Wei Chen
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Pubmed
Journal: Sheng wu gong cheng xue bao = Chinese journal of biotechnology
July/21/2009
Abstract
pBR322-Red is a newly constructed recombineering plasmid, which contains a part of the pBR322 vector, a series of regulatory elements of lambda-prophage and Red recombination genes. In the beginning, we studied the best working conditions of pBR322-Red, and then modified lac operon in E. coli W3110 chromosome using the plasmid as follow: Firstly, we knockout the lacI gene using Red-mediated recombineering with overlapping single stranded DNA oligonucleotides. Secondly, we substituded the lacA and lacY genes with lacZ, a report gene, by Red-mediated linearized double strands DNA homologous recombination. Finally, we detected the expression of lacZ on these loci for the first time. The results suggested that pBR322-Red system is suitable for modifying W3110 chromosome with various recombination strategies.
Pubmed
Journal: Nanoscale
April/30/2013
Abstract
Porous BiOCl micro-flowers constructed from ultrathin nanosheets with nearly 100% {001} facets exposed were selectively prepared. The exposed {001} facets terminated with a high density of oxygen atoms and are not only favorable for the adsorption of the cationic dye RhB but also can accumulate the photogenerated electrons injected from excited RhB. These electrons can be captured by O(2) and transformed to reactive oxygen species, which possess a strong photooxidative ability to degrade the dye pollutants directly and easily. Therefore, the resultant BiOCl photocatalysts exhibit superior activity for indirect dye photosensitization degradation under visible light, with a rapid degradation rate and high photostability.
Pubmed
Journal: Sheng wu gong cheng xue bao = Chinese journal of biotechnology
September/21/2011
Abstract
Hepatitis B virus core (HBc) proteins have been used as carrier for foreign epitopes since the 1980s. They could self-assemble into icosahedral particles. Foreign epitopes could be inserted into HBc protein in various protein regions, including the N- or C-terminal and the major immunodominant region (MIR). The factors relevant in the design of HBc particles for vaccine purpose are summarized in this review.
Pubmed
Journal: Journal of colloid and interface science
May/24/2001
Abstract
Mesoporous silica with gold nanoparticles inside its pores was prepared by the soaking and ultrasound-induced reduction method. This new composite was characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), and high-resolution transmission electron microscopy (HRTEM) techniques. The results showed that nearly spherical-shaped gold nanoparticles, with mean size in diameter of 5.2 nm, are located in the pores, most of which are less than 6 nm in diameter. The ultrasonic irradiation time dependence of optical absorption for the soaked porous solid sample, as suggested by the variation in absorbance at 310 and 544 nm, indicated the reduction of Au (III) ions, and the nucleation and aggregation of gold nanoparticles within pores of mesoporous silica. Additionally, the reaction rates estimated phenomenologically by the absorbance decay at 310 nm for both the porous sample and the corresponding soaking solution presented the enhancement of the sonochemical reduction rate of Au (III) ions within pores of mesoporous silica. It is assumed that the extensive liquid-solid interfacial zones in the pores, due to the high specific surface areas and great porosity of the mesoporous solid, are the major regions where the efficient sonochemical reduction induced by the cavitation takes place. Copyright 2001 Academic Press.
Pubmed
Journal: Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi
June/13/2005
Pubmed
Journal: International journal of cancer
February/9/2012
Abstract
Interleukin-23 (IL-23)/IL-23 receptor (IL-23R) is essential for Th17 cell-mediated immune response, involved in autoimmune diseases and cancer pathogenesis. Two potentially functional genetic single nucleotide polymorphisms (SNPs; IL-23R rs6682925 T>C and rs1884444 T>G) were found to contribute to cancer susceptibility. In our study, we conducted a case-control study including 1,645 patients with esophageal cancer and 1,694 cancer-free controls in a Chinese population to assess the association between the two SNPs and the risk of esophageal cancer. We found that IL-23R rs6682925 TC/CC and rs1884444 TG/GG variant genotypes were associated with significantly increased risk of esophageal cancer [rs1884444: adjusted odds ratio (OR) = 1.16, 95% confidence intervals (CIs) =1.01-1.33; rs6682925: adjusted OR = 1.23, 95% CIs = 1.07-1.42], compared to their corresponding wild-type homozygotes. Furthermore, the increased risks associated with the two SNPs were independent from smoking and alcohol drinking status. These findings indicated that genetic variants in IL-23R may contribute to esophageal cancer risk in our Chinese population.
