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1.
Zhonghua Yi Xue Za Zhi ; 103(41): 3294-3300, 2023 Nov 07.
Artículo en Chino | MEDLINE | ID: mdl-37926574

RESUMEN

Objective: To analyze the PET/CT imaging features of fluoride 18F-fluorodeoxyglucose (18F-FDG) in patients with various types of Parkinson's syndrome (PS), and to establish a "diagnostic tree" model of 18F-FDG PET/CT for PS. Methods: Data of patients with Parkinson's disease (PD), patients with multiple system atrophy cerebellar type (MSA-C), and patients with multiple system atrophy Parkinson's type (MSA-P)admitted to the Neurology Department of Huashan Hospital affiliated to Fudan University from January 2019 to December 2021. 18F-FDG PET/CT examination was conducted in all patients. Clinical and follow-up data was collected to determine clinical diagnosis. The specific patterns of brain glucose metabolism in patients with various types of Parkinsonism were observed and their utility in the differential diagnosis of the disease was analyzed. 18F-FDG PET/CT imaging"diagnostic tree"model was established and its value in the differential diagnosis of Parkinsonism was verified. Results: A total of 320 patients, 187 males and 133 females, aged (62±9) years, were enrolled in our study, including 80 PD, 90 PSP, 114 MSA-C and 36 MSA-P patients. The differential diagnostic features of cerebral glucose metabolism of Parkinsonism were as follows: the metabolism of putamen increased in PD patients, the metabolism of caudate nucleus, thalamus, midbrain, and frontal lobe decreased in PSP patients, the metabolism of cerebellum decreased in MSA-C patients, and the metabolism of putamen and cerebellum decreased in MSA-P patients. The sensitivity and specificity of the"diagnostic tree"model are 88.75% and 91.25% for PD diagnosis, 54.44% and 96.96% for PSP diagnosis, 87.72% and 86.41% for MSA-C diagnosis, and 55.56% and 91.55% for MSA-P diagnosis, respectively. It could correctly classify 75%(240/320) of patients. Conclusions: Characteristic metabolism patterns of brain in 18F-FDG PET/CT imaging is significant for the differential diagnosis of PD, PSP, MSA-C and MSA-P. The"diagnostic tree"model is valuable for clinical diagnosis.


Asunto(s)
Atrofia de Múltiples Sistemas , Enfermedad de Parkinson , Trastornos Parkinsonianos , Masculino , Femenino , Humanos , Enfermedad de Parkinson/diagnóstico por imagen , Fluorodesoxiglucosa F18 , Tomografía Computarizada por Tomografía de Emisión de Positrones , Atrofia de Múltiples Sistemas/diagnóstico por imagen , Atrofia de Múltiples Sistemas/metabolismo , Radiofármacos , Trastornos Parkinsonianos/diagnóstico por imagen , Trastornos Parkinsonianos/metabolismo , Encéfalo/diagnóstico por imagen , Encéfalo/metabolismo , Glucosa/metabolismo , Diagnóstico Diferencial
2.
Zhonghua Er Ke Za Zhi ; 60(7): 682-687, 2022 Jul 02.
Artículo en Chino | MEDLINE | ID: mdl-35768356

