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1.
Chemphyschem ; 25(3): e202300851, 2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38088520

RESUMEN

As a material with high specific surface area and excellent chemical stability, graphene exhibited remarkable adsorption and separation performance as well as a wide range of potential applications. The graphene layer played a significant role in influencing gas transmission. In this study, we employed molecular dynamics simulation to investigate the diffusion characteristics and local structures of a mixed system consisting of CH4 , CO2 , SO2 and H2 O. Additionally, we further examined the transformation of the behavior of these mixtures within graphene layers. The order of diffusion coefficients of the four molecules without graphene was H2 O>SO2 >CO2 ≫CH4 . However, in the double-layer graphene, the order changed to CH4 >CO2 ≫H2 O>SO2 . Higher temperatures and lower pressures were found to facilitate gas diffusion. Temperature and pressure had great effects on the local structures of CH4 , CO2 and SO2 , while their impact on H2 O was limited due to the extensive network of hydrogen bonds formed by H2 O molecules. The statistical results of average coordination number revealed that CH4 tended to aggregate with itself, whereas CO2 and SO2 exhibited a tendency to aggregate with H2 O. The graphene structure enhanced the separation and transportation of CH4 from mixed systems.

2.
Environ Sci Technol ; 58(26): 11447-11458, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38899977

RESUMEN

Mine tailings are extremely oligotrophic environments frequently contaminated with elevated As and Sb, making As(III) and Sb(III) oxidation potentially important energy sources for the tailing microbiome. Although they have been proposed to share similar metabolic pathways, a systemic comparison of the As(III) and Sb(III) oxidation mechanisms and energy utilization efficiencies requires further elucidation. In this study, we employed a combination of physicochemical, molecular, and bioinformatic analyses to compare the kinetic and genetic mechanisms of As(III) and Sb(III) oxidation as well as their respective energy efficiencies for fueling the key nutrient acquisition metabolisms. Thiobacillus and Rhizobium spp. were identified as functional populations for both As(III) and Sb(III) oxidation in mine tailings by DNA-stable isotope probing. However, these microorganisms mediated As(III) and Sb(III) oxidation via different metabolic pathways, resulting in preferential oxidation of Sb(III) over As(III). Notably, both As(III) and Sb(III) oxidation can facilitate nitrogen fixation and phosphate solubilization in mine tailings, with Sb(III) oxidation being more efficient in powering these processes. Thus, this study provided novel insights into the microbial As(III) and Sb(III) oxidation mechanisms and their respective nutrient acquisition efficiencies, which may be critical for the reclamation of mine tailings.


Asunto(s)
Oxidación-Reducción , Antimonio/metabolismo , Minería , Arsénico/metabolismo
3.
Environ Sci Technol ; 58(28): 12441-12453, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-38900020

RESUMEN

Degraded tailings generated by the mining of metal ores are major environmental threats to the surrounding ecosystems. Tailing reclamation, however, is often impeded due to adverse environmental conditions, with depleted key nutrients (i.e., nitrogen (N) and phosphorus (P)) and elevated sulfur and metal(loid) concentrations. Formation of biocrusts may significantly accelerate nutrient accumulation and is therefore an essential stage for tailing reclamation. Although suggested to play an important role, the microbial community composition and key metabolisms in biocrusts remain largely unknown and are therefore investigated in the current study. The results suggested that sulfur and arsenic oxidation are potential energy sources utilized by members of predominant biocrust bacterial families, including Beijerinckiaceae, Burkholderiaceae, Hyphomicrobiaceae, and Rhizobiaceae. Accordingly, the S and As oxidation potentials are elevated in biocrusts compared to those in their adjacent tailings. Biocrust growth, as proxied by chlorophyll concentrations, is enhanced in treatments supplemented with S and As. The elevated biocrust growth might benefit from nutrient acquisition services (i.e., nitrogen fixation and phosphorus solubilization) fueled by microbial sulfur and arsenic oxidation. The current study suggests that sulfur- and arsenic-oxidizing microorganisms may play important ecological roles in promoting biocrust formation and facilitating tailing reclamation.


