RESUMO
RNA has emerged as a revolutionary and important tool in the battle against emerging infectious diseases, with roles extending beyond its applications in vaccines, in which it is used in the response to the COVID-19 pandemic. Since their development in the 1990s, RNA interference (RNAi) therapeutics have demonstrated potential in reducing the expression of disease-associated genes. Nucleic acid-based therapeutics, including RNAi therapies, that degrade viral genomes and rapidly adapt to viral mutations, have emerged as alternative treatments. RNAi is a robust technique frequently employed to selectively suppress gene expression in a sequence-specific manner. The swift adaptability of nucleic acid-based therapeutics such as RNAi therapies endows them with a significant advantage over other antiviral medications. For example, small interfering RNAs (siRNAs) are produced on the basis of sequence complementarity to target and degrade viral RNA, a novel approach to combat viral infections. The precision of siRNAs in targeting and degrading viral RNA has led to the development of siRNA-based treatments for diverse diseases. However, despite the promising therapeutic benefits of siRNAs, several problems, including impaired long-term protein expression, siRNA instability, off-target effects, immunological responses, and drug resistance, have been considerable obstacles to the use of siRNA-based antiviral therapies. This review provides an encompassing summary of the siRNA-based therapeutic approaches against viruses while also addressing the obstacles that need to be overcome for their effective application. Furthermore, we present potential solutions to mitigate major challenges.
Assuntos
COVID-19 , Vírus , Humanos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/uso terapêutico , RNA Interferente Pequeno/metabolismo , Pandemias , COVID-19/genética , COVID-19/terapia , Interferência de RNA , Vírus/genética , Vírus/metabolismo , Antivirais/uso terapêutico , RNA ViralRESUMO
Virus filtration process is used to ensure viral safety in the biopharmaceutical downstream processes with high virus removal capacity (i.e., >4 log10 ). However, it is still constrained by protein fouling, which results in reduced filtration capacity and possible virus breakthrough. This study investigated the effects of protein fouling on filtrate flux and virus breakthrough using commercial membranes that had different symmetricity, nominal pore size, and pore size gradients. Flux decay tendency due to protein fouling was influenced by hydrodynamic drag force and protein concentration. As the results of prediction with the classical fouling model, standard blocking was suitable for most virus filters. Undesired virus breakthrough was observed in the membranes having relatively a large pore diameter of the retentive region. The study found that elevated levels of protein solution reduced virus removal performance. However, the impact of prefouled membranes was minimal. These findings shed light on the factors that influence protein fouling during the virus filtration process of biopharmaceutical production.
Assuntos
Filtração , Vírus , Hidrodinâmica , Membranas ArtificiaisRESUMO
OBJECTIVES: To apply radiomics analysis for overall survival prediction in chronic obstructive pulmonary disease (COPD), and evaluate the performance of the radiomics signature (RS). METHODS: This study included 344 patients from the Korean Obstructive Lung Disease (KOLD) cohort. External validation was performed on a cohort of 112 patients. In total, 525 chest CT-based radiomics features were semi-automatically extracted. The five most useful features for survival prediction were selected by least absolute shrinkage and selection operation (LASSO) Cox regression analysis and used to generate a RS. The ability of the RS for classifying COPD patients into high or low mortality risk groups was evaluated with the Kaplan-Meier survival analysis and Cox proportional hazards regression analysis. RESULTS: The five features remaining after the LASSO analysis were %LAA-950, AWT_Pi10_6th, AWT_Pi10_heterogeneity, %WA_heterogeneity, and VA18mm. The RS demonstrated a C-index of 0.774 in the discovery group and 0.805 in the validation group. Patients with a RS greater than 1.053 were classified into the high-risk group and demonstrated worse overall survival than those in the low-risk group in both the discovery (log-rank test, < 0.001; hazard ratio [HR], 5.265) and validation groups (log-rank test, < 0.001; HR, 5.223). For both groups, RS was significantly associated with overall survival after adjustments for patient age and body mass index. CONCLUSIONS: A radiomics approach for survival prediction and risk stratification in COPD patients is feasible, and the constructed radiomics model demonstrated acceptable performance. The RS derived from chest CT data of COPD patients was able to effectively identify those at increased risk of mortality. KEY POINTS: ⢠A total of 525 chest CT-based radiomics features were extracted and the five radiomics features of %LAA-950, AWT_Pi10_6th, AWT_Pi10_heterogeneity, %WA_heterogeneity, and VA18mm were selected to generate a radiomics model. ⢠A radiomics model for predicting survival of COPD patients demonstrated reliable performance with a C-index of 0.774 in the discovery group and 0.805 in the validation group. ⢠Radiomics approach was able to effectively identify COPD patients with an increased risk of mortality, and patients assigned to the high-risk group demonstrated worse overall survival in both the discovery and validation groups.
