Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 2.114
Filtrar
1.
Small ; : e2202047, 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35570715

RESUMO

Ultralight and highly flexible aerogel sensors, composed of reduced graphene oxide cross-linked by sustainable-macromolecule-derived carbon, are prepared via facile freeze-drying and thermal annealing. The synergistic combination of cross-linked graphene nanosheets and micrometer-sized honeycomb pores gives rise to the exceptional properties of the aerogels, including superior compressibility and resilience, good mechanical strength and durability, satisfactory fire-resistance, and outstanding electromechanical sensing performances. The corresponding aerogel sensors, operated at an ultralow voltage of 0.2 V, can efficiently respond to a wide range of strains (0.1-80%) and pressures (13-2750 Pa) even at temperatures beyond 300 °C. Moreover, the ultrahigh-pressure sensitivity of 10 kPa-1 and excellent sensing stability and durability are accomplished. Strikingly, the aerogel sensors can also sense the vibration signals with ultrahigh frequencies of up to 4000 Hz for >1 000 000 cycles, significantly outperforming those of other sensors. These enable successful demonstration of the exceptional performance of the cross-linked graphene-based biomimetic aerogels for sensitive monitoring of mechanical signals, e.g., acting as wearable devices for monitoring human motions, and for nondestructive monitoring of cracks on engineering structures, showing the great potential of the aerogel sensors as next-generation electronics.

2.
ACS Omega ; 7(18): 15821-15840, 2022 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-35571828

RESUMO

The characteristics, distribution, and preservation of pores are vital in controlling the storage and distribution of shale gas. The Qiongzhusi Formation shales taken from different members with similar tectonic and thermal evolutions were used to evaluate the response of pore characteristics to minerals and sealing systems using field-emission scanning electron microscopy and gas adsorption. Because of differences in mineral structure and arrangement, feldspar, organic matter (OM)-clay, OM-rutile, and OM-apatite aggregates facilitate multiple types of pores in the shale and influence the relative proportions of surface porosity for different types of pores owing to differences in mineral structure and arrangement. Rigid frameworks and pressure shadows formed by rigid minerals and OM-mineral aggregates preserved OM and pores to some extent. The sealing capacity of the floor controls the sealing system and hydrocarbon expulsion efficiency of the Qiongzhusi Formation in different members. During thermal evolution, the amount of hydrocarbons generated and expelled affected the stress equilibrium state between the pore pressure and external stress, influencing the compaction intensity of shales. The OM pore development characteristics were evolved with variation in the stress equilibrium state in different sealing systems. Once the stress equilibrium state was disrupted, the OM pores deformed, narrowed, or even closed under the influence of compaction owing to the loss of overpressure support. The pore characteristics of the Qiongzhusi Formation shales responded significantly to different sealing systems. A few OM pores are flat and slitlike in the open system, whereas numerous OM pores are round and elliptical in the semiopen system. Meanwhile, the average diameter of the OM pores in the open system was reduced by approximately 40.2% compared with that of the semiopen system. Furthermore, the pore volume and specific surface area of the mesopores for open system shales were reduced by 38.4% and 37.7%, respectively, compared to the semiopen system. These findings will improve the understanding of the distribution and preservation of pore in shale and help assess the sweet-spot members for the Qiongzhusi Formation shale gas.