Asunto(s)
Arsénico , Minería , Oxidación-Reducción , Azufre , Arsénico/metabolismo , Azufre/metabolismo , Bacterias/metabolismo , Fósforo , Microbiología del Suelo , Biodegradación Ambiental
4.
Hum Reprod ; 38(7): 1390-1398, 2023 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-37140151

RESUMEN

STUDY QUESTION: What is the effect of defects in the manchette protein IQ motif-containing N (IQCN) on sperm flagellar assembly? SUMMARY ANSWER: Deficiency in IQCN causes sperm flagellar assembly defects and male infertility. WHAT IS KNOWN ALREADY: The manchette is a transient structure that is involved in the shaping of the human spermatid nucleus and protein transport within flagella. Our group recently reported that the manchette protein IQCN is essential for fertilization. Variants in IQCN lead to total fertilization failure and defective acrosome structure phenotypes. However, the function of IQCN in sperm flagellar assembly is still unknown. STUDY DESIGN, SIZE, DURATION: Fifty men with infertility were recruited from a university-affiliated center from January 2014 to October 2022. PARTICIPANTS/MATERIALS, SETTING, METHODS: Genomic DNA was extracted from the peripheral blood samples of all 50 individuals for whole-exome sequencing. The ultrastructure of the spermatozoa was assessed by transmission electron microscopy. Computer-assisted sperm analysis (CASA) was used to test the parameters of curvilinear velocity (VCL), straight-line velocity (VSL), and average path velocity (VAP). An Iqcn knockout (Iqcn-/-) mouse model was generated by CRISPR-Cas9 technology to evaluate sperm motility and the ultrastructure of the flagellum. Hyperactivation and sperm fertilizing ability were assessed in a mouse model. Immunoprecipitation followed by liquid chromatography-mass spectrometry was used to detect IQCN-binding proteins. Immunofluorescence was used to validate the localization of IQCN-binding proteins. MAIN RESULTS AND THE ROLE OF CHANCE: Biallelic variants in IQCN (c.3913A>T and c.3040A>G; c.2453_2454del) were identified in our cohort of infertile men. The sperm from the affected individuals showed an irregular '9 + 2' structure of the flagellum, which resulted in abnormal CASA parameters. Similar phenotypes were observed in Iqcn-/- male mice. VSL, VCL, and VAP in the sperm of Iqcn-/- male mice were significantly lower than those in Iqcn+/+ male mice. Partial peripheral doublet microtubules (DMTs) and outer dense fibers (ODFs) were absent, or a chaotic arrangement of DMTs was observed in the principal piece and end piece of the sperm flagellum. Hyperactivation and IVF ability were impaired in Iqcn-/- male mice. In addition, we investigated the causes of motility defects and identified IQCN-binding proteins including CDC42 and the intraflagellar transport protein families that regulate flagellar assembly during spermiogenesis. LIMITATIONS, REASONS FOR CAUTION: More cases are needed to demonstrate the relation between IQCN variants and phenotypes. WIDER IMPLICATIONS OF THE FINDINGS: Our findings expand the genetic and phenotypic spectrum of IQCN variants in causing male infertility, providing a genetic marker for sperm motility deficiency and male infertility. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (81974230 and 82202053), the Changsha Municipal Natural Science Foundation (kq2202072), the Hunan Provincial Natural Science Foundation (2022JJ40658), and the Scientific Research Foundation of Reproductive and Genetic Hospital of CITIC-Xiangya (YNXM-202114 and YNXM-202201). No conflicts of interest were declared. TRIAL REGISTRATION NUMBER: N/A.


