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1.
Front Biosci (Landmark Ed) ; 25: 513-525, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31585900

RESUMO

Merlin ((Moesin-ezrin-radixin-like protein, also known as schwannomin) is a tumor suppressor protein which is encoded by the neurofibromatosis type 2 gene, NF2. Loss of function mutations or deletions in NF2 which normally restrains tumor growth, leads to the formation of multiple tumors including schwannoma, meningioma and ependymoma. We tested whether NF2/Merlin is expressed and exerts similar control on proliferation of colorectal cancer cells and modulates the rate of their apoptosis. Expression of NF2/Merlin was reduced in colorectal cancer cells as compared with adjacent non-cancerous cells. Overexpression of NF2 inhibited colony formation by tumor cells and inhibited proliferation of cancer cells both in vitro and in vivo. The rate of apoptosis was also increased in colorectal cancer cells by overexpression of NF2. These findings show that NF2/Merlin is also reduced in tumors that do not arise in the context of neurofibromatosis and that induction of its expression might be used to control tumor growth.

2.
Front Biosci (Landmark Ed) ; 25: 536-548, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31585902

RESUMO

Hyperhomocysteinemia induces stress response in endoplasmic reticulum (ERS). Here, we tested whether blockage of homocysteine (Hcy) induced ERS and subsequent apoptosis in vascular smooth muscle cells can be inhibited by  blockage of PERK/eIF2α/ATF4/CHOP signaling. Short-term exposure of vascular smooth muscle cells to Hcy led to the phosphorylation of PERK (pPERK), which in turn, phosphorylated eIF2 alpha (peIF2a) and inhibited the unfolded protein response. Long-term Hcy exposure, however, increased the expression of ATF-4 and CHOP and led to apoptosis. Treatment of cells with salubrinal, a specific inhibitor for eIF2a decreased the expression of ATF-4 and CHOP, and prevented apoptosis. Together, the results show that PERK pathway is involved in Hcy-induced vascular smooth muscle cell apoptosis and that blocking the PERK pathway protects against this injury.

3.
Nanotechnology ; 31(2): 024001, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31550701

RESUMO

Nanostructured mesoporous carbon materials have been an attractive material for electrochemical energy storage in the recent decades. However, the controllable synthesis of two-dimensional mesoporous carbon with tunable thickness and desired pore structure is highly challenging. Here, a series of graphene@mesoporous nitrogen-doped carbon (denoted as G@mesoNC) core-shell structured nanosheets with tunable thicknesses have been fabricated via a sample hydrothermal method by using cellulose as the green and cheap carbon precursor. The resultant G@mesoNC nanosheets exhibit a distinct sandwich-like structure with tunable thicknesses (from 10 to 30 nm), a large surface area (562 m2 g-1), a narrow pore size distribution (2.3 nm) and a high nitrogen content (7.95%). Significantly, when being used as the electrode for supercapaciors, the resultant G@mesoNC nanosheets showcase a high specific capacitance of 264 F g-1. Most importantly, there is no substantial capacitance decay after 2500 cycles, indicating the perfect cyclic stability of G@mesoNC nanosheets. Our method paves a new way for synthesizing carbon electrodes for energy storage.

4.
Mater Sci Eng C Mater Biol Appl ; 106: 110265, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753343

RESUMO

Young's modulus is essential for the design and production of the alloys. Thus, we proposed a MGI (Materials Genome Initiative)-oriented strategy for the high-throughput development of Young's modulus databank in the single-phase alloys. In this study, 17 diffusion couples of the bcc Ti-rich Ti-Nb-Zr, Ti-Nb-Cr and Ti-Nb-Zr-Cr systems annealed at 1273 K for 25 h were experimentally prepared. Subsequently, the composition-dependent Young's moduli and hardness in the bcc Ti-rich Ti-Nb-Zr-Cr system were determined by combining the nanoindentation technique and the electron probe micro analysis (EPMA). Moreover, on the basis of the presently obtained experimental data, the Young's modulus databank in the bcc Ti-Nb-Zr-Cr system were established by means of the CALPHAD (CALculation of PHAse Diagrams) approach. Finally, the Ti-22.6 at.% Nb-30 at.% Zr-3.8 at.% Cr alloy was designed from the Young's modulus databank and verified by using the nanoindentation and cytotoxicity tests. The results reveal that the present MGI-oriented strategy with the combination of the high-throughput measurements and the CALPHAD approach is a very effective method to accelerate the design/development of novel bio-Ti alloys.