3.
Artigo em Inglês | MEDLINE | ID: mdl-35549055

RESUMO

Rational design of tumor-microenvironment (TME)-activated nanoformulation for precisely targeted cancer treatment has recently attracted an enormous attention. However, the all-in-one TME-activated theranostic nanosystems with a simple preparation and high biocompatibility are still rarely reported. Herein, catalase nanocrystals (CatCry) are first introduced as a tumor microenvironment activatable nanoplatform for selective theranostics of colon cancer. They are engaged as (i) a "nanoreactor" for silver nanoparticles (AgNP) synthesis, (ii) a nanovehicle for tumor delivery of anticancer drug doxorubicin (DOX), and (iii) an in situ O2 generator to relief tumor hypoxia. When CatCry-AgNP-DOX nanoformulation is within a tumor, the intratumoral H2S turns AgNP into Ag2S nanoparticles, inducing a photothermal effect and NIR-II emission under 808 nm laser irradiation and also triggering DOX release. Simultaneously, CatCry catalyzes intratumoral H2O2 into O2, relieving hypoxia and enhancing chemotherapy. In contrast, when delivered to healthy tissue without increased concentration of H2S, the developed nanoformulation remains in the "off" state and no theranostic action takes place. Studies with colon cancer cells in vitro and a murine colon cancer model in vivo demonstrated that CatCry-AgNP-DOX delivered a synergistic combination of PTT and enhanced chemotherapy, enabling complete eradication of tumor with minimal side effects. This work not only introduces nanoplatform for theranostics of H2S-rich tumors but also suggests a general strategy for protein-crystal-based nanomedicine.

4.
Bioengineered ; 13(5): 11782-11793, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35546047

RESUMO

The study is aimed to determine the effects of cynarin (Cyn) on mice with gouty arthritis (GA) induced by monosodium urate (MSU). We measured swelling in the hind paws of mice in vivo using Vernier calipers and ultrasound. The liver, kidney, and hind paws were stained with hematoxylin-eosin, and M1 type macrophages were detected in the hind paws using anti-F4/80 and anti-iNOS antibodies. The mRNA expression of inflammatory factors in bone marrow-derived macrophages (BMDMs) and in the hind paws was detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasomes and the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways were analyzed via western blotting. Cyn was detected in vitro using Cell Counting Kit-8 (CCK-8). Cyn treatment reduced hind paw swelling and M1 macrophage infiltration, suppressed the mRNA expression of inflammatory factors, and inhibited NLRP3 inflammasome activation in vivo, in addition to inhibiting the phosphorylation of IKKa/ß, p65, and c-Jun NH 2-terminal kinase (JNK). Furthermore, Cyn exerted anti-inflammatory and anti-swelling effects in mice with GA by regulating the NF-κB and JNK pathways and NLRP3 inflammasomes.

5.
Front Microbiol ; 13: 829027, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35547119

RESUMO

Environmental microorganisms (EMs) are ubiquitous around us and have an important impact on the survival and development of human society. However, the high standards and strict requirements for the preparation of environmental microorganism (EM) data have led to the insufficient of existing related datasets, not to mention the datasets with ground truth (GT) images. This problem seriously affects the progress of related experiments. Therefore, This study develops the Environmental Microorganism Dataset Sixth Version (EMDS-6), which contains 21 types of EMs. Each type of EM contains 40 original and 40 GT images, in total 1680 EM images. In this study, in order to test the effectiveness of EMDS-6. We choose the classic algorithms of image processing methods such as image denoising, image segmentation and object detection. The experimental result shows that EMDS-6 can be used to evaluate the performance of image denoising, image segmentation, image feature extraction, image classification, and object detection methods. EMDS-6 is available at the https://figshare.com/articles/dataset/EMDS6/17125025/1.

