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1.
Mol Med ; 30(1): 11, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225568

RESUMO

Male infertility is a physiological phenomenon in which a man is unable to impregnate a fertile woman during a 12-month period of continuous, unprotected sexual intercourse. A growing body of clinical and epidemiological evidence indicates that the increasing incidence of male reproductive problems, especially infertility, shows a very similar trend to the incidence of diabetes within the same age range. In addition, a large number of previous in vivo and in vitro experiments have also suggested that the complex pathophysiological changes caused by diabetes may induce male infertility in multiple aspects, including hypothalamic-pituitary-gonadal axis dysfunction, spermatogenesis and maturation disorders, testicular interstitial cell damage erectile dysfunction. Based on the above related mechanisms, a large number of studies have focused on the potential therapeutic association between diabetes progression and infertility in patients with diabetes and infertility, providing important clues for the treatment of this population. In this paper, we summarized the research results of the effects of diabetes on male reproductive function in recent 5 years, elaborated the potential pathophysiological mechanisms of male infertility induced by diabetes, and reviewed and prospected the therapeutic measures.


Assuntos
Diabetes Mellitus , Infertilidade Masculina , Feminino , Humanos , Masculino , Infertilidade Masculina/etiologia , Infertilidade Masculina/terapia , Células Intersticiais do Testículo
2.
Cell Commun Signal ; 22(1): 507, 2024 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-39425166

RESUMO

Ovarian cancer is the second leading cause of gynecologic cancer death worldwide, with only 20% of cases detected early due to its elusive nature, limiting successful treatment. Most deaths occur from the disease progressing to advanced stages. Despite advances in chemo- and immunotherapy, the 5-year survival remains below 50% due to high recurrence and chemoresistance. Therefore, leveraging new research perspectives to understand molecular signatures and identify novel therapeutic targets is crucial for improving the clinical outcomes of ovarian cancer. Alternative splicing, a fundamental mechanism of post-transcriptional gene regulation, significantly contributes to heightened genomic complexity and protein diversity. Increased awareness has emerged about the multifaceted roles of alternative splicing in ovarian cancer, including cell proliferation, metastasis, apoptosis, immune evasion, and chemoresistance. We begin with an overview of altered splicing machinery, highlighting increased expression of spliceosome components and associated splicing factors like BUD31, SF3B4, and CTNNBL1, and their relationships to ovarian cancer. Next, we summarize the impact of specific variants of CD44, ECM1, and KAI1 on tumorigenesis and drug resistance through diverse mechanisms. Recent genomic and bioinformatics advances have enhanced our understanding. By incorporating data from The Cancer Genome Atlas RNA-seq, along with clinical information, a series of prognostic models have been developed, which provided deeper insights into how the splicing influences prognosis, overall survival, the immune microenvironment, and drug sensitivity and resistance in ovarian cancer patients. Notably, novel splicing events, such as PIGV|1299|AP and FLT3LG|50,941|AP, have been identified in multiple prognostic models and are associated with poorer and improved prognosis, respectively. These novel splicing variants warrant further functional characterization to unlock the underlying molecular mechanisms. Additionally, experimental evidence has underscored the potential therapeutic utility of targeting alternative splicing events, exemplified by the observation that knockdown of splicing factor BUD31 or antisense oligonucleotide-induced BCL2L12 exon skipping promotes apoptosis of ovarian cancer cells. In clinical settings, bevacizumab, a humanized monoclonal antibody that specifically targets the VEGF-A isoform, has demonstrated beneficial effects in the treatment of patients with advanced epithelial ovarian cancer. In conclusion, this review constitutes the first comprehensive and detailed exposition of the intricate interplay between alternative splicing and ovarian cancer, underscoring the significance of alternative splicing events as pivotal determinants in cancer biology and as promising avenues for future diagnostic and therapeutic intervention.