RESUMEN

Objectives: To investigate the risk factors and short-term prognosis of early pulmonary hypertension (PH) in preterm infants. Methods: A retrospective case-control study was performed in preterm infants (gestational age <32 weeks) in the neonatal intensive care unit (NICU) of the Children's Hospital, Zhejiang University School of Medicine from January 2012 to December 2019. Eighty preterm infants with a diagnosis of PH between 3 and 14 days (early PH group) were matched in gestational age and sex with the controls (1∶2) of the same period in NICU. Perinatal clinical records, complications, echocardiography and early outcomes were collected. Characteristics and outcomes were compared between the two groups with t-test, nonparametric test or Chi-square test. Multivariate Logistic regression was used to analyze the predictive factors of early PH. Results: The gestational age of the early PH group and the control group were both (27.9±1.4) weeks, and 52 (65.0%) and 104 (65.0%) were males in each group, respectively. Univariate analysis showed that birth weights were lower in the early PH group than those in the control group (1 030 (850, 1 200) vs. 1 110 (1 000, 1 278) g, Z=-3.27, P=0.001). The early PH group had higher rates of pregnancy-induced hypertension, prolonged rupture of membranes (PROM) >1 week, born by caesarean, small for gestational age (SGA), 1 and 5 min Apgar score ≤7 scores, neonatal respiratory distress syndrome (RDS) and hemodynamic significant patent ductus arteriosus (hsPDA) (12.5% (10/80) vs. 3.8% (6/160), 11.2% (9/80) vs. 3.8% (6/160), 48.8% (39/80) vs. 28.8% (46/160), 10.0% (8/80) vs. 1.9% (3/160), 70.8% (51/72) vs. 51.7% (74/143), 50.0% (36/72) vs. 20.3% (29/143), 88.8% (71/80) vs. 59.4% (95/160), 85.0% (68/80) vs. 22.5% (36/160), χ2=6.56, 5.12, 3.31, 8.05, 7.17, 20.05, 21.58, 84.84, all P<0.05). Multivariate Logistic regression analysis showed that the independent predictive factors of early PH were PROM >1 week, SGA, 5 min Apgar score ≤7 scores, nenonatal RDS and hsPDA (OR=10.40, 18.61, 4.47, 4.13, 20.10, 95%CI 1.93-56.12, 2.82-122.76, 1.91-10.46, 1.50-11.39, 8.28-48.80, all P<0.05),respectively. Infants with early PH had higher incidence of bronchopulmonary dysplasia (BPD), BPD associated PH, severe intraventricular hemorrhage (IVH), extrauterine growth retardation (EUGR), laser treatment for retinopathy of prematurity (ROP) and mortality than the controls (all P<0.05). The duration of invasive mechanical ventilation was also longer in the early PH group than that in the control group (P<0.05). Conclusions: Risk of early PH will be increased in preterm infants with PROM >1 week, SGA, 5 min Apgar score ≤7 scores, and comorbidities of nenonatal RDS and hsPDA. Early PH is associated with increased mortality, BPD, BPD associated PH, severe IVH, EUGR and laser treatment for ROP.


Asunto(s)
Displasia Broncopulmonar , Conducto Arterioso Permeable , Hipertensión Pulmonar , Enfermedades del Recién Nacido , Síndrome de Dificultad Respiratoria del Recién Nacido , Retinopatía de la Prematuridad , Displasia Broncopulmonar/complicaciones , Estudios de Casos y Controles , Hemorragia Cerebral , Niño , Femenino , Edad Gestacional , Humanos , Hipertensión Pulmonar/diagnóstico , Hipertensión Pulmonar/etiología , Lactante , Recién Nacido , Recien Nacido Prematuro , Masculino , Embarazo , Pronóstico , Estudios Retrospectivos , Factores de Riesgo
3.
J Endocrinol Invest ; 45(2): 261-273, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34455568

RESUMEN

PURPOSE: The purpose of this study is to evaluate the effectiveness and safety of liraglutide/liraglutide + metformin in overweight/obese women with polycystic ovary syndrome (PCOS). METHODS: The related literatures published until April 2021 were searched in PubMed, Cochrane Library, MEDLINE and EmBase. RESULTS: Six randomized controlled trials of 127 related articles were obtained through searching. Three articles compared liraglutide with metformin, and four articles compared liraglutide combined with metformin with metformin. Our meta-analysis suggests that liraglutide was superior to metformin only in weight loss [MD = - 2.74, 95% CI (- 4.29, - 1.18), P = 0.0006]. Compared with metformin group, the combination group had significant advantages in weight loss [MD = - 3.81, 95% CI (- 5.16, - 2.46), P < 0.001], BMI [MD = - 2.59, 95% CI (- 3.12, - 2.07), P < 0.001], waist circumference [MD = - 6.26, 95% CI (- 7.79, - 4.72), P < 0.001], fasting blood glucose [MD = - 0.59, 95% CI (- 0.74, - 0.44), P < 0.001] and fasting insulin [MD = - 1.52, 95% CI (- 2.69, - 0.35), P = 0.01], while the incidence of adverse reactions was relatively high [RR = 2.91, 95% CI (1.55, 5.46), P = 0.00009]. CONCLUSION: The present results indicate that liraglutide and metformin have the similar effects in the treatment of overweight/obese PCOS patients. Liraglutide combined with metformin is more effective than metformin in improving PCOS, but it is necessary to master the correct medication method to reduce the occurrence of adverse reactions.