Asunto(s)
Infertilidad Masculina , Espermatozoides , Animales , Humanos , Masculino , Ratones , Infertilidad Masculina/genética , Infertilidad Masculina/metabolismo , Semen/metabolismo , Motilidad Espermática/genética , Cola del Espermatozoide/metabolismo , Espermatozoides/metabolismo , Espermatozoides/patología
5.
J Chem Phys ; 159(4)2023 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-37486058

RESUMEN

As biomolecules vibrate and rotate in the terahertz band, the biological effects of terahertz electromagnetic fields have drawn considerable attention from the physiological and medical communities. Ion channels are the basis of biological electrical signals, so studying the effect of terahertz electromagnetic fields on ion channels is significant. In this paper, the effect of a terahertz electromagnetic field with three different frequencies, 6, 15, and 25 THz, on the Kv1.2 potassium ion channel was investigated by molecular dynamics simulations. The results show that an electromagnetic field with a 15 THz frequency can significantly enhance the permeability of the Kv1.2 potassium ion channel, which is 1.7 times higher than without an applied electric field. By analyzing the behavior of water molecules, it is found that the electromagnetic field with the 15 THz frequency shortens the duration of frozen and relaxation processes when potassium ions pass through the channel, increases the proportion of the direct knock-on mode, and, thus, enhances the permeability of the Kv1.2 potassium ion channel.

6.
J Acoust Soc Am ; 154(4): 2440-2452, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37850838

RESUMEN

Topological elastic wave metamaterials have shown significant advantages in manipulating wave propagation and realizing localized modes. However, topological properties of most mechanical metamaterials are difficult to change because of structural limitations. This work proposes the elastic wave metamaterials with double coupled chains and active control, in which band inversion and topological interface modes can be achieved by flexibly tuning negative capacitance circuits. Finite element simulations and experiments are performed to demonstrate the topological interface modes, which show good agreements with the theoretical results. This research seeks to provide effective strategies for the design and application of topological elastic wave metamaterials.

7.
Int J Mol Sci ; 25(1)2023 Dec 28.
Artículo en Inglés | MEDLINE | ID: mdl-38203598

RESUMEN

Potassium (K) channels show the highest variability and most frequent alterations in expression in many tumor types, and modulation of K+ channels may represent a new window for cancer therapy. In previous work, we found that a terahertz (THz) field incident along the z-axis with a frequency of 51.87 THz increased the ion flux through K+ channels. In practice, it is difficult to ensure that the incident electromagnetic (EM) wave is strictly parallel to the direction of channel ion flow. In this paper, we found by changing the direction of the applied electric field that the EM wave of a specific frequency has the largest ion flux when the incident direction is along the ion flow, and the smallest ion flux when the incident direction is perpendicular to the ion flow, and that overall the EM wave of this frequency enhances the ion flow of the K+ channel. Changes in the direction of the applied field at a specific frequency affect the stability of the φ dihedral angle of the GLY77 residue and alter the ion permeation mechanism in the selectivity filter (SF) region, thus affecting the ion flux. Therefore, this frequency can be used to modulate K+ fluxes by THz waves to cause rapid apoptosis in potassium-overloaded tumor cells. This approach consequently represents an important tool for the treatment of cancer and is expected to be applied in practical therapy.


Asunto(s)
Apoptosis , Electricidad , Potasio
8.
Int J Mol Sci ; 24(12)2023 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-37373419

RESUMEN

In this paper, the influence of external terahertz electromagnetic fields with different frequencies of 4 THz, 10 THz, 15 THz, and 20 THz on the permeability of the Kv1.2 voltage-gated potassium ion channel on the nerve cell membrane was studied using the combined model of the "Constant Electric Field-Ion Imbalance" method by molecular dynamics. We found that although the applied terahertz electric field does not produce strong resonance with the -C=O groups of the conservative sequence T-V-G-Y-G amino acid residue of the selective filter (SF) of the channel, it would affect the stability of the electrostatic bond between potassium ions and the carbonyl group of T-V-G-Y-G of SF, and it would affect the stability of the hydrogen bond between water molecules and oxygen atoms of the hydroxyl group of the 374THR side chain at the SF entrance, changing the potential and occupied states of ions in the SF and the occurrence probability of the permeation mode of ions and resulting in the change in the permeability of the channel. Compared with no external electric field, when the external electric field with 15 THz frequency is applied, the lifetime of the hydrogen bond is reduced by 29%, the probability of the "soft knock on" mode is decreased by 46.9%, and the ion flux of the channel is activated by 67.7%. Our research results support the view that compared to "direct knock-on", "soft knock-on" is a slower permeation mode.