5.
J Phys Condens Matter ; 32(1): 013002, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31487703

RESUMO

Since the discovery of stripe order in La1.6-x Nd0.4Sr x CuO4 superconductors in 1995, charge ordering in cuprate superconductors has been intensively studied by various experimental techniques. Among these studies, scanning tunneling microscope (STM) plays an irreplaceable role in determining the real space structures of charge ordering. STM imaging of different families of cuprates over a wide range of doping levels reveal similar checkerboard-like patterns, indicating that such a charge ordered state is likely a ubiquitous and intrinsic characteristic of cuprate superconductors, which may shed light on understanding the mechanism of high-temperature superconductivity. In another class of high-temperature superconductors, iron-based superconductors, STM studies reveal several charge ordered states as well, but their real-space patterns and the interplay with superconductivity are markedly different among different materials. In this paper, we present a brief review on STM studies of charge ordering in these two classes of high-temperature superconductors. Possible origins of charge ordering and its interplay with superconductivity will be discussed.

6.
J Cell Physiol ; 235(2): 683-690, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31286522

RESUMO

tRNA-derived stress-induced RNAs (tiRNAs), important components of tRNA-derived fragments, are gaining popularity for their functions as small noncoding RNAs involved in cancer progression. Under cellular stress, tiRNAs are generated when mature tRNA is specifically cleaved by angiogenin and suggested to act as transducers or effectors involved in cellular stress responses. tiRNAs facilitate cells to respond to stresses mainly via reprogramming translation, inhibiting apoptosis, degrading mRNA, and generating stress granules. This review introduces the cellular biogenesis, molecular mechanisms, and biological roles of tiRNAs in stress response and disease regulation. A better understanding of their roles in regulating cancer may provide novel biomarkers or therapeutic targets for diagnosis and treatment.

7.
J Med Virol ; 92(1): 53-61, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31429946

RESUMO

Hepatitis B virus (HBV) DNA is vulnerable to editing by human apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like (APOBEC) cytidine deaminases. However, the distribution of APOBEC-induced mutations on HBV DNA is not well characterized. To this end, we obtained the HBV DNA sequence of HBV-infected individuals with and without hepatocellular carcinoma (HCC and non-HCC groups, respectively) from NCBI database and calculated the rapo values of APOBEC-induced TpCpW→TpKpW mutation prevalence in HBV DNA. The results showed that the APOBEC-induced mutations were mainly distributed in the minus strand of non-HCC-derived HBV DNA (rapo = 2.04), while the mutation on the plus-strand was weaker (rapo = 0.99). There were high APOBEC-induced mutation regions in the minus strand of HBV DNA 1 to 1000 nucleotides (nts) region and in the plus-strand of HBV DNA 1000 to 1500 nts region; the mutations in the 1 to 1000 nts region were mainly TpCpW→TpTpW mutation types (total T/G: 111/18) and a number of these were missense mutations (missense/synonymous: 35/94 in P gene, 17/15 in S gene, and 5/10 in X gene). The difference between minus to plus-strand rapo of HCC-derived HBV DNA (1.96) was greater than that of the non-HCC group (1.05). The minus-strand rapo of HCC-derived HBV DNA regions 1000 to1500nts and 1500 to 2000 nts (rapo = 4.2 and 4.2) was also higher than that of the same regions of non-HCC-derived HBV DNA (rapo = 1.2 and 1.1). Finally, the ratio of minus to plus-strand rapo was used to distinguish HCC-derived HBV DNA from non-HCC-derived HBV DNA. This study unraveled the distribution characteristics of APOBEC-induced mutations on double strands of HBV DNA from HCC and non-HCC samples. Our findings would help understand the mechanism of APOBECs on HBV DNA and may provide important insights for the screening of HCC.