Asunto(s)
Liraglutida/farmacología , Metformina/farmacología , Obesidad/tratamiento farmacológico , Síndrome del Ovario Poliquístico/tratamiento farmacológico , Sinergismo Farmacológico , Quimioterapia Combinada/efectos adversos , Quimioterapia Combinada/métodos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/etiología , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/prevención & control , Femenino , Humanos , Hipoglucemiantes/farmacología , Administración del Tratamiento Farmacológico , Obesidad/complicaciones , Obesidad/metabolismo , Síndrome del Ovario Poliquístico/complicaciones , Síndrome del Ovario Poliquístico/metabolismo , Resultado del Tratamiento
4.
Zhonghua Er Ke Za Zhi ; 59(10): 853-858, 2021 Oct 02.
Artículo en Chino | MEDLINE | ID: mdl-34587682

RESUMEN

Objective: To summarize the clinical features and therapeutic outcomes of patients with hyperinsulinemic hypoglycemia (HH) auxiliarily diagnosed by 18F-DOPA positron emission tomography (PET) CT scanning. Methods: The clinical data of 123 patients who were diagnosed with hyperinsulinemic hypoglycemia by comprehensive clinical diagnostic procedures in the Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University between January 2016 and December 2020 were retrospectively analyzed. Clinical data such as gender, age of onset, province, concurrent serum insulin level measured during hypoglycemia, lesion type of pancreas by 18F-DOPA-PET CT scanning, genetic test results, and treatment were collected successively. The clinical features and therapeutic outcomes were compared between patients with focal and diffuse pancreatic lesions. T test, Rank sum test, and χ² test were used for comparison between groups. Results: A total of 123 patients with hyperinsulinemic hypoglycemia (72 males and 51 females), whose average age of onset was 3 days (ranging from 1 day to 4 860 days), were recruited from 24 provinces. The concurrent serum insulin level was 7.1 (0.4-303.0) mU/L during hypoglycemia. 18F-DOPA-PET CT scanning identified focal lesions in 25.2% (31/123) and diffuse lesions in 74.8% (92/123) of the patients; 64.2% (79/123) of the HH cases were found to have pathogenic gene variants, in which 88.6% (70/79) were found to have KATP channel related genes (61 in ABCC8 and 9 in KCNJ11 mutations). Thirty-seven patients (17 focal and 20 diffuse) received surgical treatment with a success rate of 67.6% (25/37). The effective rate of diazoxide for children with diffuse type was significantly higher than that of children with focal group (28.3% (26/92) vs. 9.7% (3/31), χ²=10.31, P=0.001). Conclusions: 18F-DOPA-PET CT scan can improve the success rate of surgery. Comprehensive diagnosis of the etiology of hyperinsulinemic hypoglycemia by genetic analysis and 18F-DOPA-PET CT scanning can result in better treatment and prognosis.


Asunto(s)
Hiperinsulinismo Congénito , Tomografía Computarizada por Tomografía de Emisión de Positrones , Niño , Hiperinsulinismo Congénito/diagnóstico por imagen , Hiperinsulinismo Congénito/tratamiento farmacológico , Hiperinsulinismo Congénito/genética , Dihidroxifenilalanina/análogos & derivados , Femenino , Humanos , Masculino , Tomografía de Emisión de Positrones , Estudios Retrospectivos
5.
Animal ; 15(1): 100027, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33573989