Assuntos
Processamento Alternativo , Neoplasias Ovarianas , Humanos , Feminino , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/patologia , Processamento Alternativo/genética , Animais
3.
Mol Pain ; 18: 17448069221097760, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35430901

RESUMO

Gout is a prevalent and painful inflammatory arthritis, and its global burden continues to rise. Intense pain induced by gout attacks is a major complication of gout. However, systematic studies of gout inflammation and pain are lacking. Using a monosodium urate (MSU) crystal-induced gout model, we performed genome-wide transcriptome analysis of the inflamed ankle joint, dorsal root ganglion (DRG), and spinal cord of gouty mice. Our results revealed important transcriptional changes, including highly elevated inflammation and broad activation of immune pathways in both the joint and the nervous system, in gouty mice. Integrated analysis showed that there was a remarkable overlap between our RNAseq and human genome-wide association study (GWAS) of gout; for example, the risk gene, stanniocalcin-1 (STC1) showed significant upregulation in all three tissues. Interestingly, when compared to the transcriptomes of human osteoarthritis (OA) and rheumatoid arthritis (RA) joint tissues, we identified significant upregulation of cAMP/cyclic nucleotide-mediated signaling shared between gouty mice and human OA with high knee pain, which may provide excellent drug targets to relieve gout pain. Furthermore, we investigated the common and distinct transcriptomic features of gouty, inflammatory pain, and neuropathic pain mouse models in their DRG and spinal cord tissues. Moreover, we discovered distinct sets of genes with significant differential alternative splicing or differential transcript usage in each tissue, which were largely not detected by conventional differential gene expression analysis approaches. Based on these results, our study provided a more accurate and comprehensive depiction of transcriptomic alterations related to gout inflammation and pain.


Assuntos
Gota , Ácido Úrico , Animais , Modelos Animais de Doenças , Estudo de Associação Genômica Ampla , Gota/induzido quimicamente , Gota/complicações , Gota/genética , Inflamação/complicações , Inflamação/genética , Camundongos , Dor/genética
4.
Sensors (Basel) ; 22(4)2022 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-35214250

RESUMO

With the increase in global energy demand, the exploration and development of natural gas hydrate in sea has become a research hotspot in recent years. However, the environmental problems that may be brought about by large-scale harvesting are still concerns. The terrain monitoring of the trial harvesting area can effectively prevent the geological disasters that may be caused by the development of hydrates. Therefore, we have developed a new terrain monitoring device, which can work in the deep sea for a long time. Firstly, the structure of the sensor arrays and bus-type control system of the device are introduced. Secondly, an arc model with an interpolation method is used for reconstruction of the monitored terrain. Thirdly, after the accuracy of the sensing arrays are verified in laboratory, the device was placed in the Shenhu area of the South China Sea for more than 6 months of in-situ monitoring. Finally, we analyzed the data and concluded that the terrain of the monitored area was relatively flat, where the maximum subsidence was 12.3 cm and the maximum uplift was 2.75 cm.


Assuntos
Geologia , China
5.
Entropy (Basel) ; 25(1)2022 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-36673180

RESUMO

Signed graph neural networks learn low-dimensional representations for nodes in signed networks with positive and negative links, which helps with many downstream tasks like link prediction. However, most existing signed graph neural networks ignore individual characteristics of nodes and thus limit the ability to learn the underlying structure of real signed graphs. To address this limitation, a deep graph neural network framework SiNP to learn Signed network embedding with Node Polarity is proposed. To be more explicit, a node-signed property metric mechanism is developed to encode the individual characteristics of the nodes. In addition, a graph convolution layer is added so that both positive and negative information from neighboring nodes can be combined. The final embedding of nodes is produced by concatenating the outcomes of these two portions. Finally, extensive experiments have been conducted on four significant real-world signed network datasets to demonstrate the efficiency and superiority of the proposed method in comparison to the state-of-the-art.