8.
Mater Sci Eng C Mater Biol Appl ; 107: 110307, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761160

RESUMO

Biodegradable scaffolds play an important role in tissue engineering, and appropriate degradation and resorption rates of these scaffolds are necessary to accommodate tissue growth. Synthetic polymers are frequently used because of their ease of production, good biocompatibility and controllable degradation rates. However, monitoring the degradation of these polymers in vivo by a noninvasive approach remains limited. In this study, we designed a composite scaffold by labeling poly(lactic-co-glycolic acid) (PLGA) with gold nanoclusters (Au NCs), which were used for tracking in vivo degradation through dual-modal fluorescence/computed tomography (CT) imaging. The diameter of the Au NCs was approximately 2.5 nm, and the emission peak was at a wavelength of 700 nm. After labeling PLGA with the Au NCs, the fluorescence intensity of the Au NC/PLGA composite scaffold reached 9.0 × 109 (p/s/cm2/sr)/(µW/cm2), and the CT density of the scaffold increased to 200 HU. After the composite scaffold was implanted subcutaneously into nude mice, a continuous decrease in the fluorescence signal and CT value was observed. The mean fluorescence intensity was 8.3 × 109, 3.17 × 109, 2.26 × 109, 2.11 × 109, and 1.82 × 109 (p/s/cm2/sr)/(µW/cm2) from the first week to the fifth week, respectively. The mean CT value changed from 222.6 to 185.9, 149.1, 112.5, and 55.2 (Hounsfield unit, HU) at the different timepoints. Compared with the change in the fluorescence intensity, the change in the CT value was similar to the change in the weight, and the Pearson correlation coefficient between the change in the CT value and weight was 0.8626. Furthermore, the structure and morphology of the scaffolds at different timepoints were analyzed by three-dimensional (3-D) reconstruction. This novel method of noninvasive dynamic monitoring of biodegradable polymers in vivo provides insight into choosing suitable biomaterials for tissue engineering and regenerative medicine.

9.
J Nanosci Nanotechnol ; 20(3): 1685-1696, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31492331

RESUMO

The process in which the nanofiber membrane is used to remove heavy metal ions and separation of oil-water solution is analyzed. Herein, smooth structures are induced by rGO-g-PAO sheets, which could be attributed to the strong interaction between P(AN-MA) and rGO-g-PAO. It is rewarding to note that the P(AN-MA)/rGO-g-PAO nanofiber membrane would exhibit superhydrophilic traits in the air and ultra-low oil-adhesive traits underwater when the concentration of P(AN-MA) and PAO is 13 wt.% and 0.3 wt.%, respectively. The amidoxime (-C(NH2) NOH) groups on the membrane surface can efficiently adsorb copper (Cu(II)) (1.65 mmol/g) and chromium (Cr(VI)) (4.70 mmol/g) ions in the waste water. Meanwhile, the P(AN-MA)/rGO-g-PAO nanofiber membrane exhibits ultrahigh flux (~6150 LMH), satisfying rejection rate (~97%) and outstanding flux recovery ratio (~99%) in separating oil water emulsion.

10.
Spectrochim Acta A Mol Biomol Spectrosc ; 224: 117409, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31357050

RESUMO

A novel colorimetric and fluorescence turn-on chemosensor TBB with benzothiazolium moiety has been explored, which exhibited the high selectivity for cyanide ion (CN-) in THF-H2O (2:8, v/v) mixture. The aqueous solution of sensor TBB was scarcely emissive. In the presence of CN- ion, the nucleophilic addition of CN- with the benzothiazolium CN bond of TBB produced the new species TBB-CN, consequently resulting in the intense orange-red emission by aggregation-induced emission (AIE) effect. Meanwhile, the color of solution was changed from orange-yellow to light yellow. The sensing mechanism was verified by Mass spectrometry, NMR analysis and DFT calculations.

11.
J Nanosci Nanotechnol ; 20(5): 2722-2727, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-31635607

RESUMO

Optical properties and morphology of silica nanocapsules (ca. 40 nm of size) incorporated with multiple InP/ZnS quantum dots (QDs, ca. 3.5 nm of size) have been investigated systematically in a typical cell culture medium (Dulbecco Modified Eagle Medium, DMEM buffer) over a period of time. The stability of silica nanocapsules with multiple QDs are found to be more robust, compared to the original aqueous pristine QDs over a period of 6 h. However, their photoluminescence efficiency is decreased after 8 h, accompanied by a change in morphology of the silica capsules. This change in morphology is caused by the dissolution of silica by alkali, and alkali-earth cations in the buffer. Our results confirm that the silica nanocapsule surface modification occurs in aqueous solution, resulting in a change from hydroxyl to carboxyl group. We also discuss possible methods to further increase the stability of the silica nanocapsules in physiological solutions.

12.
Infection ; 2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673977

RESUMO

BACKGROUND: Severe fever and thrombocytopenia syndrome (SFTS) is an acute illness with a high mortality (16.2-29.1%). Unfortunately, there is no specific cure or vaccine for SFTS. METHODS: In this open-label study, two patients with SFTS were treated with favipiravir, a new antiviral drug. RESULTS: Patients had a sustainable virologic, immunologic and symptomatic recovery. CONCLUSIONS: Favipiravir may be a prosiming drug for the treatment of SFTS.