Pubmed
Journal: ACS nano
June/21/2012
Abstract
The self-assembly of nonplanar chloroaluminum phthalocyanine (ClAlPc) molecules as well-ordered single-molecule dipole arrays on the silicon carbide (SiC) nanomesh substrate was investigated using low temperature scanning tunneling microscopy. ClAlPc exclusively adsorbs in the center of the SiC nanomesh holes with its inherent dipole (from Cl to Al) pointing toward the substrate. The dipole can be inverted by a positively biased tip with a threshold tip voltage of 3.3 V. We deduce that the interaction between the intrinsic dipole of ClAlPc and the periodic out-of-plane component of the surface dipole on the SiC nanomesh plays a significant role in the dipole array formation.
Pubmed
Journal: Biosensors & bioelectronics
January/22/2017
Abstract
Charge separation is crucial for increasing the performances of semiconductor-based materials in many photoactive applications. In this paper, we designed novel nanocomposites consisting of TiO2 nanocrystals, Ag nanoparticles (NPs) and nitrogen doped graphene (NGR) via a facile one-pot hydrothermal route. The as-prepared ternary nanocomposites exhibited enhanced photoelectrochemical (PEC) performances owing to the introduction of Ag NPs and NGR, which increase the excitons' lifetime and improve the charge transfer. In particular, it is shown by means of the transient-state surface photocurrent responses that the photocurrent intensity of the as-fabricated composites exhibited 18.2 times higher than that of pristine TiO2. Based on the robust photocurrent signal, a new kind of "on-off-on" PEC aptasensor was established with the assistance of Pb(2+) aptamer, which integrates the advantages of low background signal and high sensitivity. Under optimal conditions, a wide linear response for Pb(2+) detection was obtained from 1pM to 5nM as well as a detection limit down to 0.3pM. With its simplicity, selectivity, and sensitivity, this proposed strategy shows great promise for Pb(2+) detection in food and environment analysis.
Pubmed
Journal: Journal of medicinal chemistry
April/11/2016
Abstract
Human clinical studies conducted with LCI699 established aldosterone synthase (CYP11B2) inhibition as a promising novel mechanism to lower arterial blood pressure. However, LCI699's low CYP11B1/CYP11B2 selectivity resulted in blunting of adrenocorticotropic hormone-stimulated cortisol secretion. This property of LCI699 prompted its development in Cushing's disease, but limited more extensive clinical studies in hypertensive populations, and provided an impetus for the search for cortisol-sparing CYP11B2 inhibitors. This paper summarizes the discovery, pharmacokinetics, and pharmacodynamic data in preclinical species and human subjects of the selective CYP11B2 inhibitor 8.
Pubmed
Journal: Applied microbiology and biotechnology
April/29/2012
Abstract
Lactobacillus casei has traditionally been recognized as a probiotic and frequently used as an adjunct culture in fermented dairy products, where acid stress is an environmental condition commonly encountered. In the present study, we carried out a comparative physiological and proteomic study to investigate lactic-acid-induced alterations in Lactobacillus casei Zhang (WT) and its acid-resistant mutant. Analysis of the physiological data showed that the mutant exhibited 33.8% higher glucose phosphoenolpyruvate:sugar phosphotransferase system activity and lower glycolytic pH compared with the WT under acidic conditions. In addition, significant differences were detected in both cells during acid stress between intracellular physiological state, including intracellular pH, H(+)-ATPase activity, and intracellular ATP pool. Comparison of the proteomic data based on 2D-DIGE and i-TRAQ indicated that acid stress invoked a global change in both strains. The mutant protected the cells against acid damage by regulating the expression of key proteins involved in cellular metabolism, DNA replication, RNA synthesis, translation, and some chaperones. Proteome results were validated by Lactobacillus casei displaying higher intracellular aspartate and arginine levels, and the survival at pH 3.3 was improved 1.36- and 2.10-fold by the addition of 50-mM aspartate and arginine, respectively. To our knowledge, this is the first demonstration that aspartate may be involved in acid tolerance in Lactobacillus casei. Results presented here may help us understand acid resistance mechanisms and help formulate new strategies to enhance the industrial applications of this species.