RESUMEN

Lactose and somatic cell score (SCS) are major economic traits of milk. However, for many countries, they are typically not directly considered in the national genetic evaluation of Simmental cattle. This study aimed to estimate the genetic relationships between lactose, SCS, and growth traits of Simmental cattle to provide information for the national genetic evaluation of the selection of traits of this cattle population. The data of 1781 animals with 6519 records obtained over a period of 41 years (1975-2016) were collected from Xinjiang Hutubi Farm, China. The analyzed traits included 305 days of milk yield (305MY), milk fat percentage (MFP), milk protein percentage (MPP), milk lactose percentage (MLP), total solids (TS), SCS, body height (BH), body length (BL), chest girth (CG), abdominal circumference (AC), rump width (RW), rump length (RL), leg circumference (LC), and cannon circumference (CC). The multiple-trait repeatability model was adopted to estimate (co)variance components using the average information-restricted maximum likelihood method implemented using the DMU statistical package. The heritability estimates for milk components and growth traits ranged from 0.09 (SCS) to 0.51 (BH). Genetic correlations for milk components ranged from 0.03 ±â€¯0.14 (MFP and MLP) to 0.81 ±â€¯0.08 (MFP and MPP). Genetic correlation between MLP and SCS was moderate and negative (-0.50 ±â€¯0.15) compared with that among other traits. Genetic correlations between the milk components and growth traits ranged from 0.00 ±â€¯0.07 (305MY and RW) to -0.64 ±â€¯0.15 (MLP and BL). Genetic correlations of BL, LC, RW, and RL with MLP were moderate to high and negative ranging from -0.39 to -0.64. Somatic cell score showed the highest correlation with BL (0.41) followed by LC (0.21). An increase in MLP would result in an increase in 305MY or TS and a decrease in BL, LC, RW, and RL. Additionally, a decrease in SCS would occur with the selection of increased MLP and reduced BL. We conclude that selection based on easily and inexpensively measured growth traits could improve the milk quality from Simmental cattle.


Asunto(s)
Lactancia , Lactosa , Animales , Bovinos/genética , China , Femenino , Leche , Proteínas de la Leche , Fenotipo
6.
Zhonghua Yan Ke Za Zhi ; 56(5): 343-348, 2020 May 11.
Artículo en Chino | MEDLINE | ID: mdl-32450666

RESUMEN

Objective: To observe the preliminary clinical effect of intraocular lens optic capture through posterior continuous curvilinear capsulorhexis in the treatment of pediatric cataract. Methods: It was a retrospective case series study. Forty-three eyes of 28 children underwent posterior continuous curvilinear capsulorhexis with posterior chamber intraocular lens optic capture to treat cataract from June 2017 to October 2018 in Qingdao Eye Hospital. Postoperative best corrected visual acuity, diopters, intraocular pressure, the position of intraocular lens, and postoperative complications were assessed. The distribution of preoperative and postoperative best corrected visual acuity was analyzed by Fisher's exact probability test. Results: Twenty-eight patients were 14 females and 14 males aged from 2 years old to 12 years old [mean age, (7±4) years]. All intraocular lenses were successfully captured in the posterior capsule. Patients were followed-up for 6.0 to 12.0 months (mean, 8.4 months). Except 2 eyes from one uncooperative child, the distribution of preoperative and postoperative best corrected visual acuity (<0.1, 0.1-<0.3, 0.3-<0.5, ≥0.5) had a significant difference (17, 17, 4, 3 eyes vs. 4, 4, 5, 28 eyes, P<0.01). At the last postoperative follow-up visit, the mean spherical equivalent was (0.21±0.74) D. Transient intraocular hypertension occurred in 3 eyes at 1 week after surgery and was controlled with stopping the use of corticosteroid eyedrops. No visual axis opacification or intraocular lens decentration or tilt was observed during the follow-up period. No other complications such as iris synechia, secondary glaucoma, retinal detachment, and cystoid macular edema were observed. Conclusions: Posterior continuous curvilinear capsulorhexis with intraocular lens optic capture is a safe and effective technique to treat pediatric cataract. It has a significant effect on the prevention of visual axis opacification after cataract surgery in children. (Chin J Ophthalmol, 2020, 56: 343-348).


Asunto(s)
Capsulorrexis , Extracción de Catarata , Catarata , Lentes Intraoculares , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Implantación de Lentes Intraoculares , Masculino , Complicaciones Posoperatorias , Estudios Retrospectivos
7.
Eur Rev Med Pharmacol Sci ; 23(16): 6783-6790, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31486476