6.
Entropy (Basel) ; 25(1)2022 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-36673179

RESUMO

Graph neural network has been widely used in various fields in recent years. However, the appearance of an adversarial attack makes the reliability of the existing neural networks challenging in application. Premeditated attackers, can make very small perturbations to the data to fool the neural network to produce wrong results. These incorrect results can lead to disastrous consequences. So, how to defend against adversarial attacks has become an urgent research topic. Many researchers have tried to improve the model robustness directly or by using adversarial training to reduce the negative impact of an adversarial attack. However, the majority of the defense strategies currently in use are inextricably linked to the model-training process, which incurs significant running and memory space costs. We offer a lightweight and easy-to-implement approach that is based on graph transformation. Extensive experiments demonstrate that our approach has a similar defense effect (with accuracy rate returns of nearly 80%) as existing methods and only uses 10% of their run time when defending against adversarial attacks on GCN (graph convolutional neural networks).

7.
Small ; 17(13): e2006496, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33656798

RESUMO

Silicon-based semiconductor materials dominate modern technology for more than half a century with extraordinary electrical-optical performance and mutual processing compatibility. Now, 2D materials have rapidly established themselves as prospective candidates for the next-generation semiconductor industry because of their novel properties. Considering chemical and processing compatibility, silicon-based 2D materials possess significant advantages in integrating with silicon. Here, a systematic study is reported on the structural, electrical, and optical performance of silicon telluride (Si2 Te3 ) 2D material, a IV-VI silicon-based semiconductor with a layered structure. The ultrawide photoluminescence (PL) spectra in the range of 550-1050 nm reveals the intrinsic defects in Si2 Te3 . The Si2 Te3 -based field-effect transistors (FETs) and photodetectors show a typical p-type behavior and a remarkable broadband spectral response in the range of 405-1064 nm. Notably, the photoresponsivity and detectivity of the photodetector device with 13.5 nm in thickness and upon 405 nm illumination can reach up to 65 A W-1 and 2.81 × 1012 Jones, respectively, outperforming many traditional broadband photodetectors. It is believed this work will excite interests in further exploring the practical application of 2D silicon-based materials in the field of optoelectronics.

8.
Sensors (Basel) ; 19(5)2019 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-30841609

RESUMO

With the increase in the scale and complexity of underwater engineering, safety problems caused by underwater deformation have become increasingly prominent. Although the intensity fiber curvature sensor can be used for curvature monitoring on the ground, its sensing mechanism is still under investigation. This paper establishes the mathematical model of optical power relative loss and bending radius during deformation of the fiber sensitive region and uses the optical power meter to measure light intensity loss in the sensitive region, which verifies the correctness of the model and reveals the sensing mechanism of the intensity fiber curvature sensor, then optimizes the sensor signal conditioning circuit, applies the sensor to the single-point deformation curvature measurement, and analyzes its measurement error and accuracy. It is proved that the linear measurement range of the sensor is improved when compared with existing similar products.

9.
Sensors (Basel) ; 19(19)2019 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-31590421

RESUMO

The data synchronous acquisition is crucial to the seafloor subsidence monitoring system for gas hydrate mining areas based on microelectromechanical sensors (MEMS). Because the independent and high-precision time reference sources on land cannot be used on the seafloor, especially in the deep sea, a relative time synchronization method based on input/output (I/O) and controller area network (CAN) bus was proposed to realize the internal time synchronization of the system. To demonstrate the feasibility of the proposed method, tests including the deformation test of the MEMS sensor array under high pressure, synchronous accuracy test, and landslide and collapse simulation tests were carried out. The synchronization method was performed once every 24 h, and the time drift was reduced to 0.38 ms from more than 30 ms, demonstrating that method can achieve consistent internal time of the system. The method does not require additional hardware devices and has adjustable accuracy.