Pubmed
Journal: Oncology reports
June/17/2009
Abstract
Hepatitis B virus has been linked to the pathogenesis and carcinogenesis of hepatocellular carcinoma. Components of viruses have been identified within pathological specimens of hepatocellular carcinoma tissue. We characterized the in vitro response of human normal liver cells (L-02 cells) to components of infectious agents related to toll-like receptors. Immortalized human normal liver cells (L-02 cells) exhibited increased proliferation in response to exposure to CpG DNA. This molecule is a well-characterized surrogate for DNA viruses, which are common in the liver. Our experiments show that L-02 cells and some hepatoma cell lines such as HepG2, HuH7, Hep3B, express TLR 9 (CpG-specific). CpG DNA, HBV DNA, DNA of HBV middle envelope protein (MP) containing a number of CpG, supernatant of HepG2.2.15 (HepG2 cells transfected HBV) excreting HBV DNA and extraction of nucleic acids from HepG2.2.15 supernatant can all activate NF-kappaB. In addition, L-02 cells were less susceptible to TNF-alpha-induced apoptosis as measured by Annexin V-FITC staining when stimulated with CpG. mRNA of DNA methyltransferase 1 (DNMT-1) and BCL-2 was increased when L-02 cells were stimulated with CpG DNA. Our study has identified a possible novel mechanism that indicates how CpG DNA of HBV DNA may contribute to the malignant transformation of benign liver cells.
Pubmed
Journal: Zhong nan da xue xue bao. Yi xue ban = Journal of Central South University. Medical sciences
September/7/2015
Abstract
OBJECTIVE
To study the prevalence and influencing factors of dyslipidemia in the elderly in Changsha.
METHODS
Multi-stage randomized cluster sampling method was used to select 3 500 persons aged 65 and over in Changsha. Levels of serum lipids were detected and questionnaire was used to investigate the related factors (such as smoking, drinking, history of chronic diseases).
RESULTS
The prevalence rate of dyslipidemia was 43.72%. The abnormal rate of serum triglyceride, cholesterol and low-density lipoprotein was 26.54%, 25.31% and 16.65%, respectively. Multiple logistic regression analysis showed that smoking, drinking, overweight or obesity were risk factors of dyslipidemia.
CONCLUSIONS
The incidence of dyslipidemia is high and the influencing factors are common among the elderly. Community health education will help improve the effect of prevention and control.
Pubmed
Journal: Current problems in cancer
August/14/2018
Abstract
OBJECTIVE
Considering that adjuvant radiation therapy is one of the most common treatment methods and the influence of the clinical target volume to treatment-related toxicity, this study aimed to observe the differences in treatment failures about involved-field irradiation (IFI) without lymph node areas versus elective nodal irradiation (ENI) with lymph node areas in elderly patients with bladder cancer.
METHODS
Ninety-two elderly bladder cancer patients were analyzed from January 2010 to December 2014 in one institution. The primary inclusion criteria were previous after transurethral resection of bladder tumor or partial cystectomy with adjuvant radiotherapy, and the radiation techniques included IFI or ENI. The study required that elderly patients did not received radiotherapy before treatment. We observed treatment-related toxicity and tumor failures, evaluated local progression-free survival, estimated the 3-year overall survival, and analyzed prognostic factors, after IFI and ENI in elderly bladder cancer patients. The outcomes were determined by chi square tests, Kaplan-Meier method and Cox multiple factors analysis.
RESULTS
In the experimental group, 42 patients (45.65%) received IFI, and a matched group of 50 patients (54.35%) received ENI. With a median follow-up of 31.47 months (range 4.00-86.00 months), the Kaplan-Meier analysis with a log-rank test demonstrated a statistical difference between the IFI group and the ENI group in acute toxicity (45.23% vs 72.00%, P = 0.008). However, there were no statistical differences in the 3-year overall survival rate (45.20% vs 48.00%, P = 0.860) or the duration of local progression-free survival (24.98 vs 34.30, P =0.729).
CONCLUSIONS
IFI is feasible in elderly bladder cancer patients, as shown by a decrease in acute toxicity and no increase in local failure. We need a large number of clinical trials and data to further confirm these results.