RESUMEN

OBJECTIVE: Traumatic arthritis is one of the most common diseases in orthopedics. LGR4 is involved in bone formation and bone development. However, the role of LGR4 in synovial cells of rats with traumatic osteoarthritis has not been reported. MATERIALS AND METHODS: Sprague Dawley (SD) rats were randomly divided into the control group and model group. The Real Time-Polymerase Chain Reaction (RT-PCR), Western blot, and Enzyme-Linked Immunosorbent Assay (ELISA) were used to analyze the expression of LGR4 in synovial tissue and synovial fluid. Synovial cells were isolated and cultured, followed by transfection of LGR4-pcDNA3.1 plasmid into cells. Cell proliferation was analyzed by MTT and EdU assay, and the Caspase-3 activity was assessed using the Caspase-3 activity kit. The secretion of the inflammatory factors interleukin-1 (IL-1), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) was detected by ELISA. NF-κB signaling pathway changes were evaluated by the Western blot. RESULTS: In the model group, LGR4 mRNA expression in synovial tissue was significantly decreased, and the secretion of LGR4 in the synovial fluid was significantly decreased compared with the control group (p<0.05). LGR4 protein expression in the synovial membrane in the model group tissue was reduced. The transfection of LGR4-pcDNA3.1 plasmid into synovial cells promoted the LGR4 expression, inhibited the proliferation of synoviocytes, increased the Caspase-3 activity, the secretion of IL-1, TNF-α, and IL-6, as well as the decreased expression of NF-κB with a statistical significance, compared with the control group (p<0.05). CONCLUSIONS: LGR4 expression is reduced in the rat model of traumatic osteoarthritis. The upregulation of LGR4 expression can inhibit the secretion of the inflammatory factors and inhibit the proliferation of the synovial cells by regulating NF-κB signaling pathway, which may alleviate the development of the joint inflammation.


Asunto(s)
Proliferación Celular , Factores Inmunológicos/inmunología , Osteoartritis/inmunología , Receptores Acoplados a Proteínas G/metabolismo , Sinoviocitos/inmunología , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Factores Inmunológicos/genética , Interleucina-1/genética , Interleucina-1/inmunología , Interleucina-6/genética , Interleucina-6/inmunología , Masculino , FN-kappa B/metabolismo , Osteoartritis/metabolismo , Osteoartritis/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Receptores Acoplados a Proteínas G/genética , Transducción de Señal , Sinoviocitos/metabolismo , Sinoviocitos/patología , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/inmunología
8.
Zhonghua Er Ke Za Zhi ; 55(10): 785-789, 2017 Oct 02.
Artículo en Chino | MEDLINE | ID: mdl-29050119

RESUMEN

Objective: To study the feasibility of (18)F-fluoro-L-dihydroxyphenylalanine positron emission tomography/Computed tomography ((18)F-DOPA PET/CT) scanning in the localization and differential diagnosing of focal versus diffuse form of pancreas lesions in patients with hyperinsulinemic hypoglycemia (HH). Method: Twenty-four patients were diagnosed with HH between January, 2016 and February, 2017 in the Department of Pediatric Endocrinology and Inherited Metabolic Diseases, Children's Hospital of Fudan University using an integrated clinical and biochemical diagnostic protocol, domestic (18)F-DOPA PET/CT imaging technique were applied after MRI and ultrasound failed to detect pancreas lesions. Pancreas (18)F-DOPA standardized uptake values (SUV) were measured, and pancreas' lesions were dually analyzed via visual method and pancreas percentage SUV method. Among these patients, 9 patients received surgical pancreatic lesion resections, the correlations among surgical outcomes, histopathological findings and (18)F-DOPA PET/CT scan results were analyzed. Result: Seven patients were detected with focal form of pancreas lesions, the mean peak of SUV was 4.7±1.7(2.6-7.1), and 17 patients were found to have diffuse form lesions after (18)F-DOPA-PET/CT scanning. Among the 24 cases, 9 patients (7 showed focal and 2 showed diffuse (18)F-DOPA PET/CT pancreatic uptake)were euglycemic without any medical support after surgery; the resected pancreatic tissue histopathological results were consistent with that of PET/CT imaging. Only one patient, who responded to medical treatment before surgery, had temporary hyperglycemia after operation. Conclusion: Domestic (18)F-DOPA PET/CT could successfully locate and differentiate the pancreatic lesions and thus improve the success of surgery.