10.
Opt Express ; 26(3): 3087-3097, 2018 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-29401841

RESUMO

In this work, we propose an underwater wireless optical communication (UWOC) system using an arrayed transmitter/receiver and optical superimposition-based pulse amplitude modulation with 4 levels (PAM-4). At the transmitter side, we design a spatial summing scheme using a light emitting diode (LED) array, which is divided into two groups in a uniformly interleaved manner. With on-off keying (OOK) modulation for each group, optical superimposition-based PAM-4 can be realized. It has enhanced tolerance to the modulation nonlinearities of LEDs. We numerically investigate the feasibility of the proposed spatial summing scheme in various underwater channels via Monte Carlo simulation. With the increase of divergence angle of LEDs and link distance, the optical power distribution tends to be more uniform at the reception plane. It can significantly relax the requirement on the link alignment. Furthermore, we conduct a proof-of-concept experiment employing two blue LEDs. A multi-pixel photon counter (MPPC), containing an array of single-photon avalanche diodes (SPADs), is used as the detector. It has a much higher sensitivity and can further relax the requirement for pointing. Over a 2-m tap water channel, data rates of 6.144 Mb/s, 8.192 Mb/s, and 12.288 Mb/s were achieved by using the PAM-4 signal generated by optical superimposition, within a 2.5-MHz system bandwidth. With 0.570-mg/L Mg(OH)2, the measured optical power is just 12.890 µW after a 2-m underwater channel. The corresponding bit error rate (BER) of the 12.288-Mbs PAM-4 signal is 2.9 × 10-3, which is still below the forward error correction (FEC) limit of 3.8 × 10-3. It implies that the UWOC system based on the high-sensitivity MPPC with array structure has superior power efficiency and robustness.

11.
Int J Syst Evol Microbiol ; 66(8): 3029-3033, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27154162

RESUMO

A novel, Gram-stain-negative, motile, facultatively anaerobic bacterium, designated strain NF48T, was isolated from surface seawater around Zhoushan Islands. Cells were rod-shaped (1.1-3.9×0.5-0.9 µm). Strain NF48T was able to grow at 10-40 °C (optimum 30 °C), at pH 5.5-9.0 (optimum 6.5-8.0) and with 0.5-7.0 % (w/v) NaCl (optimum 2.0 %). The genomic DNA G+C content was 65.5 mol%. Chemotaxonomic analysis showed that the main isoprenoid quinone was Q-10 and the major fatty acids were C18 : 1ω7c and C16 : 0. The major polar lipids of strain NF48T were phosphatidylcholine, phosphatidylethanolamine and phosphatidylglycerol. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain NF48T belonged to the genus Seohaeicola with similarity values of 95.5-97.2 % to members of this genus, and was most closely related to Seohaeicola nanhaiensis SS011A0-7#2-2T (97.2 %). On the basis of the phenotypic, chemotaxonomic and phylogenetic characteristics, strain NF48T is suggested to represent a novel species of the genus Seohaeicola, for which the name Seohaeicola zhoushanensis sp. nov. is proposed. The type strain is NF48T (=MCCC 1K01157T=KCTC 42650T).


Assuntos
Filogenia , Rhodobacteraceae/classificação , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodobacteraceae/genética , Rhodobacteraceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
12.
Int J Syst Evol Microbiol ; 66(6): 2186-2191, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26956001

RESUMO

A novel Gram-stain-negative, rod-shaped (1.0-1.2×2.0-8.0 µm), non-motile without flagella strain, designated HSF7T, was isolated from deep seawater. Strain HSF7T was able to grow at 20-40 °C (optimum 35 °C), pH 5.5-9.0 (optimum pH 6.5) and 0-10 % (w/v) NaCl (optimum 2 %). The G+C content of the genomic DNA was 69 mol%. Bacteriochlorophyll a and poly-ß-hydroxybutyrate (PHB) granules were not found. The major fatty acids were C18 : 1ω7c (69.3 %), C16 : 0 (9.1 %) and C19 : 0 cyclo ω8c (6.6 %). The polar lipids were phosphatidylglycerol, three unknown aminophospholipids, an unknown phospholipid, an unknown aminolipid and two unknown lipids. The only isoprenoid quinone was Q-10. 16S rRNA gene sequence analysis revealed that strain HSF7T was most closely related toThalassobaculum salexigens DSM 19539T, Thalassobaculum litoreum DSM 18839T, Nisaeadenitrificans DSM 18348T and Oceanibaculum indicum MCCC 1A02083Twith pairwise sequence similarities of 95.56 %, 95.21 %, 93.64 % and 92.65 %, respectively. On the basis of genotypic, phenotypic, phylogenetic and chemotaxonomic characteristics, strain HSF7T represents a novel species of the genus Thalassobaculum, or which the name Thalassobaculum fulvum sp. nov. is proposed. The type strain is HSF7T(=KCTC 42651T=MCCC 1K01158T).