6.
Front Aging Neurosci ; 14: 827993, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35547622

RESUMO

Background: Spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominant hereditary ataxia, and, thus far, effective treatment remains low. Repetitive transcranial magnetic stimulation (rTMS) can improve the symptoms of spinal cerebellar ataxia, but the mechanism is unclear; in addition, whether any improvement in the symptoms is related to cerebellar metabolism has not yet been investigated. Therefore, the purpose of this study was to investigate the effects of low-frequency rTMS on local cerebellar metabolism in patients with SCA3 and the relationship between the improvement in the symptoms and cerebellar metabolism. Methods: A double-blind, prospective, randomized, sham-controlled trial was carried out among 18 SCA3 patients. The participants were randomly assigned to the real stimulation group (n = 9) or sham stimulation group (n = 9). Each participant in both the groups underwent 30 min of 1 Hz rTMS stimulation (a total of 900 pulses), differing only in terms of stimulator placement, for 15 consecutive days. To separately compare pre- and post-stimulation data (magnetic resonance spectroscopy (MRS) data and the International Cooperative Ataxia Rating Scale (ICARS) score) in the real and sham groups, paired-sample t-tests and Wilcoxon's signed-rank tests were used in the analyses. The differences in the ICARS and MRS data between the two groups were analyzed with independent t-tests and covariance. To explore the association between the changes in the concentration of cerebellar metabolism and ICARS, we applied Pearson's correlation analysis. Results: After 15 days of treatment, the ICARS scores significantly decreased in both the groups, while the decrease was more significant in the real stimulation group compared to the sham stimulation group (p < 0.001). The analysis of covariance further confirmed that the total ICARS scores decreased more dramatically in the real stimulation group after treatment compared to the sham stimulation group (F = 31.239, p < 0.001). The values of NAA/Cr and Cho/Cr in the cerebellar vermis, bilateral dentate nucleus, and bilateral cerebellar hemisphere increased significantly in the real stimulation group (p < 0.05), but no significant differences were found in the sham stimulation group (p > 0.05). The analysis of covariance also confirmed the greater change in the real stimulation group. This study also demonstrated that there was a negative correlation between NAA/Cr in the right cerebellar hemisphere and ICARS in the real stimulation group (r = - 0.831, p = 0.02). Conclusion: The treatment with rTMS over the cerebellum was found to induce changes in the cerebellar local metabolism and microenvironment in the SCA3 patients. The alterations may contribute to the improvement of the symptoms of ataxia in SCA3 patients.

7.
Infect Drug Resist ; 15: 2293-2299, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35517899

RESUMO

Purpose: To investigate the phenotypic and genomic characteristics of the multi-drug resistant and hypervirulent Klebsiella pneumoniae strain recovered from bacteremia. Methods: Antimicrobial susceptibility testing (AST) was performed by the microdilution method. Antimicrobial resistance genes, virulence-associated genes, multilocus sequence typing (MLST), and plasmid replicon were characterized by next-generation sequencing (NGS) and nanopore sequencing. S1 nuclease-pulsed field gel electrophoresis (S1-PFGE) and Southern blotting were performed to characterize the plasmid profile. Results: The hypervirulent colistin- and carbapenem-resistant K. pneumoniae strain DY2009 was identified as ST5571, co-carrying mcr-1, bla NDM-1, and bla OXA-10. In silico analysis found that it was K2 serotype. AST results revealed that DY2009 was resistant to carbapenems, cephalosporins, ciprofloxacin, chloramphenicol, and colistin but remained susceptible to aztreonam, gentamicin, amikacin, and tigecycline. Through the whole-genome analysis, a variety of virulence determinants were identified, including rmpA. Plasmid analysis confirmed that the mcr-1 and bla NDM-1 gene harbored a ~33 kb IncX4 plasmid and a ~44 kb IncX3 plasmid. In contrast, bla OXA-10 was encoded by chromosome. Conclusion: To the best of our knowledge, we first report the clinical hypervirulent K. pneumoniae isolate co-producing MCR-1, NDM-1, and OXA-10 causing bacteremia. We found that mcr-1 and bla NDM-1 genes were located on two self-conjugative epidemic plasmids, contributing to the widespread MCR-1 and NDM-1 in China. The results of this work improve our understanding of the genetic background of colistin- and carbapenem-resistant K. pneumoniae isolate from bacteremia and the resistance mechanisms. Our findings highlight the urgent need for infection control of such strain to prevent it from becoming an extensive-drug resistant clone.

8.
Inorg Chem ; 2022 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-35546557

RESUMO

Nanosized ERI-type aluminophosphate was prepared by the calcination of a precursor material (denoted as ECNU-38P) synthesized using 1,1,6,6-tetramethyl-1,6-diazacyclododecane-1,6-diium hydroxide (TDDH) as a structure-directing agent. The structure of ECNU-38P is related to ERI topology but exhibits a highly disordered manner and contains both four- and six-coordinated Al atoms. In situ XRD patterns revealed a rarely reported temperature-induced three-dimensional (3D)-to-3D structural transformation from ECNU-38P to the ordered ERI-type ECNU-38 zeolite at 573-623 K. Nanosized ERI-type silicoaluminophosphate Si-ECNU-38 was also obtained by introducing Si atoms into the synthetic system of ECNU-38P. The catalytic performance of ERI-type silicoaluminophosphates in the methanol-to-olefin (MTO) reaction was revealed to be highly related to the crystal sizes.

