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Introduction: Brain computer interfaces (BCI), which establish a direct interaction between the brain and the external device bypassing peripheral nerves, is one of the hot research areas. How to effectively convert brain intentions into instructions for controlling external devices in real-time remains a key issue that needs to be addressed in brain computer interfaces. The Riemannian geometry-based methods have achieved competitive results in decoding EEG signals. However, current Riemannian classifiers tend to overlook changes in data distribution, resulting in degenerated classification performance in cross-session and/or cross subject scenarios. Methods: This paper proposes a brain signal decoding method based on Riemannian transfer learning, fully considering the drift of the data distribution. Two Riemannian transfer learning methods based log-Euclidean metric are developed, such that historical data (source domain) can be used to aid the training of the Riemannian decoder for the current task, or data from other subjects can be used to boost the training of the decoder for the target subject. Results: The proposed methods were verified on BCI competition III, IIIa, and IV 2a datasets. Compared with the baseline that without transfer learning, the proposed algorithm demonstrates superior classification performance. In contrast to the Riemann transfer learning method based on the affine invariant Riemannian metric, the proposed method obtained comparable classification performance, but is much more computationally efficient. Discussion: With the help of proposed transfer learning method, the Riemannian classifier obtained competitive performance to existing methods in the literature. More importantly, the transfer learning process is unsupervised and time-efficient, possessing potential for online learning scenarios.
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Myocardial infarction (MI) is one of the leading causes of heart failure with highly complicated pathogeneses. miR-654-3p has been recognized as a pivotal regulator of controlling cell survival. However, the function of miR-654-3p in cardiomyocytes and MI has yet to be reported. This study aimed to identify the role of miR-654-3p in the regulation of myocardial infarction. To understand the contribution of miR-654-3p on heart function, we generated cardiac-specific knockdown and overexpression mice using AAV9 technology in MI injury. Mechanically, we combined cellular and molecular techniques, pharmaceutical treatment, RNA sequencing, and functional testing to elucidate the potential pathological mechanisms. We identified that mice subjected to MI decreased the expression of miR-654-3p in the border and infarcted area. Mice lacking miR-654-3p in the heart showed some inflammation infiltration and myocardial fibrosis, resulting in a mild cardiac injury. Furthermore, we found a deficiency of miR-654-3p in cardiomyocytes resulted in pyroptotic cell death but not other programmed cell death. Intriguingly, miR-654-3p deficiency aggravated MI-induced cardiac dysfunction, accompanied by higher myocardial fibrosis and cardiac enzymes and augmented pyroptosis activation. Cardiac elevating miR-654-3p prevented myocardial fibrosis and inflammation infiltration and decreased pyroptosis profile, thereby attenuating MI-induced cardiac damage. Using RNA sequence and molecular biological approaches, we found overexpression of miR-654-3p in the heart promoted the metabolic ability of the cardiomyocytes by promoting mitochondrial metabolism and mitochondrial respiration function. Our finding identified the character of miR-654-3p in protecting against MI damage by mediating pyroptosis and mitochondrial metabolism. These findings provide a new mechanism for miR-654-3p involvement in the pathogenesis of MI and reveal novel therapeutic targets. miR-654-3p expression was decreased after MI. Mice lacking miR-654-3p in the heart showed some inflammation infiltration and myocardial fibrosis, resulting in a mild cardiac injury. The deficiency of miR-654-3p in cardiomyocytes resulted in pyroptotic cell death. miR-654-3p deficiency aggravated MI-induced cardiac dysfunction, accompanied by higher myocardial fibrosis and cardiac enzymes and augmented pyroptosis activation. Overexpression of miR-654-3p prevented myocardial fibrosis and inflammation infiltration and decreased pyroptosis profile, thereby attenuating MI-induced cardiac damage. Overexpression of miR-654-3p in the heart promoted the metabolic ability of the cardiomyocytes by promoting mitochondrial metabolism and mitochondrial respiration function.