Asunto(s)
Hiperinsulinismo Congénito/complicaciones , Dihidroxifenilalanina/análogos & derivados , Tomografía Computarizada por Tomografía de Emisión de Positrones , Niño , Diagnóstico Diferencial , Humanos , Imagen por Resonancia Magnética , Páncreas , Tomografía de Emisión de Positrones , Tomografía Computarizada por Rayos X
9.
Eur J Gynaecol Oncol ; 38(1): 106-112, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29767875

RESUMEN

PURPOSE: Cervical cancer, which is treated by radiotherapy (RT) and chemoradiotherapy (CRT), has high morbidity and mortality in women. This study aimed to identify differences in gene response to CRT and RT. MATERIALS AND METHODS: GSE3578 was downloaded from Gene Expression Omnibus including specimens from 20 RT-treated patients and 19 CRT-treated patients. Differentially expressed genes (DEGs) were identified using siggenes package in R. Protein-protein interaction (PPI) network was visualized by cytoscape. MCODE and cytoscape was used separately to mine and construct modules in the PPI network. Transcription factor (TF)-DEG and miRNA-DEG pairs were predicted and then visualized by cytoscape. RESULTS: Total 22 upregulated and 181 downregulated genes were identified in CRT samples. Several functions were enriched for these DEGs. A module involving ZNF449 and ZNF673 was mined from the PPI network of downregulated genes. In the TF-DEG regulatory networks, downregulated GATA3 (which was modulated by SPI) was also a TF, as well as upregulated CDK6 was regulated by several TFs (e.g. GATA3). Hsa-miR-17, hsa-miR-34a, hsa-miR-124, hsa-miR-I185-2-3p, hsa- 1185-1-3p, and hsa-let-7f-2-3p were identified as key miRNAs in the miRNA-DEG regulatory network. Conclu- sion: CRT might cure cervical cancer by acting on those molecules that were more sensitive to CRT than CT.


Asunto(s)
Neoplasias del Cuello Uterino/tratamiento farmacológico , Neoplasias del Cuello Uterino/radioterapia , Quimioradioterapia , Bases de Datos Genéticas , Femenino , Perfilación de la Expresión Génica , Humanos , Análisis por Micromatrices , Estudios Retrospectivos , Resultado del Tratamiento , Neoplasias del Cuello Uterino/genética
10.
J Biomech ; 49(11): 2112-2117, 2016 07 26.
Artículo en Inglés | MEDLINE | ID: mdl-26654675

RESUMEN

BACKGROUND AND PURPOSE: To quantify the relationship and to demonstrate redundancies between hemodynamic and structural parameters before and after virtual treatment with a flow diverter device (FDD) in cerebral aneurysms. METHODS: Steady computational fluid dynamics (CFD) simulations were performed for 10 cerebral aneurysms where FDD treatment with the SILK device was simulated by virtually reducing the porosity at the aneurysm ostium. Velocity and pressure values proximal and distal to and at the aneurysm ostium as well as inside the aneurysm were quantified. In addition, dome-to-neck ratios and size ratios were determined. Multiple correlation analysis (MCA) and hierarchical cluster analysis (HCA) were conducted to demonstrate dependencies between both structural and hemodynamic parameters. RESULTS: Velocities in the aneurysm were reduced by 0.14m/s on average and correlated significantly (p<0.05) with velocity values in the parent artery (average correlation coefficient: 0.70). Pressure changes in the aneurysm correlated significantly with pressure values in the parent artery and aneurysm (average correlation coefficient: 0.87). MCA found statistically significant correlations between velocity values and between pressure values, respectively. HCA sorted velocity parameters, pressure parameters and structural parameters into different hierarchical clusters. HCA of aneurysms based on the parameter values yielded similar results by either including all (n=22) or only non-redundant parameters (n=2, 3 and 4). CONCLUSION: Hemodynamic and structural parameters before and after virtual FDD treatment show strong inter-correlations. Redundancy of parameters was demonstrated with hierarchical cluster analysis.