Assuntos
Filogenia , Rhodospirillaceae/classificação , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Rhodospirillaceae/genética , Rhodospirillaceae/isolamento & purificação , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/química
13.
ScientificWorldJournal ; 2014: 838019, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24983004

RESUMO

For the 4-DOF (degrees of freedom) trajectory tracking control problem of underwater remotely operated vehicles (ROVs) in the presence of model uncertainties and external disturbances, a novel output feedback fractional-order nonsingular terminal sliding mode control (FO-NTSMC) technique is introduced in light of the equivalent output injection sliding mode observer (SMO) and TSMC principle and fractional calculus technology. The equivalent output injection SMO is applied to reconstruct the full states in finite time. Meanwhile, the FO-NTSMC algorithm, based on a new proposed fractional-order switching manifold, is designed to stabilize the tracking error to equilibrium points in finite time. The corresponding stability analysis of the closed-loop system is presented using the fractional-order version of the Lyapunov stability theory. Comparative numerical simulation results are presented and analyzed to demonstrate the effectiveness of the proposed method. Finally, it is noteworthy that the proposed output feedback FO-NTSMC technique can be used to control a broad range of nonlinear second-order dynamical systems in finite time.


Assuntos
Modelos Teóricos , Algoritmos
14.
ACS Sens ; 9(10): 5234-5245, 2024 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-39320965

RESUMO

The development of all-solid-state precise pH electrodes holds significant importance in various fields, particularly in marine scientific research. To achieve this goal, we proposed a novel fabrication technique for an all-solid-state ruthenium oxide (Ti/RuOx) pH electrode. We thin-coated the RuCl3 precursor solution on a titanium wire substrate using a heat gun repeatedly and then calcined it in a mixture of Li2CO3 and Na2O2 at 400 °C to obtain a ruthenium oxide (RuOx) film. This RuOx film was subjected to acid treatment with dilute nitric acid, and a polytetrafluoroethylene heat shrink tube was wrapped around the non-RuOx film area. Finally, the RuOx film was fully immersed in a pH 4.00 buffer solution, finalizing the electrode preparation. The RuOx film exhibits a dense and regular conical morphology. The Ti/RuOx electrode demonstrates a good near-Nernstian response slope (e.g., -59.04 mV/pH at 25 °C), high linearity (e.g., R2 = 0.9999), rapid response (<1 s), low hysteresis (<3 mV), excellent reversibility, and good repeatability in the pH range of 2.00-10.00. After full hydration, the Ti/RuOx electrode shows a potential drift of 8.5 mV and a drift rate of approximately 0.27 mV/day over a period of 25 days, indicating good long-term stability. Furthermore, the Ti/RuOx electrode exhibits robust resistance against interference from various ions and low-concentration redox substances, ensuring a long storage life (at least 280 days), and high measurement accuracy (e.g., ± 0.02 pH units) for diverse water samples, including seawater, freshwater, and tap water. This study has evaluated the potential of the Ti/RuOx electrode as a reliable and accurate tool for pH measurements in marine scientific applications.