9.
Front Cardiovasc Med ; 9: 877140, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35548407

RESUMO

Background: Preliminary studies indicated that enhanced plasma levels of lipoprotein(a) [lp(a)] might link with the risk of calcific aortic valve disease (CAVD), but the clinical association between them remained inconclusive. This systematic review and meta-analysis were aimed to determine this association. Methods: We comprehensively searched PubMed, Embase, Web of Science, and Scopus databases for studies reporting the incidence of CAVD and their plasma lp(a) concentrations. Pooled risk ratio (RR) and 95% confidence interval (95% CI) were calculated to evaluate the effect of lp(a) on CAVD using the random-effects model. Subgroup analyses by study types, countries, and the level of adjustment were also conducted. Funnel plots, Egger's test and Begg's test were conducted to evaluate the publication bias. Results: Eight eligible studies with 52,931 participants were included in this systematic review and meta-analysis. Of these, four were cohort studies and four were case-control studies. Five studies were rated as high quality, three as moderate quality. The pooled results showed that plasma lp(a) levels ≥50 mg/dL were associated with a 1.76-fold increased risk of CAVD (RR, 1.76; 95% CI, 1.47-2.11), but lp(a) levels ≥30 mg/dL were not observed to be significantly related with CAVD (RR, 1.28; 95% CI, 0.98-1.68). We performed subgroup analyses by study type, the RRs of cohort studies revealed lp(a) levels ≥50 mg/dL and lp(a) levels ≥30 mg/dL have positive association with CAVD (RR, 1.70; 95% CI, 1.39-2.07; RR 1.38; 95% CI, 1.19-1.61). Conclusion: High plasma lp(a) levels (≥50 mg/dL) are significantly associated with increased risk of CAVD.

10.
Plants (Basel) ; 11(9)2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35567202

RESUMO

The 2021 summer heat waves experienced in the Pacific Northwest led to considerable fruit damage in many apple production zones. Sunburn browning (SB) was a particularly evident symptom. To understand the mechanism underlying the damage and to facilitate the early assessment of compromised fruit quality, we conducted a study on external characteristics and internal quality attributes of SB 'Ambrosia' apple (Malus domestica var. Ambrosia) and evaluated the fruit loss on five rootstocks. The cell integrity of the epidermal and hypodermal layers of fruit skins in the SB patch was compromised. Specifically, the number of chloroplasts and anthocyanin decreased in damaged cells, while autofluorescent stress-related compounds accumulated in dead cells. Consequently, the affected sun-exposed skin demonstrated a significant increase in differential absorbance between 670 nm and 720 nm, measured using a handheld apple DA meter, highlighting the potential of using this method as a non-destructive early indicator for sunburn damage. Sunburn browning eventually led to lower fruit weight, an increase in average dry matter content, soluble solids content, acidity, deteriorated weight retention, quicker loss of firmness, and accelerated ethylene emission during ripening. Significant inconsistency was found between the sun-exposed and shaded sides in SB apples regarding dry matter content, firmness, and tissue water potential, which implied preharvest water deficit in damaged tissues and the risk of quicker decline of postharvest quality. Geneva 935 (G.935), a large-dwarfing rootstock with more vigor and higher water transport capacity, led to a lower ratio of heat-damaged fruits and a higher yield of disorder-free fruits, suggesting rootstock selection as a long-term horticultural measure to mitigate summer heat stress.