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MicroRNAs , Mitocôndrias , Infarto do Miocárdio , Miócitos Cardíacos , Piroptose , Animais , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Infarto do Miocárdio/genética , MicroRNAs/metabolismo , MicroRNAs/genética , Piroptose/genética , Camundongos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Mitocôndrias/metabolismo , Camundongos Endogâmicos C57BL , Masculino , Modelos Animais de Doenças , HumanosRESUMO
The booming demand on data security has aroused great interest for developing smart materials with temporal display feature and dynamic multicolor fluorescence. However, it remains challenging to implement both features on most responsive molecules. Herein, we construct a polymer free volume-controlled "molecular clock and emitter" via covalently embedding a multi-stimuli responsive molecular switch (i.e., spiropyran) into a polymer network (i.e., poly(pentafluorophenyl acrylate)) with programmable crosslink density and free volume. By the aminolysis of pentafluorophenyl ester with different amount of diamine crosslinkers, pPFPA-co-SP networks with controllable crosslink densities are generated, which have different confinement effects on the rate constant of SP/MC isomerization, thus leading to time-dependent photochromism. In addition, PTF1, a fluorescent probe that is sensitive to polymer rigidity, is introduced to further endow pPFPA-co-SP system with phototunable dynamic full-color emission. Therefore, relying on their synergistical responses to the rigidity of the polymer network, we have successfully developed a versatile molecular clock and emitter via an "one stone two birds" manner, which shows time-dependent data display along with dynamic multicolor fluorescence switching, providing great potential for advanced encryption and anticounterfeiting with a high security level.
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The current research on fracture conductivity ignores the placement of the proppant in fractures and relies on single-fracture conductivity testing and calculation, which cannot represent the overall conductivity of complex fracture systems. This research proposes a calculation method for the long-term conductivity of complex fractures based on proppant placement. This method considers fracture morphology, proppant placement, proppant embedment, and deformation under high closing pressure. The research results show that fracture conductivity decreases with increasing time, which can be divided into three stages: the embedding stage, the creep stage, and the stabilization stage. The long-term conductivity of the main fracture is higher than that of the branching fracture. With increasing closing pressure, the conductivities of both the main fracture and the branching fracture decrease. This is because increasing closure stress accelerates proppant embedment and creep, compressing the fluid flow space and further reducing fracture conductivity. Fracture conductivity is related to the placement of the proppant and sand concentration. Increasing the sand ratio can significantly increase the placement of the proppant in the main fracture and branching fractures, thereby improving fracture conductivity. Increasing the fracturing fluid viscosity can increase its proppant migration capacity. The proppant does not easily settle prematurely in high-viscosity fracturing fluid and can enter more into branching fractures, thereby improving their conductivity.
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Obsessive-compulsive disorder (OCD) is a chronic and debilitating psychiatric disorder that affects â¼2%-3% of the population globally. Studying spontaneous OCD-like behaviors in non-human primates may improve our understanding of the disorder. In large rhesus monkey colonies, we found 10 monkeys spontaneously exhibiting persistent sequential motor behaviors (SMBs) in individual-specific sequences that were repetitive, time-consuming and stable over prolonged periods. Genetic analysis revealed severely damaging mutations in genes associated with OCD risk in humans. Brain imaging showed that monkeys with SMBs had larger gray matter (GM) volumes in the left caudate nucleus and lower fractional anisotropy of the corpus callosum. The GM volume of the left caudate nucleus correlated positively with the daily duration of SMBs. Notably, exposure to a stressor (human presence) significantly increased SMBs. In addition, fluoxetine, a serotonergic medication commonly used for OCD, decreased SMBs in these monkeys. These findings provide a novel foundation for developing better understanding and treatment of OCD.
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Alstoscholarinoid A is a novel rearranged triterpene with an unprecedented 6/6/5/6/6/6 framework and an additional unique C28 â C11-olide F-ring, and displays antihyperuricemic bioactivity. Herein, we report a bio-inspired synthesis of alstoscholarinoid B in a stepwise manner, which is amenable to gram-scale synthesis. The synthesis involved the Chugaev elimination as a key step to realize the migration of the Δ11,12-double bond of oleanolic acid, and also featured a sequential LiHMDS-mediated intramolecular aldol condensation/lactonization to establish the polycyclic ring system. Additionally, a tandem deprotection/aldol condensation/lactonization process under the influence of LiI/2,4,6-collidine for forging the polycyclic scaffold was also serendipitously discovered. Mechanistic studies indicated that lithium carboxylate might function as an inner base for the chemoselective α-deprotonation of the C12-aldehyde.