Assuntos
Doença Pulmonar Obstrutiva Crônica , Humanos , Estimativa de Kaplan-Meier , Modelos de Riscos Proporcionais , Doença Pulmonar Obstrutiva Crônica/diagnóstico por imagem , Tórax , Tomografia Computadorizada por Raios XRESUMO
Through time-dependent defect spectroscopy and low-frequency noise measurements, we investigate and characterize the differences of carrier trapping processes occurred by different interfaces (top/sidewall) of the gate-all-around silicon nanosheet field-effect transistor (GAA SiNS FET). In a GAA SiNS FET fabricated by the top-down process, the traps at the sidewall interface significantly affect the device performance as the width decreases. Compare to expectations, as the width of the device decreases, the subthreshold swing (SS) increases from 120 to 230 mV/dec, resulting in less gate controllability. In narrow-width devices, the effect of traps located at the sidewall interface is significantly dominant, and the 1/f 2 noise, also known as generation-recombination (G-R) noise, is clearly appeared with an increased time constant (τ i ). In addition, the probability density distributions for the normalized current fluctuations (ΔI D) show only one Gaussian in wide-width devices, whereas they are separated into four Gaussians with increased in narrow-width devices. Therefore, fitting is performed through the carrier number fluctuation-correlated with mobility fluctuations model that separately considered the effects of sidewall. In narrow-width GAA SiNS FETs, consequently, the extracted interface trap densities (N T ) distribution becomes more dominant, and the scattering parameter ([Formula: see text]) distribution increases by more than double.
RESUMO
Highly permselective and durable membrane materials have been sought for energy-efficient C3 H6 /C3 H8 separation. Mixed-matrix membranes (MMMs) comprising a polymer matrix and metal-organic frameworks (MOFs) are promising candidates for this application; however, rational matching of filler-matrix is challenging and their separation performances need to be further improved. Here, we propose a novel strategy of "defect engineering" in MOFs as an additional degree of freedom to design advanced MMMs. MMMs incorporated with defect-engineered MOFs exhibit exceptionally high C3 H6 permeability and maintained C3 H6 /C3 H8 selectivity, especially with enhanced stability under industrial mixed-gas conditions. The gas transport, sorption, and material characterizations reveal that the defect sites in MOFs provide the resulting MMMs with not only ultrafast diffusion pathways but also favorable C3 H6 sorption by forming complexation with unsaturated open metal sites, confirmed by in situ FT-IR studies. Most importantly, the concept is also valid for different polymer matrices and gas pairs, demonstrating its versatile potential in other fields.