11.
Nat Methods ; 2022 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-35577954

RESUMO

Spatial transcriptomics approaches have substantially advanced our capacity to detect the spatial distribution of RNA transcripts in tissues, yet it remains challenging to characterize whole-transcriptome-level data for single cells in space. Addressing this need, researchers have developed integration methods to combine spatial transcriptomic data with single-cell RNA-seq data to predict the spatial distribution of undetected transcripts and/or perform cell type deconvolution of spots in histological sections. However, to date, no independent studies have comparatively analyzed these integration methods to benchmark their performance. Here we present benchmarking of 16 integration methods using 45 paired datasets (comprising both spatial transcriptomics and scRNA-seq data) and 32 simulated datasets. We found that Tangram, gimVI, and SpaGE outperformed other integration methods for predicting the spatial distribution of RNA transcripts, whereas Cell2location, SpatialDWLS, and RCTD are the top-performing methods for the cell type deconvolution of spots. We provide a benchmark pipeline to help researchers select optimal integration methods to process their datasets.

12.
Front Oncol ; 12: 861807, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35574388

RESUMO

The role of methyltransferase-like 3 (METTL3), which participates in catalyzing N-methyladenosine (m6A) RNA modification, in gastric cancer (GC) is unclear. Here, we found that METTL3 was overexpressed in human GC. Functionally, we verified that METTL3 promoted tumor cell proliferation and angiogenesis through a series of phenotypic experiments. Subsequently, ADAMTS9 was identified as the downstream effector of METTL3 in GC, which could be degraded by the YTHDF2-dependent pathway. Finally, the data suggested that METTL3 might facilitate GC progression through the ADAMTS9-mediated PI3K/AKT pathway. Our study unveiled the fundamental mechanisms of METTL3 in GC progression. The clinical value of METTL3 in GC deserves further exploration.

13.
Sci Total Environ ; : 155610, 2022 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-35504380

RESUMO

Difenoconazole (DCZ) is a triazole fungicide that negatively affects aquatic organisms and humans. However, data regarding the reproductive toxicity of DCZ are insufficient. In this study, we used zebrafish (from 2 h post-fertilization [hpf] to adulthood) as a model to evaluate whether DCZ at environmentally relevant concentrations (0.1, 1.0, and 10.0 µg/L) induces reproductive toxicity. After exposure to DCZ, egg production and fertilization rates were reduced by 1.0 and 10.0 µg/L. A significant decrease in gamete frequency (late vitellogenic oocytes and spermatozoa) was observed at 10.0 µg/L. The concentrations of 17ß-estradiol (E2), testosterone (T), and vitellogenin (VTG) were disrupted in females and males by 1.0 and 10.0 µg/L. Exposure to 10.0 µg/L DCZ significantly inhibited the contact time between female and male fish, which was mainly achieved by affecting male fish. The transcription of genes involved in the hypothalamus-pituitary-gonad (HPG) axis was significantly changed after treatment with DCZ. Overall, these data show that the endocrine-disrupting effect of DCZ on the zebrafish HPG axis inhibited gamete maturation and disrupted reproductive behavior, reducing fertility.

14.
Sci Total Environ ; : 155626, 2022 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-35504393

RESUMO

Electric vehicles (EVs) have been promoted acceleratively to reduce greenhouse gas (GHG) emissions, however, the GHG emission reduction potential of different powertrain EVs has not been investigated thoroughly. In this study, we firstly quantified and compared the GHG emissions of different powertrain vehicles in a life cycle perspective with particular focus on energy and climate consequences, for current and future integrated scenarios, to facilitate carbon reduction assessment for Shanghai. Four major types of EVs were considered. The results show that life cycle total energy consumption and GHG emissions of all EVs are lower than that of gasoline internal combustion engine vehicles (GICEVs), among which battery-powered electric vehicles (BEVs) is the lowest. Compared with GICEVs, the total energy use and GHG emissions of BEVs decrease by 34.2% and 41.7% respectively. As the electrification of vehicle powertrain system innovates, the life cycle emissions of GHG are gradually concentrated to the upstream stage. The sensitivity analysis demonstrates that life cycle GHG emissions of vehicles are most sensitive to the proportion of thermal power than other three parameters (utilization rate of recycled steel, vehicle lifetime and curb weight). The scenario analysis indicates that BEVs present the more favorable carbon emission decline performance over other EVs from long term perspective. It is estimated that up to 12.5 million tons of GHG emissions could be reduced under the optimistic scenario in 2050 in Shanghai. In the process of energy conversion from oil to electricity in transport in Shanghai, BEVs should be constantly promoted.