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Pubmed
Journal: Zhonghua shao shang za zhi = Zhonghua shaoshang zazhi = Chinese journal of burns
September/8/2003
Abstract
OBJECTIVE
To investigate the different location and the expression characteristics of epidermal stem cells in normal adult skin and scar tissue.
METHODS
Skin tissue specimens were harvested from the corresponding sites from 6 healthy volunteers and from scar tissue of 6 patients 1 year after major deep burn. beta1 integrin and keratin 19 (K19) were employed as the biochemical markers for stem cells and transit amplifying cells identification and keratin 14 (K14) and keratin 10 (K10) as markers for post-mitotic cells and terminally differentiated cells respectively. Integrin and keratin were determined by Elivision two-step immunohistochemistry.
RESULTS
The expression of beta1 integrin and the K19 positive cell count in the epithelial basal layers of scar tissue were evidently decreased and weakened than those in normal adult healthy skin. Furthermore, the positive cells expressing K14 in epidermis of scar tissue were only located in 2 - 3 layers of basal epidermis, and their number was much less than that in normal adult skin. Whereas the cells positively expressing K10 were distributed wider in area than that in normal healthy skin. The epidermal stem cells and transit amplifying cells in scar epidermis were much less in number than that in normal skin. The differentiation process of scar epidermal stem cells was different from that of normal skin. And the proportions of post-mitotic cells and terminally differentiated cells were abnormal.
CONCLUSIONS
The results indicated that the self-renewal ability of the scar epidermis was decreased, and the differentiation process of it was in disorder, which may be a reason for the abnormality of structure and function of the epidermis in scar, and a reason for the decreased ability of wound healing of scar tissue.
Pubmed
Journal: Small (Weinheim an der Bergstrasse, Germany)
December/17/2015
Abstract
Large-area and uniform three-dimensional (3D) β-Ni(OH)2 and NiO nanowalls were synthesized on a variety of rigid and flexible substrates via a simple aqueous chemical deposition process. The β-Ni(OH)2 nanowalls consist of single-crystal Ni(OH)2 nanosheets that were vertically grown on different substrates. The height, crystallinity, and morphology of the Ni(OH)2 nanowalls can be readily modified by adjusting the reaction time and concentration of the NiCl2 solution. The synthesis mechanism of the Ni(OH)2 nanowalls was determined through heterogeneous nucleation and subsequent oriented crystal growth. 3D NiO nanowalls were obtained by thermal decomposition of the Ni(OH)2 nanowalls at 400 °C in Ar atmosphere. Highly sensitive, selective gas sensors and electrochemical sensors based on these NiO nanowalls were developed. The chemiresistive gas sensors based on the NiO nanowalls grown on ceramic substrates exhibited an excellent performance with low detection limit for formaldehyde (8 ppb) and NO2 (15 ppb). The electrochemical sensor based on the NiO nanowalls grown on an FTO glass substrate had a superior selectivity to non-enzymatic glucose with a detection limit of 200 nm.
Pubmed
Journal: Plant physiology and biochemistry : PPB
July/28/2014
Abstract
A detailed understanding of the effect of natural products on plant growth and protection will underpin new product development for plant production. The isolation and characterization of a known secondary metabolite named harzianolide from Trichoderma harzianum strain SQR-T037 were described, and the bioactivity of the purified compound as well as the crude metabolite extract in plant growth promotion and systemic resistance induction was investigated in this study. The results showed that harzianolide significantly promoted tomato seedling growth by up to 2.5-fold (dry weight) at a concentration of 0.1 ppm compared with the control. The result of root scan suggested that Trichoderma secondary metabolites may influence the early stages of plant growth through better root development for the enhancement of root length and tips. Both of the purified harzianolide and crude metabolite extract increased the activity of some defense-related enzymes to response to oxidative stress. Examination of six defense-related gene expression by real-time reverse transcription-PCR analysis revealed that harzianolide induces the expression of genes involved in the salicylic acid (PR1 and GLU) and jasmonate/ethylene (JERF3) signaling pathways while crude metabolite extract inhibited some gene expression (CHI-II and PGIP) related to basal defense in tomato plants. Further experiment showed that a subsequent challenge of harzianolide-pretreated plants with the pathogen Sclerotinia sclerotiorum resulted in higher systemic resistance by the reduction of lesion size. These results indicate that secondary metabolites of Trichoderma spp., like harzianolide, may play a novel role in both plant growth regulation and plant defense responses.