RESUMO
OBJECTIVES: To investigate CT imaging features associated with poor clinical outcome after corticosteroid treatment in patients diagnosed with cryptogenic organizing pneumonia (COP) and connective tissue disease-related organizing pneumonia (CTD-OP) and to assess the difference in CT findings and treatment responses between COP and CTD-OP. METHODS: Chest CT images from 166 patients (COP, 131; CTD-OP, 35) with pathologically proven organizing pneumonia were reviewed by two thoracic radiologists. The type, distribution pattern, and extent of parenchymal abnormalities, along with other associated imaging features, were assessed for each patient. Logistic regression analyses were used to identify features associated with poor clinical outcomes such as residual disease (RD) and disease relapse. The differences between COP and CTD-OP were also analyzed. RESULTS: Consolidation involving more than 10% of parenchyma (hazard ratio [HR], 2.27), detectable bronchiectasis (HR, 3.59), and diagnosis of CTD-OP (HR, 4.31) were associated with a higher risk of RD after adjustments for patient age and sex. More than 10% consolidation involvement (HR, 2.54) and diagnosis of CTD-OP (HR, 6.42) were also associated with a higher risk of disease relapse. Compared with COP, CTD-OP demonstrated a greater extent of parenchymal abnormalities, especially consolidation, and was less likely to show a peribronchovascular distribution pattern. CONCLUSION: Bronchiectasis and a greater extent of consolidation were associated with RD, with the latter also being associated with disease relapse. Compared with COP, CTD-OP was associated with worse treatment outcomes and demonstrated a greater extent of parenchymal abnormalities, which were also less likely to show a peribronchovascular pattern. KEY POINTS: ⢠The presence of bronchiectasis and a high parenchymal involvement of consolidation on initial chest CT were associated with a worse response to corticosteroids in patients with organizing pneumonia. ⢠Connective tissue disease-related organizing pneumonia (CTD-OP) was associated with worse treatment outcomes than its idiopathic counterpart cryptogenic organizing pneumonia (COP). ⢠Compared with COP, CTD-OP generally demonstrated a greater extent of parenchymal abnormalities, especially consolidation, and was less likely to show a peribronchovascular distribution pattern.
Assuntos
Bronquiectasia/diagnóstico por imagem , Doenças do Tecido Conjuntivo/complicações , Pneumonia em Organização Criptogênica/diagnóstico por imagem , Doenças Pulmonares Intersticiais/diagnóstico por imagem , Corticosteroides/uso terapêutico , Idoso , Artrite Reumatoide/complicações , Pneumonia em Organização Criptogênica/tratamento farmacológico , Pneumonia em Organização Criptogênica/fisiopatologia , Dermatomiosite/complicações , Feminino , Humanos , Pulmão/diagnóstico por imagem , Pulmão/fisiopatologia , Doenças Pulmonares Intersticiais/tratamento farmacológico , Doenças Pulmonares Intersticiais/etiologia , Doenças Pulmonares Intersticiais/fisiopatologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Capacidade de Difusão Pulmonar , Recidiva , Escleroderma Sistêmico/complicações , Tomografia Computadorizada por Raios X , Capacidade Pulmonar Total , Resultado do Tratamento , Capacidade VitalRESUMO
Irradiation of MoS2 field-effect transistors (FETs) fabricated on Si/SiO2 substrates with electron beams (e-beams) below 30 keV creates electron-hole pairs (EHP) in the SiO2, which increase the interface trap density (Nit ) and change the current path in the channel, resulting in performance changes. In situ measurements of the electrical characteristics of the FET performed using a nano-probe system mounted inside a scanning electron microscope show that e-beam irradiation enables both multilayer and monolayer MoS2 channels act as conductors. The e-beams mostly penetrate the channel owing to their large kinetic energy, while the EHPs formed in the SiO2 layer can contribute to the conductance by flowing into the MoS2 channel or inducing the gate bias effect. The analysis of the device parameters in the initial state and the vent-evacuation state after e-beam irradiation can clarify the effect of the interplay between the e-beam-induced EHPs and ambient adsorbates on the carrier behavior, which depends on the thickness of the MoS2 layer. DC and low frequency noise analysis reveals that the e-beam-induced EHPs increase Nit from 109-1010 to 1011 cm-2 eV-1 in both monolayer and multilayer devices, while the interfacial Coulomb scattering parameter αSC increases by three times in the monolayer and decreases to one-tenth of its original value in the multilayer. In other words, an MoS2 layer with a thickness of â¼30 nm is less sensitive to adsorbates by surface screening. Thus, the carrier mobility in the monolayer device decreases from 45.7 to 40 cm2 V-1 s-1, while in the 30 nm-thick multilayer device, it increases from 4.9 to 5.6 cm2 V-1 s-1. This is further evidenced by simulations of the distribution of interface traps and channel carriers in the MoS2 FET before and after e-beam irradiation, demonstrating that Coulomb scattering decreases as the effective channel moves away from the interface.