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Background: Brain-derived neurotrophic factor (BDNF) is known to prevent methamphetamine (METH)-induced neurotoxicity and plays a role in various stages of METH addiction. However, there is a lack of research with longitudinal design on changes in plasma BDNF levels in active METH-dependent individuals. Aims: The aim of the study was to investigate changes in BDNF levels during METH self-administration in monkeys. Methods: This study measured plasma BDNF levels in three male rhesus monkeys with continuous METH exposure and four male control rhesus monkeys without METH exposure. Changes in plasma BDNF levels were then assessed longitudinally during 40 sessions of METH self-administration in the three monkeys. Results: Repeated METH exposure decreased plasma BDNF levels. Additionally, plasma BDNF decreased with long-term rather than short-term accumulation of METH during METH self-administration. Conclusions: These findings may indicate that the changes in peripheral BDNF may reflect the quantity of accumulative METH intake during a frequent drug use period.
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Herein, we achieved the asymmetric synthesis of (+)-vellosimine in 13 steps (longest linear sequences, LLS). This synthesis featured a sequential nucleophilic addition/cyclization process, which provided an efficient protocol for synthesizing a range of indole fused azabicyclo[3.3.1]nonane. Additionally, a SmI2-mediated reductive cyclization of ketone with an attached α,ß-unsaturated ester for constructing the strained quinuclidine moiety was also highlighted.
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Background/purpose: The incidence and patient population of medication-related osteonecrosis of the jaw (MRONJ) has dramatically increased due to the use of drugs suppressing bone metastasis. However, its clinical treatment is still very difficult. The aim of this study was to evaluate the effectiveness and outcome of immediate fibular flap reconstruction for MRONJ in the mandible. Materials and methods: Patients who underwent immediate fibular flap reconstruction for MRONJ in the mandible in our institution from 1990 to 2022 were screened and identified. Their demographics, drug history, symptoms, surgical parameters and follow-up data were collected and analyzed. Results: In total, 25 patients with MRONJ stage 3 were included. The main cause of drug administration was osseous metastasis (88%), and zoledronate was the main drug. Pain, swelling (44%), pyorrhea (28%), extraoral fistulas (16%) and necrotic bone exposure (12%) were the main chief complaints. After segmental mandibulectomy, the fibular flap harvest was 9.73 ± 3.37 cm, and 18/25 (72%) were cut into two segments to reconstruct the mandible. Sixty-eight percent had an intraoral skin paddle placed. All of the flaps survived, and 21/25 (84%) of the soft tissue underwent primary healing. During follow-up, the alleviation of symptoms was effective, and there was no primary disease progression or death. Conclusion: This is the largest comprehensive investigation of fibular flap reconstruction for MRONJ in the mandible, which is proved to be an alternative and effective treatment for managing advanced patients with MRONJ.
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Traditional security inks relying on fluorescent/phosphorescent molecules are facing increasing risks of forgery or tampering due to their simple readout scheme (i.e., UV-light irradiation) and the advancement of counterfeiting technologies. In this work, a multidimensional data-encryption method based on non-fluorescent polymers via a "lock-key" mechanism is developed. The non-fluorescent invisible polymer inks serve as the "lock" for data-encryption, while the anti-rigidochromic fluorophores that can distinctively light up the polymer inks with programed emissions are "keys" for decryption. The emission of decrypted data is prescribed by polymer chemical structure, molecular weight, topology, copolymer sequence, and phase structure, and shows distinct intensity, wavelength, and chirality compared with the intrinsic emission of fluorophores. Therefore, the data is triply encrypted and naturally gains a high-security level, e.g., only one out of 20 000 keys can access the only correct readout from 40 000 000 possible outputs in a three-polymers-based data-encryption matrix. Note that fluorophores lacking anti-rigidochrimism cannot selectively light up the inks and fail in data-decryption. Further, the diverse topologies, less well-defined structures, and random-coiled shapes of polymers make it impossible for them to be imitated. This work offers a new design for security inks and boosts data security levels beyond the reach of conventional fluorescent inks.
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Przhevalskiana silenus (warble fly) grubs cause myiasis in goats, in mountainous and semi-mountainous areas and different regions in Pakistan, and cause substantial losses to livestock. The palpation method for detecting warble flies generally neglects the infestation intensity; therefore, the development of a reliable and efficient diagnostic technique is extremely necessary. This study compared three indirect enzyme-linked immunosorbent assay (ELISA) methods for detecting anti-P. silenus antibodies using the hypodermin C (HyC) purified from Hypoderma spp. Larvae collected in cattle (local isolate, Microbiology Laboratory, PMAS-Arid Agriculture University, Rawalpindi), the crude antigen from the first instar stage of P. silenus, and a commercial Bovine Hypodermosis Antibody ELISA kit (IDEXX Laboratory), for accurately estimating the seroprevalence of goat warble fly infestation (GWFI) in the Pothwar plateau, Punjab, Pakistan. The ELISA with the crude antigen of P. silenus proved very sensitive and specific, 91% and 93%, respectively. The optical density exhibited a monthly variation, and the antibody titer began increasing from June, continually increased from July to December, and gradually decreased thereafter until March. The study confirmed the endemic status of GWFI in the Pothwar region and identified that ELISA based on the crude antigen of P. silenus was a more sensitive and specific immunodiagnostic method for determining seroprevalence, and could be employed for initiating nationwide eradication campaigns.