Assuntos
Eletrodos , Oxirredução , Titânio , Titânio/química , Concentração de Íons de Hidrogênio , Temperatura , Rutênio/química , Técnicas Eletroquímicas/métodos , Técnicas Eletroquímicas/instrumentação , Compostos de Rutênio/química
15.
Small Methods ; 8(2): e2300175, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37317014

RESUMO

GaN's outstanding physical characteristics allow for a wide range of applications in numerous industries. Although individual GaN-based ultraviolet (UV) photodetectors are the subject of in-depth research in recent decades, the demand for photodetectors array is rising as a result of advances in optoelectronic integration technology. However, as a prerequisite for constructing GaN-based photodetectors array, large-area, patterned synthesis of GaN thin films remains a certain challenge. This work presents a facile technique for pattern growing high-quality GaN thin films for the assembly of an array of high-performance UV photodetectors. This technique uses UV lithography, which is not only very compatible with common semiconductor manufacturing techniques, but also enables precise patterning modification. A typical detector has impressive photo-response performance under 365 nm irradiation, with an extremely low dark current of 40 pA, a high Ilight /Idark ratio over 105 , a high responsivity of 4.23 AW-1 , and a decent specific detectivity of 1.76 × 1012 Jones. Additional optoelectronic studies demonstrate the strong homogeneity and repeatability of the photodetectors array, enabling it to serve as a reliable UV image sensor with enough spatial resolution. These outcomes highlight the proposed patterning technique's enormous potential.

16.
J Hazard Mater ; 480: 135942, 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39326153

RESUMO

Several studies reported that the presence of microplastics (MPs)/nanoplastics (NPs) in marine environments can alter microbial community and function. Yet, the impact of aged MPs/NPs on deep sea sedimentary ecosystems under high hydrostatic pressure remains insufficiently explored. Herein, the sedimentary microbial community composition, co-occurrence network, assembly, and transfer of antibiotic resistance genes (ARGs) in response to aged MPs/NPs were investigated. Compared with the control, NPs addition significantly reduced bacterial alpha diversity (p < 0.05), whereas MPs showed no significant impact (p > 0.05). Moreover, networks under NPs exhibited decreased complexity than that under MPs and the control, including edges, average degree, and the number of keystone. The assembly of the microbial community was primarily governed by stochastic processes, and aged MPs/NPs increased the importance of stochastic processes. Moreover, exposure to MPs/NPs for one month decreased the abundance of antibiotic resistance genes (ARGs) (from 94.8 to 36.2 TPM), while exposure for four months increased the abundance (from 40.6 to 88.1 TPM), and the shift of ARGs in sediment was driven by both functional modules and microbial community. This study is crucial for understanding the stress imposed by aged MPs/NPs on sedimentary ecosystems under high hydrostatic pressure.

17.
Biosens Bioelectron ; 220: 114888, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36410156

RESUMO

In order to address the need for long-term, in-situ and inexpensive monitoring of dissolved oxygen (DO), a chitin-carrying microbial fuel cell (MFC) based DO sensor was developed using sediment anolyte, which had an extremely low cost of US$12.17 and comparable performance to certain commercial sensors. The MFC based DO sensor had a long lifetime of over half a year with chitin as the fuel, attributed to the syntrophic interactions between fermentative and exoelectrogenic microbes that were well developed for chitin degradation in anaerobic condition with sediment filling in the anode chamber. The use of sediment anolyte introduced hindered diffusion in the porous media, enabling the use of glass fiber as the separator to replace the ion exchange membrane and thus resulting in a much lower cost. Field tests of this MFC based DO sensor were conducted in fresh and saline waters respectively. Excellent performance was achieved with average deviations of <4.5% to three commercial methods of fiber optic sensor (HQ40d, HACH company, USA), Clark type sensor (Pro20i, YSI company, USA) and iodometry. This low-cost MFC sensor also showed a high reliability, with the same response of current generation to different DO levels in random 17-times tests, indicating its great market potentials for in-situ DO monitoring.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais , Oxigênio , Reprodutibilidade dos Testes , Quitina
18.
Nanomaterials (Basel) ; 13(14)2023 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-37513103