Asunto(s)
Campos Electromagnéticos , Canales de Potasio con Entrada de Voltaje , Canales de Potasio con Entrada de Voltaje/metabolismo , Simulación de Dinámica Molecular , Iones/metabolismo , Permeabilidad , Potasio/metabolismo , Canal de Potasio Kv.1.2/química , Canal de Potasio Kv1.5/metabolismo
9.
J Acoust Soc Am ; 151(3): 1449, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35364921

RESUMEN

In this work, solitary wave solutions of particle mechanical metamaterials are studied, in which the mass-in-mass structure with local resonators is considered. The Hertzian contact theory is used to describe adjacent particles in a precompressed granular chain. The governing wave equations are decoupled, and the expressions of bright, dark, and peaked solitary waves are derived, respectively. According to the results, both the wave velocity and prestress can affect the propagation of solitary waves. The amplitudes of bright and peaked solitary waves are smaller when a larger prestress is applied, which are different from the dark solitons. Furthermore, the wave widths become larger as the prestress increases.

10.
Int J Mol Sci ; 24(1)2022 Dec 29.
Artículo en Inglés | MEDLINE | ID: mdl-36613998

RESUMEN

Ion transport molecules are involved in many physiological and pathological processes and are considered potential targets for cancer treatment. In the large family of ion transport molecules, potassium (K) ion channels, as surface-expressed proteins, show the highest variability and most frequent expression changes in many tumor types. The key to exploring the permeation of K+ through potassium channels lies in the conserved sequence TVGYG, which is common in the selectivity filter (SF) region of all potassium channels. We found that the K+ flux significantly increased with the help of a specific frequency terahertz electromagnetic wave (51.87 THz) in the KcsA channel using a molecular dynamics combined model through the combined simulation of the constant electric field method and ion imbalance method. This frequency has the strongest absorption peak in the infrared spectrum of -C=O groups in the SF region. With the applied electric field of 51.87 THz, the Y78 residue at the S1 site of the SF has a smaller vibration amplitude and a more stable structure, which enables the K+ to bind closely with the carbonyl oxygen atoms in the SF and realize ion conduction in a more efficient direct Coulomb knock-on.


Asunto(s)
Simulación de Dinámica Molecular , Canales de Potasio , Canales de Potasio/metabolismo , Potasio/metabolismo , Proteínas Bacterianas/metabolismo
11.
Am J Gastroenterol ; 116(Suppl 1): S3, 2021 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37461931

RESUMEN

BACKGROUND: The prevalence of cannabis use has been increasing in the United States in recent years. We examined the prevalence and predictors of cannabis use disorder among IBD hospitalizations and its effect on length of stay. METHODS: Using the 2017 National Inpatient Sample, cannabis use disorder was identified using ICD-10-CM code F12.xxx in adult IBD patients. Other variables of interest included age, sex, race, Crohn's disease (vs. ulcerative colitis), region, metropolitan status, zip code household income, primary insurance, and length of stay. Multivariate logistic and Poisson regressions were used in statistical analysis. RESULTS: Of the 17,857 IBD hospitalizations, 565 (3.1%) had cannabis use disorder. Patients with cannabis use disorder were younger (mean ± standard deviation [years]: 35.1 ± 11.8 vs. 45.6 ± 18.1), less likely female (32.7% vs. 54.1%), more likely African American (24.8% vs. 13.9%), and more likely Crohn's disease (72.0% vs. 62.2%) (all p < 0.001). There were also significant differences by region, income, and insurance. Multivariate logistic regression confirmed age (odds ratio [95% confidence interval]: 0.964 [0.957, 0.971]), female (0.444 [0.369, 0.531]), African American (1.405 [1.124, 1.750]), and Crohn's disease (1.363 [1.126, 1.657]) as predictors of cannabis use disorder. There was no association between cannabis use disorder and length of stay, confirmed in multivariate Poisson regression. CONCLUSION: Young age, male sex, African American race, and Crohn's disease were positively associated with cannabis use disorder in IBD hospitalizations. There was no effect of cannabis use disorder on length of stay.