Asunto(s)
Simulación por Computador , Hemodinámica , Aneurisma Intracraneal/terapia , Humanos , Hidrodinámica , Aneurisma Intracraneal/patología , Aneurisma Intracraneal/fisiopatología , Presión , Stents
11.
Ann N Y Acad Sci ; 984: 453-69, 2003 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-12783837

RESUMEN

We report a means for efficient and selective extraction of carbon dioxide (CO(2)) at low to medium concentration from mixed gas streams. CO(2) capture was accomplished by use of a novel enzyme-based, facilitated transport contained liquid membrane (EBCLM) reactor. The parametric studies we report explore both structural and operational parameters of this design. The structural parameters include carbonic anhydrase (CA) concentration, buffer concentration and pH, and liquid membrane thickness. The operational parameters are temperature, humidity of the inlet gas stream, and CO(2) concentration in the feed stream. The data show that this system effectively captures CO(2) over the range 400 ppm to at least 100,000 ppm, at or around ambient temperature and pressure. In a single pass across this homogeneous catalyst design, given a feed of 0.1% CO(2), the selectivity of CO(2) versus N(2) is 1,090 : 1 and CO(2) versus O(2) is 790 :1. CO(2) permeance is 4.71 x 10(-8) molm(-2) Pa(-1) sec(-1). The CLM design results in a system that is very stable even in the presence of dry feed and sweep gases.


Asunto(s)
Dióxido de Carbono/análisis , Técnicas de Química Analítica/métodos , Membranas Artificiales , Animales , Dióxido de Carbono/química , Anhidrasas Carbónicas/química , Bovinos , Relación Dosis-Respuesta a Droga , Concentración de Iones de Hidrógeno , Modelos Biológicos , Temperatura , Agua/metabolismo
12.
13.
J Am Chem Soc ; 123(24): 5768-76, 2001 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-11403611

RESUMEN

Surface lamellar decoration (SLD), surface enhanced Raman scattering (SERS) and optical second harmonic generation (SHG) experiments have been utilized to study the molecular orientation and conformation changes at a rubbed polyimide alignment-layer surface. This aromatic polyimide containing pendent cyanobiphenyl mesogens was synthesized via a polycondensation of 2,2'-bis(3,4-dicarboxy-phenyl)hexafluoropropane dianhydride (6FDA) with bis[omega-[4-(4-cyanophenyl)phenoxy]hexyl] 4,4'-diamino-2,2'-biphenyldicarboxylate (nCBBP, n = 6), abbreviated as 6FDA--6CBBP. Uniform alignment layers, possessing high pretilt angles ranging from 39 degrees to 43 degrees, have been achieved after mechanical rubbing of the polyimide thin film surface at room temperature and subsequent annealing. This is the first time that high pretilt angles have been detected to possess a negative angle (-theta(c)) with respect to the rubbing direction (i.e., opposite to the rubbing direction), considerably different from the conventional pretilt angle (theta(c)) observed along the rubbing direction. This observation is confirmed using magnetic null and SHG methods. Combined polyethylene (PE) SLD and atomic force microscopy experiments reveal that the azimuthal orientation distribution of the long axis of the edge-on PE lamellar crystals is oriented normal to the rubbing direction, indicating that the PE chains are aligned parallel to the rubbing direction. This SLD technique probes the anisotropic surface orientation of the outermost molecules of the rubbed polyimide layer. The SERS results show that prior to rubbing the surface, both the pendent cyanobiphenyls in the side chains and backbones possess nearly planar chain conformations at the polyimide surface. Mechanical rubbing causes not only tilting of the backbone moieties, such as imide-phenylene structure, but also significant conformational rearrangements of the pendent side chains at the surfaces. The molecular mechanism of this unusual alignment is due to the fact that the pendent cyanobiphenyls forms a uniformly tilted conformation on the rubbed surface, and the polar cyano groups point down toward the layer surface deduced from SHG phase measurements. This conformational rearrangement of the side chains results in the formation of fold-like bent structures on the surface, which directly leads to the long axis of cyanobiphenyls having the -theta(c) pretilt angle with respect to the rubbing direction.

14.
Phys Rev E Stat Nonlin Soft Matter Phys ; 63(5 Pt 1): 051706, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11414920

RESUMEN

Surface second harmonic generation was used to obtain approximate orientational distributions of the side chains and the adsorbed liquid crystal (LC) molecules on a rubbed side-chain polyimide surface. Both the side chains and the LC molecules appear to be well aligned in the rubbing direction but tilted away from the surface in the antirubbing direction. The latter yields a negative pretilt angle in a homogeneously aligned LC film sandwiched between two such surfaces. The side chains and the LC molecules, however, have antiparallel orientations at the surface.

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