13.
Appl Opt ; 58(29): 7929-7934, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31674343

RESUMO

A fiber surface-enhanced Raman scattering (SERS) probe based on the depressed double cladding fiber (DDCF) is demonstrated. Due to the depressed cladding, the optical field distribution of the DDCF is more approachable to the outer surface than that of a no core fiber without depressed cladding, improving the excitation efficiency for generating Raman scattered light. The cladding diameter of the DDCF is only 80 µm, which is smaller than the core diameter (105 µm) of the input multimode fiber (MMF). This small cladding diameter ensures a well collection coupling from the DDCF to the MMF. The impact of the DDCF length on the performance of the probe is investigated. Raman spectra of Rhodamine 6G (R6G) are measured using the DDCF-based SERS probe, which is embedded in a microfluidic chip. The all-fiber optical path configuration realizes an all-fiber Raman detection system that is stable, portable, and convenient to operate. Such results confirm the applicability of the DDCF-based fiber probe in the all-fiber SERS detection area and indicate that the proposed SERS probe renders a new scheme for optimal design of the fiber SERS probe structure.

14.
Appl Opt ; 58(29): 8039-8045, 2019 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-31674357

RESUMO

We present a method to realize a single-notch microwave photonic filter (MPF) based on interferometry of a single, low-coherence broadband optical source (BOS). Normally, a notch MPF based on low-coherence interferometry requires independent control of two optical sources located in different wavebands. In this work, we use a single BOS to accurately perform destructive interference between a bandpass and an all-pass MPF. A frequency and bandwidth freely tunable single-notch MPF can thus be realized. The proposed method is theoretically analyzed and experimentally demonstrated. A notch depth of more than 30 dB and a continuously tunable frequency range from 2 to 18 GHz was demonstrated in the proof-of-concept experiment.

15.
Chem Biol Interact ; 315: 108871, 2019 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-31669218

RESUMO

Clopidogrel, a clinically used antiplatelet agent, can be readily hydrolyzed by human carboxylesterase 1A (CES1A) to release an inactive metabolite clopidogrel carboxylic acid (CCA). In this study, clopidogrel was used as a tool substrate to investigate the interspecies variation of clopidogrel hydrolysis in hepatic microsomes from various mammals including human and six laboratory animals (such as mouse, rat, rabbit, beagle dog, minipig and cynomolgus monkey). The results demonstrated that clopidogrel could be hydrolyzed into CCA by all tested hepatic microsomes from human or other mammals, but the hydrolytic rates greatly varied among species. Inhibition assays demonstrated that BNPP (an inactivator of mammalian CES) strongly inactivated clopidogrel hydrolytic activity in all tested hepatic microsomes, suggested that mammalian CES were major contributor(s) responsible for clopidogrel hydrolysis in hepatic preparations from all above-mentioned species. By contrast, the response of a reversible inhibitor of human CES1A on clopidogrel hydrolysis in these liver preparations varied significantly among different species. Moreover, the enzymatic kinetics and the apparent kinetic parameters of clopidogrel hydrolysis in hepatic microsomes from various animal species were evaluated and compared to each other. These findings provide crucial information for deeply understanding the differences in catalytic behaviors of mammalian CES, which will be very helpful for choosing suitable laboratory animal(s) for whole tests of CES1A substrate-drugs.

16.
Water Res ; 169: 115193, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31670083

RESUMO

The positive roles of N-acyl homoserine lactone (AHL)-mediated quorum sensing (QS) in aerobic granular sludge (AGS) have been widely acknowledged. However, it is not feasible to manipulate granulation via direct addition of AHL chemicals or AHL-producing strains. Here, several strains with high AHL-producing capacity were successfully isolated from AGS. These QS strains were cultivated, mixed as a consortium, and then divided into two groups: AHLs supernatant and bacterial cells encapsulated in sodium alginate (CEBs). The potential of QS regulation, via doses of AHLs supernatant and CEBs, in accelerating granulation was evaluated. Results clearly indicated that short-term (days 21-70) addition of AHLs supernatant led to a rapid specific growth rate (0.08 d-1), compact structure without filamentous bacteria overgrowth, excellent settlement performance (SVI10 37.2 mL/g), and a high integrity coefficient (4.4%) of the granules. Sustainable release of AHLs (mainly C6- and C8-HSL) was induced by exogenous AHLs, possibly attributed to the enrichment of the genera Aeromonas and Pseudomonas. Further, tryptophan and aromatic protein substances were produced to maintain structural stability, suggesting that short-term QS regulation had long-term positive effects on the characteristics of AGS. By comparison, the addition of CEBs posed negligible or negative impact on the granulation, as evidenced by the rupture of smaller aggregates and poor characteristics of AGS. Overall, augmentation of the signaling content via addition of AHLs supernatant from QS strains is an economical and feasible regulation strategy to accelerate granulation and sustain long-term structural stability.