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Schistosomiasis is a zoonotic parasitic disease. Schistosoma japonicum eggs deposited in the liver tissue induce egg granuloma formation and liver fibrosis, seriously threatening human health. Natural killer (NK) cells kill activated hepatic stellate cells (HSCs) or induce HSC apoptosis and inhibit the progression of liver fibrosis. However, the function of NK cells in liver fibrosis caused by S. japonicum infection is significantly inhibited. The mechanism of this inhibition remains unclear. Twenty mice were percutaneously infected with S. japonicum cercariae. Before infection and 2, 4, 6, and 8 weeks after infection, five mice were euthanized and dissected at each time point. Hepatic NK cells were isolated and transcriptome sequenced. The sequencing results showed that Tigit expression was high at 4-6 weeks post infection. This phenomenon was verified by reverse transcription quantitative PCR (RT-qPCR) and flow cytometry. NK cells derived from Tigit-/- and wild-type (WT) mice were co-cultured with HSCs. It was found that Tigit-/- NK cells induced apoptosis in a higher proportion of HSCs than WT NK cells. Schistosomiasis infection models of Tigit-/- and WT mice were established. The proportion and killing activity of hepatic NK cells were significantly higher in Tigit-/- mice than in WT mice. The degree of liver fibrosis in Tigit-/- mice was significantly lower than that in WT mice. NK cells were isolated from Tigit-/- and WT mice and injected via the tail vein into WT mice infected with S. japonicum. The degree of liver fibrosis in mice that received NK cell infusion reduced significantly, but there was no significant difference between mice that received NK cells from Tigit-/- and WT mice, respectively. Our findings indicate that Tigit knockout enhanced the function of NK cells and reduced the degree of liver fibrosis in schistosomiasis, thus providing a novel strategy for treating hepatic fibrosis induced by schistosomiasis.
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Receptores Imunológicos , Schistosoma japonicum , Esquistossomose Japônica , Esquistossomose , Animais , Camundongos , Células Matadoras Naturais/metabolismo , Fígado/patologia , Cirrose Hepática/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Esquistossomose/patologiaRESUMO
Fasciolosis is a highly prevalent helminthic infection caused by Fasciola hepatica and F. gigantica. With the aim of identifying hybrid Fasciola flukes, multiplex PCR was performed to amplify the pepck gene. Furthermore, to determine Fasciola haplotypes, mitochondrial nad1 gene was amplified and sequenced, and phylogenetic analyses were performed. Adult Fasciola isolates were collected from 51 cattle and 51 sheep, genomic DNA was isolated, and one-step multiplex PCR was subsequently performed to amplify pepck. Isolates that generated a 510 bp band were identified as F. gigantica, those that generated a 241 bp band were identified as F. hepatica, and those that generated both bands were identified as hybrid (aspermic) flukes. Multiplex PCR data identified four isolates as F. gigantica and 84 as F. hepatica. Fourteen hybrid isolates (five cattle and nine sheep) were identified. On unidirectional DNA sequence analysis of nad1 PCR products, three sequences were identified as F. gigantica and 99 as F. hepatica. In addition, only 4 of 87 haplotypes detected for F. hepatica nad1 sequences were found to be previously reported, while the remaining 83 are unique to this study. To summarize, this study is the first to report the existence of hybrid Fasciola flukes and 83 unique haplotypes of F. hepatica in Turkey.