12.
J Acoust Soc Am ; 150(6): 4343, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34972279

RESUMEN

Cloaking invisibility is a novel technique that prevents the object from being detected in the background field. The development of new artificial materials and structures promotes the emergence of new achievements in cloaking research. In this work, a broadband square cloaking configuration of elastic wave metamaterial plate is designed and fabricated by the external active control system. The approximate parameters of the flexural wave cloak can be obtained by the coordinate transformation and achieved by alternating layers of the Acrylonitrile Butadiene Styrene (ABS), polydimethylsiloxane (PDMS), and piezoelectric (PZT) patches. With the introduction of active control systems, the square cloak has a wide effective frequency range. The simulation and experimental results show that the square cloak of flexural waves exhibits a good invisible performance in the frequency region of 500-2200 Hz. Compared to the structure without active control systems, the frequency region 2200-2750 Hz is extended for the active cloak. The design and fabrication of the broadband cloak is wished to be helpful during the practical engineering.

13.
J Acoust Soc Am ; 150(2): 891, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34470290

RESUMEN

In this investigation, the bandgaps and nonreciprocal transmission of the nonlinear piezoelectric phononic crystal and elastic wave metamaterial are studied. Analytical solutions for the wave motion equations with the electro-mechanical coupling are obtained. According to the continuous conditions, the stop bands and transmission coefficients of both fundamental wave and second harmonic are derived by the stiffness matrix method. Some particular examples are presented to show the nonreciprocal transmission of the nonlinear elastic waves. Additionally, nonlinear ultrasonic experiments are applied to verify the theoretical analyses and numerical simulations. This work is intended to be helpful in the design and fabrication of devices of the elastic wave diode with piezoelectric materials.

14.
J Acoust Soc Am ; 148(6): 3722, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33379886

RESUMEN

In this paper, a piezoelectric cloaking mechanism is proposed, which makes the enclosed piezomagnetic cylinder invisible to elastic shear horizontal (SH) waves. Based on the scattering cancellation technique, the piezoelectric cloaking mechanism and dynamic stress concentration factor (DSCF) is obtained by the plane wave expansion method. A nonlinear ray trajectory equation for SH waves is derived based on the nonlinear transformation. Furthermore, piezoelectric effects on both cloaking mechanism and dynamic stress concentration are analyzed. The numerical results show that the scattering cancellation can be attributed to the cloak density, and the piezoelectric property can enhance the object's invisibility. The piezoelectric cloaking design can be applied to reduce the DSCF in some frequency regions, which means that it can change the stress distribution. It means that piezoelectric scattering cancellation can enhance both the cloaking results and structural strength of the mechanical metamaterials. This study is expected to have significance for the development and design of elastic wave metamaterials.

15.
Fish Physiol Biochem ; 45(4): 1367-1376, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31209688

RESUMEN

The main purpose of this study was to investigate the distribution of acid phosphatase (ACP), alkaline phosphatase (ALP), non-specific esterase (NSE), peroxidase (POD), and mucous cells in the intestine of the koi carp Cyprinus carpio var. koi. ACP activity was located in the striated border, enterocytes, and lamina propria of the anterior and middle intestines. The ACP activity in the anterior intestine was higher than that in the middle and posterior intestines. ALP existed in the striated border of enterocytes and lamina propria, serosa, muscular layer, and the junction between muscular layer and submucosa layer of the intestine. The ALP activity in the anterior intestine was higher than that in the middle and posterior intestines. NSE activity was localized in the cytoplasm of enterocytes in the whole intestine, and the middle intestine showed the lower NSE activity than the anterior and posterior intestines. POD activity was localized in the blood cells of the lamina propria and cytoplasm of enterocytes in all intestinal segments. The POD activity among the anterior, middle, and posterior intestines was non-significantly different. Alcian blue periodic acid-Schiff histochemical results revealed three types of mucous cells in the intestine. The total number of mucous cells and percentage of type I cells among the anterior, middle, and posterior intestines were non-significantly different. The percentage of the type II cells was the highest in the posterior intestine, while the lowest in the anterior intestine. The percentage of the type III cells was the highest in the anterior intestine, while the lowest in the posterior intestine.