RESUMO
The practical applicability of electronic devices is largely determined by the reliability of field effect transistors (FETs), necessitating constant searches for new and better-performing semiconductors. We investigated the stress-induced degradation of MoS2 multilayer FETs, revealing a steady decrease of drain current by 56% from the initial value after 30 min. The drain current recovers to the initial state when the transistor is completely turned off, indicating the roles of soft-traps in the apparent degradation. The noise current power spectrum follows the model of carrier number fluctuation-correlated mobility fluctuation (CNF-CMF) regardless of stress time. However, the reduction of the drain current was well fitted to the increase of the trap density based on the CNF-CMF model, attributing the presence of the soft-type traps of dielectric oxides to the degradation of the MoS2 FETs.
RESUMO
Recently, graphene-based membranes have been extensively studied, represented by two distinct research directions: (i) creating pores in graphene basal plane and (ii) engineering nanochannels in graphene layers. Most simulation results predict that porous graphene membranes can be much more selective and permeable than current existing membranes, also evidenced by some experimental results for gas separation and desalination. In addition, graphene oxide has been widely investigated in layered membranes with two-dimensional nanochannels, showing very intriguing separation properties. This review will cover state-of-the-art of graphene-based membranes, and also provide a material guideline on future research directions suitable for practical membrane applications.
RESUMO
OBJECTIVES: To compare a new integral-based half-band method (IBHB) and a conventional full-width half-maximum (FWHM) method in measuring peripheral airway dimensions at airway phantoms and thin-section computed tomography of chronic obstructive pulmonary disease (COPD). METHODS: The IBHB was validated and compared using airway phantoms and 50 patients with COPD. Airway parameters (wall area percentage [WA%], mean lumen radius, and mean wall thickness) were measured at fourth to sixth generations of the right apical bronchus. Matched results from 2 methods were compared and correlated with forced expiratory volume (FEV) in 1 second (FEV1), FEV1 / forced vital capacity (FVC), and global initiative for chronic obstructive lung disease (GOLD) stage. Linear regression analysis was performed using airway dimensions and emphysema index. RESULTS: The IBHB generated more accurate measurements at phantom study. Measured airway parameters by both methods at thin-section computed tomography study were significantly different (all P < 0.05, paired t test). The IBHB method-measured WA% and wall thickness were significantly smaller. Mean WA% with IBHB also showed better correlation than that with FWHM (FEV1, r = -0.52 vs -0.28; FEV1 / FVC, r = -0.41 vs r = -0.20; GOLD, 0.52 vs 0.33, respectively). Linear regression analysis revealed fifth-generation WA% measured by IBHB was an independent variable, and addition to emphysema index increased predictability (FEV1, r = 0.63; FEV1 / FVC, r = 0.61; GOLD, r = 0.70). CONCLUSIONS: The new IBHB measured peripheral airway dimensions differently than FWHM and showed better correlations with functional parameters in COPD.