15.
Phys Chem Chem Phys ; 2022 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-35506891

RESUMO

The emerging ferroelectric nematic liquid crystals have been attracting broader interests in new liquid crystal physics and their unique material properties. One big challenge for the ferroelectric nematic research is to enrich the material choice, which is now limited to RM734 and DIO families as representatives, in sharp contrast to the enormously diverse variety of the traditional apolar nematic liquid crystals. Here, we report a design of novel ferroelectric nematic materials with highly fluorinated and rigid mesogens. Noteworthily, they show distinct chemical structural features compared with previous aromatic ester-based molecules. The ferroelectric nematic phase was identified and confirmed through rigorous experiments. The bulk polarization was found to become purely along the long axis director, creating giant dielectric anisotropy. This work demonstrates a great potential for expanding ferroelectric nematic material diversity and will accelerate the corresponding application research and technology innovation.

16.
Front Comput Neurosci ; 16: 872978, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35493856

RESUMO

With the deployment of 5G Internet of Things (IoT) in the power system, the efficiency of smart grid is improved by increasing two-way interactions in different layers in smart grid. However, it introduces more attack interfaces that the traditional information security system in smart grid cannot response in time. The neuroscience-inspired models have shown their effectiveness in solving security and optimization problems in smart grid. How to improve the security mechanism in smart grid while taking into account the optimization of data transmission efficiency using neuroscience-inspired algorithms is the problem to be solved in this study. Therefore, an information security system based on artificial neural network (ANN) and improved multiple protection model is proposed. Based on the ANN algorithm, the link state sample space is used to train the model to obtain the optimal transmission path in 5G power communication network. Integrating the intelligent link state module, the zero-trust security protection platform using case-based learning algorithm is designed and taken as the first protection, the network security logical isolation facility is taken as the second protection, and the forward and backward isolation facilities are set as the third protection to achieve the strengthened security of 5G IoT in smart grid. The experimental results show the efficiency and effectiveness of the proposed algorithms. In addition, the experimental results also show that the proposed system can resist malicious terminal access, terminal hijacking, data tampering and eavesdropping, protocol fuzzy, and denial-of-service attacks, so as to reduce the security risks of 5G IoT in smart grid. Since the proposed system can be easily integrated into the existing smart grid structure in China, the proposed system can provide a reference for the design and implementation of 5G IoT in smart grid.

17.
Front Neurosci ; 16: 806876, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35495051

RESUMO

Autism spectrum disorder (ASD) is a basket term for neurodevelopmental disorders characterized by marked impairments in social interactions, repetitive and stereotypical behaviors, and restricted interests and activities. Subtypes include (A) disorders with known genetic abnormalities including fragile X syndrome, Rett syndrome, and tuberous sclerosis and (B) idiopathic ASD, conditions with unknown etiologies. Positron emission tomography (PET) is a molecular imaging technology that can be utilized in vivo for dynamic and quantitative research, and is a valuable tool for exploring pathophysiological mechanisms, evaluating therapeutic efficacy, and accelerating drug development in ASD. Recently, several imaging studies on ASD have been published and physiological changes during ASD progression was disclosed by PET. This paper reviews the specific radioligands for PET imaging of critical biomarkers in ASD, and summarizes and discusses the similar and different discoveries in outcomes of previous studies. It is of great importance to identify general physiological changes in cerebral glucose metabolism, cerebral blood flow perfusion, abnormalities in neurotransmitter systems, and inflammation in the central nervous system in ASD, which may provide excellent points for further ASD research.