RESUMO

Nano-water-based drilling fluids (NWBDFs) are prepared using nano-copper oxide (CuO) and multiwalled carbon nanotubes (MWCNTs) as modification materials. The effects of the temperature and concentration of the nanoparticles (NPs) on the rheological properties are studied using a rotational rheometer and viscometer. Also, the influence of two NPs on the filtration properties is studied using a low-pressure and low-temperature filtration apparatus, as well as a scanning electron microscope (SEM). It is found that MWCNTs with a concentration of 0.05 w/v% have the most obvious influence on the NWBDFs, which improve the stability of the gel structure against temperature and also decrease the filtration rate. Finally, a theoretical model predicating the yield point (YP) and the plastic viscosity (PV) as a function of the temperature considering the influence of the NPs is developed based on DLVO theory.

19.
Environ Pollut ; 316(Pt 2): 120707, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36427829

RESUMO

Microplastics (MPs) can absorb halogenated organic compounds and transport them into marine anaerobic zones. Microbial reductive dehalogenation is a major process that naturally attenuates organohalide pollutants in anaerobic environments. Here, we aimed to determine the mechanisms through which MPs affect the microbe-mediated marine halogen cycle by incubating 2,4,6-trichlorophenol (TCP) dechlorinating cultures with various types of MPs. We found that TCP was dechlorinated to 4-chlorophenol in biotic control and polypropylene (PP) cultures, but essentially terminated at 2,4-dichlorophenol in polyethylene (PE) and polyethylene terephthalate (PET) cultures after incubation for 20 days. Oxygen-containing functional groups such as peroxide and aldehyde were enriched on PE and PET after incubation and corresponded to elevated levels of intracellular reactive oxygen species (ROS) in the microorganisms. Adding PE or PET to the cultures exerted limited effects on hydrogenase and ATPase activities, but delayed the expression of the gene encoding reductive dehalogenase (RDase). Considering the limited changes in the microbial composition of the enriched cultures, these findings suggested that microbial dechlorination is probably affected by MPs through the ROS-induced inhibition of RDase synthesis and/or activity. Overall, our findings showed that extensive MP pollution is unfavorable to environmental xenobiotic detoxification.


Assuntos
Clorofenóis , Microplásticos , Plásticos , Anaerobiose , Espécies Reativas de Oxigênio , Clorofenóis/toxicidade , Polietileno , Polietilenotereftalatos
20.
Sci Total Environ ; 881: 163366, 2023 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-37044349

RESUMO

To date, multiple studies have shown that the accumulation of microplastics (MPs)/nanoplastics (NPs) in the environment may lead to various problems. However, the effects of MPs/NPs on microbial communities and biogeochemical processes, particularly methane metabolism in cold seep sediments, have not been well elucidated. In this study, an indoor microcosm experiment for a period of 120 days exposure of MPs/NPs was conducted. The results showed that MPs/NPs addition did not significantly influence bacterial and archaeal richness in comparison with the control (p > 0.05), whereas higher levels of NPs (1 %, w/w) had a significant adverse effect on bacterial diversity (p < 0.05). Moreover, the bacterial community was more sensitive to the addition of MPs/NPs than the archaea, and Epsilonbacteraeota replaced Proteobacteria as the dominant phylum in the MPs/NPs treatments (except 0.2 % NPs). With respect to the co-occurrence relationships, network analysis showed that the presence of NPs, in comparison with MPs, reduced microbial network complexity. Finally, the presence of MPs/NPs decreased the abundance of mcrA, while promoting the abundance of pmoA. This study will help elucidate the responses of microbial communities to MPs/NPs and evaluate their effects on methane metabolism in cold seep ecosystems.


Assuntos
Microbiota , Plásticos , Plásticos/metabolismo , Polietileno/metabolismo , Bactérias/metabolismo , Archaea/metabolismo , Microplásticos/metabolismo , Metano/metabolismo
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