Assuntos
Algoritmos , Broncografia/métodos , Pulmão/diagnóstico por imagem , Doença Pulmonar Obstrutiva Crônica/diagnóstico por imagem , Intensificação de Imagem Radiográfica/métodos , Interpretação de Imagem Radiográfica Assistida por Computador/métodos , Tomografia Computadorizada por Raios X/métodos , Idoso , Broncografia/instrumentação , Feminino , Humanos , Masculino , Imagens de Fantasmas , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tomografia Computadorizada por Raios X/instrumentaçãoRESUMO
The aim of this study was to provide accurate anatomical descriptions of the patterns of innervation of the brachialis muscle by the musculocutaneous, radial, and median nerves. Sihler's staining method was applied to 20 brachialis muscles from 10 cadavers to reveal the intramuscular distribution patterns of the musculocutaneous, radial, and median nerves. Three patterns of innervation of the brachialis muscle by the three studied nerves were found: single, double, and triple. These innervation patterns were categorized into four types: Type I--only the musculocutaneous nerve; Type II--double innervation by the musculocutaneous and radial nerves; Type III--double innervation by the musculocutaneous and median nerves; and Type IV--triple innervation by all three nerves. Single, double, and triple innervation patterns occurred 25%, 70% (Type II, 55%; Type III, 15%), and 5% of the samples, respectively. The brachialis muscle is not solely innervated by the musculocutaneous nerve but also by the radial and median nerves, thus making it a potentially triply innervated muscle. Double innervation of this muscle with either the musculocutaneous and median nerve or the musculocutaneous and radial nerves was also observed.
Assuntos
Braço/inervação , Nervo Mediano/anatomia & histologia , Músculo Esquelético/inervação , Nervo Musculocutâneo/anatomia & histologia , Nervo Radial/anatomia & histologia , Idoso , Idoso de 80 Anos ou mais , Cadáver , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
As water molecules permeate ultrafast through carbon nanotubes (CNTs), many studies have prepared CNTs-based membranes for water purification as well as desalination, particularly focusing on high flux membranes. Among them, vertically aligned CNTs membranes with ultrahigh water flux have been successfully demonstrated for fundamental studies, but they lack scalability for bulk production and sufficiently high salt rejection. CNTs embedded in polymeric desalination membranes, i.e., polyamide thin-film composite (TFC) membranes, can improve water flux without any loss of salt rejection. This improved flux is achieved by enhancing the dispersion properties of CNTs in diamine aqueous solution and also by using cap-opened CNTs. Hydrophilic CNTs were prepared by wrapping CNT walls via bio-inspired surface modification using dopamine solution. Cap-opening of pristine CNTs is performed by using a thermo-oxidative process. As a result, hydrophilic, cap-opened CNTs-embedded polyamide TFC membranes are successfully prepared, which show much higher water flux than pristine polyamide TFC membrane. On the other hand, less-disperse, less cap-opened CNTs-embedded TFC membranes do not show any flux improvement and rather lead to lower salt rejection properties.
RESUMO
BACKGROUND: Imaging findings of bilateral pulmonary vein atresia have not been described. OBJECTIVE: To describe cardiac CT findings and clinical outcomes of bilateral pulmonary vein atresia. MATERIALS AND METHODS: Three newborns with bilateral pulmonary vein atresia were encountered at our institution during a period of 8 years. We evaluated prenatal echocardiographic findings, clinical presentations, postnatal echocardiographic findings, chest radiographic findings, cardiac CT findings and clinical outcomes. RESULTS: All newborns presented immediately after birth with severe cyanosis, respiratory distress and acidosis that were unresponsive to medical management. Prenatal and postnatal echocardiographic studies and chest radiography were misleading, inconclusive or nonspecific in making the diagnosis in these children; however cardiac CT clearly demonstrated atresia of the bilateral pulmonary veins with multiple small mediastinal collateral veins and pulmonary edema. Surgical treatments were not feasible for this anomaly. Their clinical outcomes were universally dismal and all infants died within 3 days. CONCLUSION: Cardiac CT provides an accurate diagnosis of bilateral pulmonary vein atresia and leads to prompt treatment decision in these children.