17.
ACS Nano ; 13(11): 12767-12773, 2019 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-31697471

RESUMO

Polymersomes are a class of artificial liposomes, assembled from amphiphilic synthetic block copolymers, holding great promise toward applications in nanomedicine. The diversity in polymersome morphological shapes and, in particular, the precise control of these shapes, which is an important aspect in drug delivery studies, remains a great challenge. This is due to a lack of general methodologies that can be applied and the inability to capture the morphologies at the nanometer scale. Here, we present a methodology that can accurately control the shape of polymersomes via the addition of polyethylene glycol (PEG) under nonequilibrium conditions. Various shapes including spheres, ellipsoids, tubes, discs, stomatocytes, nests, stomatocyte-in-stomatocytes, disc-in-discs, and large compound vesicles (LCVs) can be uniformly captured by adjusting the water content and the PEG concentration. Moreover, these shapes undergo nonequilibrium changes in time, which is reflected in their phase diagram changes. This research provides a universal tool to fabricate all shapes of polymersomes by controlling three variables: water content, PEG concentration, and time. The use of the biofriendly polymer PEG enables the application of this methodology in the field of nanomedicine.

18.
Chem Res Toxicol ; 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31725283

RESUMO

Tofacitinib (TFT) is used for the treatment of moderately and severely active rheumatoid arthritis. Unfortunately, TFT was reported to induce leukopenia, and the underlying mechanisms remain unclear. The present study demonstrated that TFT was oxidized to a chemically reactive nitrenium ion by myeloperoxidase (MPO) occurring in neutrophils. The electrophilic ion showed chemical reactivity toward N-acetyl-cysteine (NAC) to produce two TFT-NAC conjugates (M1 and M2) in incubation of TFT with leucocytes in the presence of NAC. The generation of the nitrenium ion was verified by HClO-mediated oxidation of TFT. In addition, the nitrenium ion was found to react with sulfhydryl groups of cysteine residues of cellular protein in leucocytes after exposure to TFT. The study facilitates the understanding of the mechanisms of TFT toxic action.

19.
Adv Exp Med Biol ; 1101: 91-122, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31729673

RESUMO

Peripheral nervous system, widely spread in the whole body, is the important bridge for the transmission of neural signals. Signals from the central nervous system (brain and spinal cord) are transmitted to different parts of the body by the peripheral nerves, while along the way they also feedback all kinds of sensory information. Certain level of information integration and processing also occurs in the system. It has been shown that neural signals could be extracted from the distal end of the stump, indicating that the bridge is still effective after limb damage or amputation, which is the neurophysiological basis for the research and development of peripheral nerve interface for the prosthetic system.


Assuntos
Nervos Periféricos , Transdução de Sinais , Sistema Nervoso Central , Humanos , Regeneração Nervosa , Nervos Periféricos/fisiologia , Próteses e Implantes , Medula Espinal
20.
J Biomater Sci Polym Ed ; : 1-13, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31722618

RESUMO

Bacterial infections are a serious issue in wound healing. Extensive use of biocides in wound dressings have raised concerns of biocide resistance and unnecessary harm to normal skin cells. In this paper, we report a new approach to realize bacteria-triggered release of a biocide to the sites of bacterial infections from core-shell polyhydroxyalkanoate (PHA)-based nanofibers prepared by coaxial electrospinning. The hydrophobic PHA-based shell can prevent the biocide from undesirable payload release in physiological environments without pathogens. However, in the presence of pathogens, the PHA-based shell is degraded by the pathogens, and the encapsulated biocide is released. The released biocide subsequently can exert targeted antimicrobial effects on the bacteria. Using Pseudomonas aeruginosa as a model bacterium and dodecyltrimethylammonium chloride as a model biocide, we demonstrated that the core-shell PHA-based nanofibers effectively released encapsulated dodecyltrimethylammonium chloride in the presence of Pseudomonas aeruginosa, resulting in targeted inactivation of Pseudomonas aeruginosa cells.HighlightsUnique core-shell nanofibers were successfully fabricated from PHAs generated by bacteria.An on-demand release of biocide was achieved from a PHA-based core-shell nanofibours membrane.The membrane's mechanical properties closely match those of the human skin.

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