18.
Quant Imaging Med Surg ; 12(5): 2917-2931, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35502397

RESUMO

Background: Due to different management strategy and prognosis of different subtypes of lung adenocarcinomas appearing as pure ground-glass nodules (pGGNs), it is important to differentiate invasive adenocarcinoma (IA) from adenocarcinoma in situ/minimally invasive adenocarcinoma (AIS/MIA) during lung cancer screening. The aim of this study was to develop and validate the qualitative and quantitative models to predict the invasiveness of lung adenocarcinoma appearing as pGGNs based on low-dose computed tomography (LDCT) and compare their diagnostic performance with that of intraoperative frozen section (FS). Methods: A total of 223 consecutive pathologically confirmed pGGNs from March 2018 to December 2020 were divided into a primary cohort (96 IAs and 64 AIS/MIAs) and validation cohort (39 IAs and 24 AIS/MIAs) according to scans (Brilliance iCT and Somatom Definition Flash) performed at Sichuan Cancer Hospital and Institute. The following LDCT features of pGGNs were analyzed: the qualitative features included nodule location, shape, margin, nodule-lung interface, lobulation, spiculation, pleural indentation, air bronchogram, vacuole, and vessel type, and the quantitative features included the diameter, volume, and mean attenuation. Multivariate logistic regression analysis was used to build a qualitative model, quantitative model, and combined qualitative and quantitative model. The diagnostic performance was assessed according to the following factors: the area under curve (AUC) of the receiver operating characteristic (ROC) curve, sensitivity, specificity, and accuracy. Results: The AUCs of the qualitative model, quantitative model, combined qualitative and quantitative model, and the FS diagnosis were 0.854, 0.803, 0.873, and 0.870, respectively, in the primary cohort and 0.884, 0.855, 0.875, and 0.946, respectively, in the validation cohort. No significant difference of the AUCs was found among the radiological models and the FS diagnosis in the primary or validation cohort (all corrected P>0.05). Among the radiological models, the combined qualitative and quantitative model consisting of vessel type and volume showed the highest accuracy in both the primary and validation cohorts (0.831 and 0.889, respectively). Conclusions: The diagnostic performances of the qualitative and quantitative models based on LDCT to differentiate IA from AIS/MIA in pGGNs are equivalent to that of intraoperative FS diagnosis. The vessel type and volume can be preoperative and non-invasive biomarkers to assess the invasive risk of pGGNs in lung cancer screening.

19.
Sci Adv ; 8(13): eabm5504, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35363521

RESUMO

Pleiotropic transcription regulator RNA polymerase II (Pol II)-associated factor 1 (PAF1) governs multiple transcriptional steps and the deposition of several epigenetic marks. However, it remains unclear how ultimate transcriptional outcome is determined by PAF1 and whether it relates to PAF1-controlled epigenetic marks. We use rapid degradation systems and reveal direct PAF1 functions in governing pausing partially by recruiting Integrator-PP2A (INTAC), in addition to ensuring elongation. Following acute PAF1 degradation, most destabilized polymerase undergoes effective release, which presumably relies on skewed balance between INTAC and P-TEFb, resulting in hyperphosphorylated substrates including SPT5. Impaired Pol II progression during elongation, along with altered pause release frequency, determines the final transcriptional outputs. Moreover, PAF1 degradation causes a cumulative decline in histone modifications. These epigenetic alterations in chromatin likely further influence the production of transcripts from PAF1 target genes.

20.
Materials (Basel) ; 15(7)2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35407677

RESUMO

Thin T2 copper sheets with nine different thicknesses were employed in uniaxial tensile tests to investigate the influence of service temperature and thickness on their tensile properties. A total of 33 groups of tensile samples were separately tested at 20 °C, 100 °C, 150 °C, 200 °C, and 250 °C to obtain their elongation and their tensile and yield strengths. The change laws of the tensile properties of the investigated T2 copper were analyzed using different fitting functions. The main results show that both sheet thickness and temperature have an important influence on the tensile properties of T2 copper. As the sheet thickness increased, the tensile and yield strengths of the tested materials first increased rapidly, then decreased sharply, and finally stabilized. As the temperature increased, the tensile strength increased linearly while the yield strength decreased linearly. The relationships between the elongation and the sheet thickness and temperature were exponential and polynomial functions, respectively. T-t-Rm, T-t-Rel, and T-t-δ empirical formulas were proposed and established to predict the tensile properties of the investigated T2 copper sheet, and the predictive models exhibited solid accuracy.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...