemical and behavioral analysis. The results suggested that iRINPs showed improved biocompatibility and stability, and reduced phagocytic uptakes by macrophages. Besides, the modification of iRGD significantly improved the targeting ability of iRINPs. In vitro and in vivo the treatment effects and safety assays showed that iRINPs attained better therapeutic effects than ICA by inhibiting A549 cell migration, proliferation and invasion, as well as reducing side effects of ICA. Overall, we expected that the new bionic nanocarriers would be a promising nano-platform for ICA in the precise therapy of lung cancer.


Subject(s)
Antineoplastic Agents , Lung Neoplasms , Nanoparticles , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Erythrocyte Membrane , Flavonoids , Humans , Lung Neoplasms/drug therapy , Lung Neoplasms/metabolism , Nanoparticles/chemistry , Oligopeptides/pharmacology
15.
Sci Rep ; 12(1): 5703, 2022 Apr 05.
Article in English | MEDLINE | ID: mdl-35383214

ABSTRACT

Precise and selective removal of silicon nitride (SiNx) over silicon oxide (SiOy) in a oxide/nitride stack is crucial for a current three dimensional NOT-AND type flash memory fabrication process. In this study, fast and selective isotropic etching of SiNx over SiOy has been investigated using a ClF3/H2 remote plasma in an inductively coupled plasma system. The SiNx etch rate over 80 nm/min with the etch selectivity (SiNx over SiOy) of ~ 130 was observed under a ClF3 remote plasma at a room temperature. Furthermore, the addition of H2 to the ClF3 resulted in an increase of etching selectivity over 200 while lowering the etch rate of both oxide and nitride due to the reduction of F radicals in the plasma. The time dependent-etch characteristics of ClF3, ClF3 & H2 remote plasma showed little loading effect during the etching of silicon nitride on oxide/nitride stack wafer with similar etch rate with that of blank nitride wafer.

16.
Bioresour Technol ; 354: 127139, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35405215

ABSTRACT

Novel and green cholinium amino acids-based deep eutectic solvents (DESs) and their aqueous mixtures were synthesized and employed in deconstructing poplar for hemicellulose fractionation. The effects of water content in DESs on hemicellulose dissociation and structural features were comprehensively investigated, along with the reusability of DESs for treatment. The integration of water into DESs could facilitate hemicellulose fractionation, and the cholinium lysine: urea with 5 wt% water (CL: U-5) demonstrated the best performance with a hemicellulose yield of 59.2%. Further structure analysis revealed that hemicelluloses with various branching degrees and molecular weights were obtained with varying water content of DESs. Furthermore, the CL: U-5 had recyclability and reusability with a 40.5% hemicellulose yield obtained after reused three times. The novel and eco-friendly cholinium amino acids-based DESs treatment provides an effective and sustainable strategy for hemicellulose fractionation from woody biomass.


Subject(s)
Amino Acids , Deep Eutectic Solvents , Biomass , Polysaccharides , Solvents/chemistry , Water
17.
Micromachines (Basel) ; 13(2)2022 Jan 24.
Article in English | MEDLINE | ID: mdl-35208298

ABSTRACT

Low-hydrogen-containing amorphous silicon (a-Si) was deposited at a low temperature of 80 °C using a very high frequency (VHF at 162 MHz) plasma system with multi-split electrodes. Using the 162 MHz VHF plasma system, a high deposition rate of a-Si with a relatively high deposition uniformity of 6.7% could be obtained due to the formation of high-ion-density (>1011 cm-3) plasma with SiH4 and a lack of standing waves by using small multi-split electrodes. The increase in the radio frequency (RF) power decreased the hydrogen content in the deposited silicon film and, at a high RF power of 2000 W, a-Si with a low hydrogen content of 3.78% could be deposited without the need for a dehydrogenation process. The crystallization of the a-Si by ultraviolet (UV) irradiation showed that the a-Si can be crystallized with a crystallinity of 0.8 and a UV energy of 80 J without dehydrogenation. High-resolution transmission electron microscopy showed that the a-Si deposited by the VHF plasma was a very small nanocrystalline-like a-Si and the crystalline size significantly grew with the UV irradiation. We believe that the VHF (162 MHz) multi-split plasma system can be used for a low-cost low-temperature polysilicon (LTPS) process.