Asunto(s)
Fosfatasa Ácida/metabolismo , Fosfatasa Alcalina/metabolismo , Carboxilesterasa/metabolismo , Carpas/metabolismo , Mucosa Intestinal/enzimología , Peroxidasa/metabolismo , Animales , Moco/citología , Moco/enzimología
17.
Cancer Cell Int ; 17: 103, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-29162985

RESUMEN

BACKGROUND: Renal cell carcinoma (RCC) is the most common kidney cancer, accounting for approximately 80-90% of all primary kidney cancer. Treatment for patients with advanced RCC remains unsatisfactory. Rare cancer stem cells (CSCs) are proposed to be responsible for failure of current treatment. METHODS: OncoLnc was used as a tool for interactively exploring survival correlations. Gene manipulation and expression analysis were carried out using siRNA, RT-PCR and Western blotting. Wound healing and invasion assays were used for phenotypical characterization. Aldefluor assay and FACS sorting Sphere culture were used to determine the "stemness" of CSCs. Co-Immunoprecipitation (Co-IP) was used to examine the interaction between OCT4 and CBFA2T2. Student's t-test and Chi square test was used to analyze statistical significance. RESULTS: CBFA2T2 expression can significantly predict the survival of RCC patients. Knocking-down of CBFA2T2 can inhibit cell migration and invasion in RCC cells in vitro, and reduce ALDHhigh CSCs populations. CBFA2T2 expression is necessary for sphere-forming ability and cancer stem cells marker expression in RCC cell lines. CONCLUSIONS: Our data suggest that CBFA2T2 expression correlates with aggressive characteristics of RCC and CBFA2T2 is required for maintenance of "stemness" through regulation of stem cells factors, thereby highlighting CBFA2T2 as a potential therapeutic target for RCC treatment.

18.
Digestion ; 93(2): 132-8, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26636320

RESUMEN

BACKGROUND/AIMS: The benefits of colonoscopy in reducing colorectal cancer (CRC) risk for patients over 75 years are controversial. We aimed to determine whether colonoscopy use is associated with a decreased risk of CRC in patients 76-85 years old in the United States (US). PATIENTS AND METHODS: All patients in the Medicare 5% random sample of the Surveillance, Epidemiology and End Results-Medicare linked database 76-85 years old at outpatient colonoscopy between January 1, 1998 and December 31, 2002 were identified. Using the Kaplan-Meier method, we estimated the cumulative incidence of CRC in the above-mentioned colonoscopy group and compared with the control group of patients without colonoscopy. All patients were followed until diagnosis of CRC or carcinoma in situ, death or December 31, 2005. The multivariate Cox proportional hazards model was used in statistical analysis. CRC was separated by location into distal vs. proximal CRC in subgroup analysis. RESULTS: Of 5,701 patients in the colonoscopy group, 37 (0.65%) patients were diagnosed with CRC, compared to 379 (1.55%) out of 24,437 patients in the control group (p < 0.001). The cumulative incidences of distal and proximal CRC were lower in the colonoscopy group compared to those in the control group (5-year distal CRC: 0.26 vs. 0.77%; 5-year proximal CRC: 0.43 vs. 0.79%, both p < 0.05). In multivariate Cox regression, colonoscopy was associated with decreased risk of all CRC (hazard ratio ((HR) 0.42, 95% CI 0.28-0.65), distal CRC (HR 0.36, 95% CI 0.18-0.70), and proximal CRC (HR 0.53, 95% CI 0.30-0.92)). CONCLUSION: Among patients 76-85 years old in the United States, colonoscopy use was associated with decreased risks of both distal and proximal CRC, with a smaller risk reduction in distal colon. Due to inherent limitations associated with our retrospective design, future prospective studies are needed to validate these findings.