Pubmed
Journal: The Journal of nutritional biochemistry
January/8/2017
Abstract
Vitamin A (VA) status and its metabolism affect hepatic metabolic homeostasis. We investigated if VA status and metabolism contribute to energy metabolism and expression of hepatic genes in the cycle of fasting and refeeding. Zucker lean rats with VA sufficient (VAS) or VA deficient (VAD) status were respectively grouped as: ad libitum (VAS-AD or VAD-AD), 48-h fasted (VAS-Fasted or VAD-Fasted), 48-h fasted and refed a VAS diet (VAS-Refed-VAS or VAD-Refed-VAS), or refed a VAD diet (VAS-Refed-VAD or VAD-Refed-VAD) for 6 h. Respiratory exchange ratio (RER) of rats fed the VAS or VAD diet was monitored for 6 weeks. From week four, rats fed the VAS diet had higher RER than those fed the VAD diet. VAS-Refed rats had higher plasma levels of glucose, triglyceride, insulin and leptin than VAD-Refed rats. The mRNA and protein levels of hepatic genes for fuel metabolism in the fasting and refeeding cycle were determined using real-time polymerase chain reaction and immunoblot, respectively. The mRNA levels of glucokinase (Gck), sterol regulatory element-binding protein 1c (Srebp-1c), and fatty acid synthase (Fas) were lowered in VAS-Fasted and VAD-Fasted rats, and increased in VAS-Refed-VAS, VAS-Refed-VAD and VAD-Refed-VAS, but not VAD-Refed-VAD, rats. The ACL and FAS protein levels only dropped in VAS-Fasted rats and increased in VAS-Refed-VAS rats. The GK protein level decreased only in VAS-Fasted rats, and increased in VAS-Refed-VAS, VAS-Refed-VAD and VAD-Refed-VAS (but not VAD-Refed-VAD) rats. We conclude that VA status and its metabolism in the fasting and refeeding cycle contribute to the regulation of hepatic gene expression in rats.
Pubmed
Journal: Scientific reports
July/1/2015
Abstract
The direct observation of single crystal graphene growth and its shape evolution is of fundamental importance to the understanding of graphene growth physicochemical mechanisms and the achievement of wafer-scale single crystalline graphene. Here we demonstrate the controlled formation of single crystal graphene with varying shapes, and directly observe the shape evolution of single crystal graphene by developing a localized-heating and rapid-quenching chemical vapor deposition (CVD) system based on electromagnetic induction heating. Importantly, rational control of circular, hexagonal, and dendritic single crystalline graphene domains can be readily obtained for the first time by changing the growth condition. Systematic studies suggest that the graphene nucleation only occurs during the initial stage, while the domain density is independent of the growth temperatures due to the surface-limiting effect. In addition, the direct observation of graphene domain shape evolution is employed for the identification of competing growth mechanisms including diffusion-limited, attachment-limited, and detachment-limited processes. Our study not only provides a novel method for morphology-controlled graphene synthesis, but also offers fundamental insights into the kinetics of single crystal graphene growth.
Pubmed
Journal: The Review of scientific instruments
June/9/2008
Abstract
We demonstrate the ability to excite and monitor many whispering gallery modes (WGMs) of a microsphere resonator simultaneously in order to make broadband optical absorbance measurements. The 340 microm diameter microsphere is placed in a microfluidic channel. A hemispherical prism is used for coupling the WGMs into and out of the microsphere. The flat surface of the prism seals the microfluidic channel. The slight nonsphericity in the microsphere results in coupling to precessed modes whose emission is spatially separated from the reflected excitation light. The evanescent fields of the light trapped in WGMs interact with the surrounding environment. The change in transmission observed in the precessed modes is used to determine the absorbance of the surrounding environment. In contrast to our broadband optical absorbance measurements, previous WGM sensors have used only a single narrow mode to measure properties such as refractive index. With the microfluidic cell, we have measured the absorbance of solutions of dyes (lissamine green B, sunset yellow, orange G, and methylene blue), aromatic molecules (benzylamine and benzoic acid), and biological molecules (tryptophan, phenylalanine, tyrosine, and o-phospho-L-tyrosine) at visible and ultraviolet wavelengths. The microsphere surface was reacted with organosilane molecules to attach octadecyl groups, amino groups, and fluorogroups to the surface. Both electrostatic and hydrophobic interactions were observed between the analytes and the microsphere surface, as indicated by changes in the measured effective pathlength with different organosilanes. For a given analyte and coated microsphere, the pathlength measurement was repeatable within a few percent. Methylene blue dye had a very strong interaction with the surface and pathlengths of several centimeters were measured. Choosing an appropriate surface coating to interact with a specific analyte should result in the highest sensitivity detection.