Assuntos
Veias Pulmonares/anormalidades , Veias Pulmonares/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Malformações Vasculares/diagnóstico por imagem , Angiografia Coronária , Diagnóstico Diferencial , Evolução Fatal , Feminino , Humanos , Recém-Nascido , Masculino , Estudos RetrospectivosRESUMO
In research on membranes, the addition of co-solvents to the polymer dope solution is a common method for tuning the morphology and separation performance. For organic solvent nanofiltration (OSN) applications, we synthesized polybenzimidazole (PBI) membranes with high separation properties and stability by adding acetonitrile (MeCN) to the dope solution, followed by crosslinking with dibromo-p-xylene. Accordingly, changes in the membrane structure and separation properties were investigated when MeCN was added. PBI/MeCN membranes with a dense and thick active layer and narrow finger-like macrovoids exhibited superior rejection properties in the ethanol solution compared with the pristine PBI membrane. After crosslinking, they displayed superior rejection properties (96.56% rejection of 366-g/mol polypropylene glycol). In addition, the membranes demonstrated stable permeances for various organic solvents, including acetone, methanol, ethanol, toluene, and isopropyl alcohol. Furthermore, to evaluate the feasibility of the modified PBI OSN membranes, ecamsule, a chemical product in the fine chemical industry, was recovered. Correspondingly, the efficient recovery of ecamsule from a toluene/methanol solution using the OSN process with PBI/MeCN membranes demonstrated their applicability in many fine chemical industries.
RESUMO
Sterile filtration processes are widely used in the production of biotherapeutics for microorganism removal and product sterility. Sterile filtration processes can be applied to buffer preparation and cell culture media preparation in biotherapeutics processes, and to final sterilization or final filling in downstream processes. Owing to their broad range of applications in bioprocessing, various 0.2/0.22 µm sterile filters with different polymer materials (i.e., hydrophilic PVDF and PES) and nominal pore sizes are commercially available. The objective of this study was to evaluate two different commercial sterile filters in terms of filtration performance in various sterile filtration processes of biopharmaceutical production. The results demonstrate the importance of choosing the appropriate filter considering the process type and target removal/transport product to ensure efficient sterile filtration in the production of biotherapeutics.
RESUMO
Fabrication of highly efficient oil/water separation membranes is attractive and challenging work for the actual application of the membranes in the treatment of oily wastewater and cleaning up oil spills/oil leakage accidents. In this study, hydrophilic poly(ethylene-co-polyvinyl alcohol) (EVOH) nanofiber membranes were made using an electrospinning technique for oil/water separation. The as-prepared EVOH electrospun nanofiber membranes (ENMs) exhibited a super-hydrophilic property (water contact angle 33.74°) without further treatment. As prepared, ENMs can provide continuous separation of surfactant-free and surfactant-stabilized water-in-oil emulsions with high efficiency (i.e., flux 8200 L m−2 h−1 (LMH), separation efficiency: >99.9%). In addition, their high stability (i.e., reusable, mechanically robust) would broaden the conditions under which they can be employed in the real field oil/water separation applications. Various characterization techniques (including morphology investigation, pore size, porosity, mechanical properties, and performance test) for gravity-driven oil/water separation were employed to evaluate the newly prepared EVOH ENMs.
RESUMO
BACKGROUND: New ceramide (CER) NPs were prepared by linking fatty acids derived from oils of Korean traditional plants to phytosphingosine (PHS). The oils of Korean traditional plants were extracted from the seeds of Panax ginseng, Camellia sinensis, Glycine max napjakong, Glycine max seoritae, and Camellia japonica as sources of diverse fatty acids. AIMS: The aim of this study was to investigate signaling bioactivities of HP-C. sinensis ceramide NP that was column purified to remove any residual PHS and to evaluate the skin barrier functions of the HP-C. sinensis ceramide NP in human skin. METHODS: The expressions of genes related to epidermal differentiation were analyzed in vitro by qPCR. Human studies were also performed to determine the skin barrier functions with respect to TEWL and SC cohesion. RESULTS: The HP-C. sinensis CER NP significantly enhanced the expressions of FLG, CASP14, and INV indicates that the signaling biological activities of oil-derived ceramide NPs could be different depend on the natural oils. The control ceramide, C18-CER NP, had no effect on the expression of the three genes. HP-C. sinensis CER NP was selected for the in vivo human studies. Application of 0.5% HP-C. sinensis CER NP cream stimulated significantly faster recovery of a disrupted skin barrier than that of the control C18-CER NP. A significant enhancement of SC cohesion of the skin treated with 0.5% HP-C. sinensis CER NP was also observed. CONCLUSION: Taken all together, our results clearly demonstrate that HP-C. sinensis CER NP, P. ginseng CER NP, and other oil-derived CER NP could be a better choice for developing moisturizers to improve skin barrier function as they more closely mimic the endogenous CER composition of the actual human skin barrier.