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A normal transverse laser differential confocal freeform measurement (NTDCFM) method was proposed to address the high-precision measurement difficulty of steep freeform surfaces with large variations in inclination, scattering, and reflectance. Using D-shaped diaphragm technology, the freeform surface under test (FSUT) axial variation transformed into a spot transverse movement on the detection focal plane. Meanwhile, a 2D position sensitive detector (PSD) was used to obtain the normal vector of the sampling points so that the measuring sensor's optical axis could track the FSUT normal direction. The focus tracking method extended the sensor measurement range. Theoretical analysis and experimental results showed that the axial resolution of the NTDCFM was better than 0.5â nm, the direction resolution of the normal vector was 0.1°, the maximum surface inclination could be measured up to 90°, the sensor range was 5 mm, and the measurement repeatability of the FSUT was better than 9â nm. It provides an effective new anti-inclination, anti-scattering, and anti-reflectivity method for accurately measuring steep freeform surfaces.
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In the context of climate change, this study uncovers the role of green airlines' social responsibility in conjunction with the consumers' switching behavior while considering the effects of latent variables, including green psychology, airline corporate image, green experimental behavior, green service fairness, green alternative attractiveness and switching intention, were examined in the study. In a highly competitive service environment, an organization needs to understand how passengers perceive its corporate image, satisfaction, fairness attractiveness, and behavior of switching intention. The predicted relationship was based on partial least squares structural equation modeling of a convenience sample of 615 valid datasets collected from individuals who used green airline services in China. The findings show that the psychological benefit of greenness, only warm glow, is the main driver of airline corporate image. Furthermore, airline corporate image, green service fairness, and green alternative attractiveness support passengers' green experiential satisfaction. The evidence demonstrates that green experiential satisfaction and green alternative attractiveness have significantly positive effects on switching intention. However, green service fairness has no significant effect on green switching intention. This study contributes to the literature by understanding airline customers' perception of the complex relationship in the green constructs. This finding can help marketers facilitate and develop their external communication and craft their image to retain their existing or potential customers.
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Herein, a striking anion-tunnel transfer effect was demonstrated in 1-butyl-3-methylimidazolium benzoate (BmimPhCOO) ionic liquid, so a rapid, mild and efficient benzoylation of cellulose is accomplished under catalyst-free condition in BmimPhCOO. In a wide temperature range of 20-80 °C, the equilibrium of reaction is reached within only 15 min, which is much faster than the reported acylation of cellulose. Furthermore, the resultant cellulose tribenzoates have excellent solubility in conventional organic solvents, thus they can be used to accurately reflect the molecular weight and dispersity index of cellulose raw materials by gel permeation chromatography. This method is suitable for various cellulose. Therefore, we found a new principle to realize the extremely-rapid acylation of cellulose, and proposed an effective approach to accurately determine the molecular weight parameters of cellulose.
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Molecular weight parameters are the key fundamental information of polymer materials, but the accurate characterization of the molecular weight of cellulose is extremely difficult due to its strong hydrogen bonding network. Herein, we demonstrated two new methods to accurately and rapidly measure the molecular weight parameters of cellulose by using 1-butyl-3-methylimidazolium acetate (BmimAc) ionic liquid (IL) as an additive. Cellulose is rapidly dissolved in BmimAc/DMSO (1:1, w/w) at room temperature at first. Then, DMAc is added to dilute the solution, and finally, the molecular weight and molecular weight distribution of cellulose samples are measured by the gel permeation chromatography (GPC) method with BmimAc/DMSO/DMAc (1:1:18, w/w) as the mobile phase. Such a simple method is suitable to all kinds of cellulose samples and exhibits an extremely high analytical efficiency which is 50 times higher than the previous GPC methods. In addition, a viscosity method that is available for industrial application was proposed by using the BmimAc/DMSO/DMAc (1:1:8, w/w) system with low viscosity. The relationship between the intrinsic viscosity of the cellulose/BmimAc/DMSO/DMAc solution and the molecular weight of cellulose is well established and is applicable to cellulose samples of Mw = 4.5 × 104 to 1.8 × 106, which is the widest applicable range among the reported viscosity methods. Overall, two new methods based on the use of BmimAc as an additive have many advantages, such as wide applicable range, simple preparation process, mild dissolution condition, no degradation or aggregation of cellulose, high accuracy, fast detection, and low IL consumption, overcoming the existing problems in the traditional methods. It is expected to be used as a standard procedure to characterize the molecular weight of cellulose in academia and industries.