Pubmed
Journal: Optics letters
January/11/2012
Abstract
We theoretically study the effect of the applied magnetic field on the scattering properties of the nanowire surface plasmons coupled to two quantum dots. The dispersion relations of the surface plasmon are found to be upwardly displaced in the presence of an applied magnetic field. The symmetric double peaks in the transmission spectrum resulting from the interference between the localized and delocalized channels of the surface plasmon can combine together and the associated Fano lineshape will be smeared out when increasing the magnitude of the magnetic field.
Pubmed
Journal: Biosensors & bioelectronics
June/29/2017
Abstract
It is desirable but challenging to assemble various biomimetic properties into a functional catalytic cascade system. In this work, cupric oxide nanoparticles were investigated as oxidase mimics for the aerobic oxidation of cysteine to cystine with the generation of hydrogen peroxide. Coupling this property with the peroxidase-like activity of CuO nanoparticles, we constructed a self-organized cascade reaction system based on a single-component nanozyme, which includes the oxidation of cysteine to yield cystine and hydrogen peroxide and the hydrogen peroxide-mediated oxidation of terephthalic acid to produce a fluorescence change. Based on this artificial enzymatic cascade reaction system, a fluorometric assay method with a low detection limit of 6.6nM was established for cysteine determination. This platform was then applied for the detection of cysteine in pharmaceutical products and human plasma, which yielded satisfactory results. Our investigations open up a new route and holds promise for the development and applications of multifunctional nanomaterials as enzyme mimics.
Pubmed
Journal: ACS applied materials & interfaces
January/7/2016
Abstract
We describe the fabrication of ultrathin wrinkled N-doped carbon nanotubes by an in situ solid-state method. The positions of Co catalyst were first labeled by good-dispersion and highly loaded Au and Pt, indicating the most of Co are unsealed. The resultant unique nanoarchitecture, which exhibits the features of carbon nanotube and graphene with a combined effect of 1D and 2D carbon-based nanostructures, exhibited a superior ORR activity to carbon nanotubes and graphene. Moreover, the novel catalysts showed a better durability and higher tolerance to methanol crossover and poisoning effects than those of Pt/C.
Pubmed
Journal: Chemical communications (Cambridge, England)
October/31/2013
Abstract
Nano-solidified intermedias (NSI) of cisplatin were prepared via biomineralization and applied to reverse the drug resistance of cancers in vitro and in vivo by an alternative internalization pathway.
Pubmed
Journal: Nano letters
October/11/2016
Abstract
Surface defects in relation to surface compositions, morphology, and active sites play crucial roles in photocatalytic activity of graphitic carbon nitride (g-C3N4) material for highly reactive oxygen radicals production. Here, we report a high-efficiency carbon nitride supramolecular hybrid material prepared by patching the surface defects with inorganic clusters. Fe (III) {PO4[WO(O2)2]4} clusters have been noncovalently integrated on surface of g-C3N4, where the surface defects provide accommodation sites for these clusters and driving forces for self-assembly. During photocatalytic process, the activity of supramolecular hybrid is 1.53 times than pure g-C3N4 for the degradation of Rhodamine B (RhB) and 2.26 times for Methyl Orange (MO) under the simulated solar light. Under the mediation of H2O2 (50 mmol L-1), the activity increases to 6.52 times for RhB and 28.3 times for MO. The solid cluster active sites with high specific surface area (SSA) defect surface promoting the kinetics of hydroxide radicals production give rise to the extremely high photocatalytic activity. It exhibits recyclable capability and works in large-scale demonstration under the natural sunlight as well and interestingly the environmental temperature has little effects on the photocatalytic activity.
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