Assuntos
Ceramidas , Pele , Humanos , Ceramidas/farmacologia , Ceramidas/análise , Ácidos Graxos , Homeostase , Óleos , República da Coreia , Pele/metabolismo , NanopartículasRESUMO
The membrane filtration process is the most widely used purification process in various industries due to its high separation efficiency, process simplicity, and low cost. Although there is a wide range of membrane products with diverse materials and pore sizes on the market, there is a technological gap between microfiltration and ultrafiltration membranes. Here we developed highly porous polyvinylidene fluoride (PVDF) membranes with a selective skin layer with a pore size range of 20 to 80 nm by using a thermal-vapor assisted phase separation method. Porous and bi-continuous sublayers were generated from spinodal decomposition induced by cooling. The overall membrane structure and pore size changed with the dope composition, while the pore size and thickness of the selective skin layer were effectively controlled by water vapor exposure. The excellent nanoparticle removal efficiencies of the prepared PVDF membranes were confirmed, indicating their potential application in high-level purification processes to remove small trace organic or inorganic impurities from various industrial fluids.
RESUMO
Carbon molecular sieve (CMS) membranes have been developed to replace or support energy-intensive cryogenic distillation for olefin/paraffin separation. Olefin and paraffin have similar molecular properties, but can be separated effectively by a CMS membrane with a rigid, slit-like pore structure. A variety of polymer precursors can give rise to different outcomes in terms of the structure and performance of CMS membranes. Herein, for olefin/paraffin separation, the CMS membranes derived from a number of polymer precursors (such as polyimides, phenolic resin, and polymers of intrinsic microporosity, PIM) are introduced, and olefin/paraffin separation properties of those membranes are summarized. The effects from incorporation of inorganic materials into polymer precursors and from a pyrolysis process on the properties of CMS membranes are also reviewed. Finally, the prospects and future directions of CMS membranes for olefin/paraffin separation and aging issues are discussed.
RESUMO
Heterogeneous clinical manifestations and progression of chronic obstructive pulmonary disease (COPD) affect patient health risk assessment, stratification, and management. Pulmonary function tests are used to diagnose and classify the severity of COPD, but they cannot fully represent the type or range of pathophysiologic abnormalities of the disease. To evaluate whether deep radiomics from chest computed tomography (CT) images can predict mortality in patients with COPD, we designed a convolutional neural network (CNN) model for extracting representative features from CT images and then performed random survival forest to predict survival in COPD patients. We trained CNN-based binary classifier based on six-minute walk distance results (> 440 m or not) and extracted high-throughput image features (i.e., deep radiomics) directly from the last fully connected layer of it. The various sizes of fully connected layers and combinations of deep features were experimented using a discovery cohort with 344 patients from the Korean Obstructive Lung Disease cohort and an external validation cohort with 102 patients from Penang General Hospital in Malaysia. In the integrative analysis of discovery and external validation cohorts, with combining 256 deep features from the coronal slice of the vertebral body and two sagittal slices of the left/right lung, deep radiomics for survival prediction achieved concordance indices of 0.8008 (95% CI, 0.7642-0.8373) and 0.7156 (95% CI, 0.7024-0.7288), respectively. Deep radiomics from CT images could be used to predict mortality in COPD patients.