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Líquidos Iônicos , Celulose/química , Líquidos Iônicos/química , Peso Molecular , ViscosidadeRESUMO
Neoadjuvant PD-(L)1 inhibitors may be promising for locally advanced non-small cell lung cancer (NSCLC) with potential pathological and survival benefits. But severe immune-related adverse events (irAEs) may cause fatal consequences which require early identification and timely intervention. The basis for most of these adverse events is a reactive hyperactivated T-cell response to normal tissues that results in the production of high levels of CD4 T-helper cell cytokines or increased migration of cytolytic CD8 T cells in normal tissues. It is recommended that all patients receiving PD-(L)1 inhibitors routinely have thyroid function studies, complete blood counts, and liver function and metabolic panels at each treatment and at intervals of 6 to 12 weeks for the first 6 months after finishing treatment. Herein, we report a rare case who had two grade 3-4 irAEs consecutively occurring after PD-1 induction therapy and surgery. A 59-year-old man with stage IIIA squamous cell lung cancer receiving 3 cycles of neoadjuvant nab-paclitaxel, carboplatin, and nivolumab was reevaluated for resectability. The patient experienced acute serum transaminase elevation right after induction therapy. Seven days after surgery he had severe pneumonia. These two serious complications were both eventually relieved by a month long treatment of corticosteroids but not regular medicine which verified the diagnosis of irAEs. Although results of clinical trials of neoadjuvant immunotherapy are worth expecting, our case calls attention to careful surveillance and timely management of irAEs during the perioperative use of PD-(L)1 inhibitors. We also further discuss the standard use of corticosteroids for irAEs based on a review of literature.
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BACKGROUND: The target of our study was to investigate if the size (greater than and less than 1 cm) of ground-glass opacities (GGOs) of adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) of the lung influences the rate of their evolution. METHODS: We retrospectively analyzed patients with AIS and MIA who underwent surgery at Shanghai Chest Hospital, Shanghai Jiao Tong University between January 2018 and July 2019, focusing on histopathology, surgical procedure, epidermal growth factor receptor (EGFR) mutations, and computed tomography (CT) images. RESULTS: A total of 224 AIS (n=117) and MIA (n=107) tumors were analyzed. The patients with a tumor diameter <1 cm were distinctly younger than those with tumors >1 cm in size (P<0.001). Pure ground-glass opacities (pGGO) occurred significantly more in patients with nodules <1 cm, while part-solid/mixed ground-glass opacities (mGGO) predominated in patients with nodules >1 cm (P=0.047). There was no significant difference in GGO evolution for GGOs of different sizes. Mutations of EGFR were more common in patients with MIA than in those with AIS (P<0.001). CONCLUSIONS: We found that GGO size and variation (pGGO or mGGO) did not correlate to tumor stability, therefore larger GGOs can undergo standard follow-up protocols to evaluate their evolution over time.
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BACKGROUND: Recent studies indicate that ultrasound can detect changes in tracheal diameter during endotracheal tube (ETT) cuff inflation. We sought to assess the accuracy of ultrasound measurement of tracheal diameter, and to determine the relationship between tracheal wall pressure (TWP), cuff inflation volume (CIV), and the degree of tracheal deformation. METHODS: Our study comprised two parts: the first included 45 porcine tracheas, the second 41 porcine tracheas. Each trachea was intubated with a cuffed ETT, which was connected to an injector and the manometer via a three-way tap. The cuff was inflated and the cuff pressure recorded before and after intubation. The tracheal diameter was measured using ultrasound. This included three separate measurements: outer transverse diameter (OTD), internal transverse diameter (ITD), and anterior tracheal wall thicknesses (ATWT). A precision electronic Vernier caliper was also used to measure tracheal diameter. We calculated TWP and the percentage change of tracheal diameter. The Bland-Altman method, linear regression, and locally weighted regression (LOESS) were used to analyze the data. RESULTS: There were strong correlation and agreement for OTD (r = 0.97, P < 0.001) and ITD (r = 0.90, P < 0.001) as measured by ultrasound and by precision electronic Vernier caliper, but a poor correlation for ATWT (r = 0.58, P < 0.001). There was a strong correlation between the percentage change of OTD (OTD%, r = 0.75, P < 0.001) and CIV, the percentage change of ITD (ITD%, r = 0.77, P < 0.001) and CIV, TWP (r = 0.75, P < 0.001) and CIV. And a strong correlation was also found between TWP and OTD% (r = 0.84, P < 0.001), TWP and ITD% (r = 0.84, P < 0.001). CONCLUSIONS: Use of ultrasound to measure OTD and ITD is accurate, but is less accurate for ATWT. There is a close correlation between OTD%, ITD%, CIV and TWP.