18.
Fertil Steril ; 117(5): 1015-1025, 2022 05.
Article in English | MEDLINE | ID: mdl-35216835

ABSTRACT

OBJECTIVE: To investigate the demographic data and karyotypes of 19,000 couples who experienced recurrent spontaneous abortion (RSA). DESIGN: A cross-sectional study of 19,000 couples. SETTING: Five hospitals. PATIENT(S): A total of 19,000 couples experiencing RSA. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Cytogenetic analysis of blood lymphocytes. RESULT(S): A total of 844 couples (4.44%) showed chromosomal aberrations in either partner. Females were more likely to have chromosomal aberrations. The mean age of females and males with chromosomal aberrations was younger than that of females and males without chromosomal aberrations. Interestingly, sex and age distribution varied significantly depending on the subtypes of chromosomal aberrations. We detected 324 balanced translocations, including 223 novel ones. They were distributed across all chromosomes; the frequency of balanced translocations decreased according to the numerical order of autosomes (strong negative correlation; r = -0.84). Individuals with balanced translocations were younger than other groups. All 58 inversions, including 25 novel ones, were detected in autosomes; the negative correlation also existed. Thirteen Robertsonian translocations, 5 deletions, and 3 duplications were detected. Six types of Turner variants, triple X mosaicism, and mosaic Down syndrome were detected in females; Klinefelter variants and mosaic XYY syndrome were detected in males. Marker chromosomes at various mosaic levels and 7 different complex chromosomal rearrangements were also observed. CONCLUSION(S): Patients who experienced RSA induced by chromosomal aberrations experienced miscarriages at a younger age. Significant correlations existed between the patients' age or sex and the subtypes of chromosomal aberrations. This study detected several chromosomal abnormalities associated with RSA, including various novel aberrations.


Subject(s)
Abortion, Habitual , Chromosome Aberrations , Abortion, Habitual/diagnosis , Abortion, Habitual/genetics , Cross-Sectional Studies , Cytogenetic Analysis , Female , Humans , Karyotyping , Male , Mosaicism , Pregnancy , Translocation, Genetic
19.
ACS Omega ; 7(4): 3254-3261, 2022 Feb 01.
Article in English | MEDLINE | ID: mdl-35128237

ABSTRACT

In this study, superabsorbent polyelectrolyte hydrogels were synthesized by cross-linking a nondegradable poly (allylamine hydrochloride) (PAH) and a recombinant protein with a specific enzymatic cleavage site. The recombinant protein was produced by E. coli with the pET-32b(+) plasmid, which is featured with the thioredoxin (Trx) gene containing a thrombin recognition site and a T7/lac hybrid promoter for high expression of recombinant protein. The swelling test shows that the composite hydrogel still maintained a high swelling ratio to 900% when 15% recombinant protein was cross-linked with PAH. The degradation test shows that such a PAH composite hydrogel could be decomposed by the addition of specific enzyme thrombin, which might lead to new biomedical applications of hydrogels needed to be decomposable by specific time not determined by the time period.

20.
Prep Biochem Biotechnol ; 52(9): 1060-1068, 2022.
Article in English | MEDLINE | ID: mdl-35098874

ABSTRACT

Here, the extraction of total flavonoids from Tremella fuciformis (TF) by aqueous two-phase extraction combined with ultrasound is presented. The extraction was optimized via a single-variable approach using the variables of mass fraction of ethanol and NaH2PO4, ultrasonication time, and TF sample amount. Response surface methodology (RSM) was then applied to determine the best conditions for extraction using the following three key parameters: ultrasonication time, ethanol mass fraction, and NaH2PO4 mass fraction. The optimum conditions were as follows: an aqueous two-phase system of ethanol/NaH2PO4, an ethanol mass fraction of 23%, a NaH2PO4 mass fraction of 27.18%, and an extraction time of 8.25 min. Under these conditions, the maximum extraction rate of total flavonoids was 0.158 mg/g. The scavenging rates for superoxide anion and hydroxyl radical, as well as the antioxidant activity of total flavonoids in TF, were studied. Total flavonoids from TF showed some scavenging ability, but the scavenging effects were lower than those of vitamin C (Vc) at the same concentrations. Nevertheless, ultrasound-assisted two-phase extraction was considered an efficient and rapid method that can be used to extract total flavonoids from TF.


Subject(s)
Antioxidants , Flavonoids , Antioxidants/pharmacology , Ascorbic Acid , Basidiomycota , Ethanol , Hydroxyl Radical , Plant Extracts , Superoxides , Water
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