Asunto(s)
Carcinoma in Situ/epidemiología , Carcinoma/epidemiología , Colonoscopía , Neoplasias Colorrectales/epidemiología , Detección Precoz del Cáncer/estadística & datos numéricos , Anciano , Anciano de 80 o más Años , Carcinoma/diagnóstico , Carcinoma in Situ/diagnóstico , Neoplasias Colorrectales/diagnóstico , Femenino , Humanos , Incidencia , Almacenamiento y Recuperación de la Información , Estimación de Kaplan-Meier , Masculino , Medicare , Análisis Multivariante , Modelos de Riesgos Proporcionales , Programa de VERF , Estados Unidos/epidemiología
19.
Digestion ; 94(3): 176-180, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27871069

RESUMEN

BACKGROUND AND AIMS: In the United States, little is known about the rates of interval upper gastrointestinal (GI) cancer (possibly missed out) after an esophagogastroduodenoscopy (EGD) is performed. Data from non-US studies reported interval cancer rates of 7-26%. We aimed to study the rate and predictors of interval upper GI cancers in the United States. METHODS: Using the random 5% sample of Medicare beneficiaries in the Surveillance, Epidemiology, and End Results-Medicare linked database, we identified patients diagnosed with esophageal or gastric cancer during 2000-2007. EGD performed within 36 months prior to cancer diagnosis was identified using CPT codes. Cancers diagnosed 6-36 months after EGD were defined as interval (vs. detected) cancers. The chi-square test and the multivariate logistic model were used in statistical analysis. RESULTS: Of 751 patients diagnosed with upper GI cancer, 52 patients (6.9%) were diagnosed with interval cancers 6-36 months after EGD. The rate of interval cancers was 5.5% (31/568) for gastroenterologists and 11.5% (21/183) for non-gastroenterologists (p < 0.01). In multivariate logistic regression, EGDs performed by gastroenterologists (vs. non-gastroenterologists: OR 0.46, 95% CI 0.25-0.83) and those in inpatient setting (vs. outpatient: OR 0.53, 95% CI 0.28-0.997) were associated with a lower likelihood of interval cancers. Sensitivity analyses limited to outpatient EGDs or interval cancers 6-30 months after EGDs led to similar results. CONCLUSIONS: The rate of interval cancers after EGD is the same as the rate of colonoscopy among Medicare patients in the United States. EGDs performed by gastroenterologists and in in-patient settings were associated with a lesser likelihood of interval cancers.


Asunto(s)
Colonoscopía , Endoscopía del Sistema Digestivo , Neoplasias Esofágicas/epidemiología , Neoplasias Gástricas/epidemiología , Factores de Edad , Anciano , Anciano de 80 o más Años , Bases de Datos Factuales , Detección Precoz del Cáncer/métodos , Neoplasias Esofágicas/patología , Femenino , Gastroenterólogos , Humanos , Masculino , Medicare , Estudios Retrospectivos , Factores Sexuales , Neoplasias Gástricas/patología , Factores de Tiempo , Estados Unidos/epidemiología
20.
Chaos ; 25(6): 063108, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26117102

RESUMEN

The nonlinear dynamical equations are established for the double layered viscoelastic nanoplates (DLNP) subjected to in-plane excitation based on the nonlocal theory and von Kármán large deformation theory. The extended high dimensional homoclinic Melnikov method is employed to study the homoclinic phenomena and chaotic motions for the parametrically excited DLNP system. The criteria for the homoclinic transverse intersection for both the asynchronous and synchronous buckling cases are proposed. Lyapunov exponents and phase portraits are obtained to verify the Melnikov-type analysis. The influences of structural parameters on the transverse homoclinic orbits and homoclinic bifurcation sets are discussed for the two buckling cases. Some novel phenomena are observed in the investigation. It should be noticed that the nonlocal effect on the homoclinic behaviors and chaotic motions is quite remarkable. Hence, the small scale effect should be taken into account for homoclinic and chaotic analysis for nanostructures. It is significant that the nonlocal effect on the homoclinic phenomena for the asynchronous buckling case is quite different from that for the synchronous buckling case. Moreover, due to the van der Walls interaction between the layers, the nonlocal effect on the homoclinic behaviors and chaotic motions for high order mode is rather tiny under the asynchronous buckling condition.

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