Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
1.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(11): 1181-1187, 2023 Nov 24.
Artículo en Chino | MEDLINE | ID: mdl-37963754

RESUMEN

Objective: To investigate the role and related mechanism of ubiquitin-like protein FAT10 in the angiotensin Ⅱ (AngⅡ)-induced endothelial cell inflammatory responses. Methods: The Western blot was used to detect the protein expression of FAT10 in 16-weeks old WKY rat carotid artery, thoracic aorta artery, renal artery and vascular smooth muscle cells (VSMC), human umbilical vein endothelial cells (HUVEC) and human breast cancer cells (MDA-MB-231). The optimal concentration and stimulation time of AngⅡ on inducing the highest FAT10 in HUVEC were determined. The following plasmids were constructed: control plasmid, overexpression FAT10 plasmid (Flag-FAT10), invalid interference plasmid, and interference FAT10 plasmid (sh-FAT10). These plasmids were then transfected into HUVEC cells and divided into following groups: control group, Flag-FAT10 group, invalid interference group, and sh-FAT10 group. After culturing with 100 nmol/L AngⅡ for 36 h, the control group and the Flag-FAT10 group were treated with reactive oxygen species scavenger N-acetyl-L-cysteine ​​(NAC), the protein expression levels of the inflammatory factor monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α) were measured. Laser confocal microscopy was used to detect the generation levels of reactive oxygen species in the cells of vrious groups. Results: FAT10 was expressed in carotid artery, thoracic aorta, and renal artery of normal blood pressure rats and expressed in HUVEC, VSMC, MDA-MB-231. The expression level of FAT10 gradually increased in proportion to the increase of the time and concentration of AngⅡ stimulation in HUVEC, and the expression level of FAT10 was the highest when the HUVEC was treated with 100 nmol/L AngⅡ for 36 h (P<0.01). The protein expression level of MCP-1 (P<0.001) and TNF-α (P<0.01) was higher in AngⅡ treated HUVEC with FAT10 overexpression, while the expression level of MCP-1 and TNF-α protein was lower in AngⅡ treated HUVEC with FAT10 knockdown (all P<0.01). The level of intracellular reactive oxygen species (ROS) production was significantly increased with FAT10 overexpression (P<0.001), and the level of ROS was decreased when the expression of FAT10 was interfered (P<0.05). The increased level of MCP-1 and TNF-α proteins in FAT10 overexpressed HUVEC was reversed by NAC (all P<0.05). Conclusion: FAT10 promotes the release of inflammatory factors induced by AngⅡ in endothelial cells by increasing the level of intracellular ROS production.


Asunto(s)
Angiotensina II , Factor de Necrosis Tumoral alfa , Humanos , Ratas , Animales , Especies Reactivas de Oxígeno/metabolismo , Especies Reactivas de Oxígeno/farmacología , Células Cultivadas , Angiotensina II/farmacología , Angiotensina II/metabolismo , Factor de Necrosis Tumoral alfa/farmacología , Factor de Necrosis Tumoral alfa/metabolismo , Ratas Endogámicas WKY , Células Endoteliales de la Vena Umbilical Humana , Inflamación , Ubiquitinas/metabolismo , Ubiquitinas/farmacología
2.
Zhonghua Xin Xue Guan Bing Za Zhi ; 51(9): 951-957, 2023 Sep 24.
Artículo en Chino | MEDLINE | ID: mdl-37709711

RESUMEN

Objective: To compare the 5-year follow-up outcomes of radiofrequency catheter ablation (RFCA) combined with left atrial appendage closure (LAAC) and long-term oral anticoagulant (OAC) after RFCA in patients with atrial fibrillation. Methods: This retrospective cross-sectional study included patients with atrial fibrillation who underwent"one-stop"procedure in the First Affiliated Hospital of Ningbo University from September 2015 to December 2017 (RFCA+LAAC group). Baseline data of patients were collected. Propensity score matching at the ratio of 1∶1 was used to select patients with atrial fibrillation who took long-term OAC after RFCA (RFCA+OAC group). The maintenance rate of sinus rhythm and the incidence of adverse events during follow-up were compared between the two groups. Results: A total of 110 patients were enrolled in the RFCA+LAAC group and RFCA+OAC group, respectively. Age of patients was (67.4±8.8) years in RFCA+LAAC group, and there were 42 (38.2%) female patients. Age of patients was (67.3±7.9) years in RFCA+OAC group, and there were 47 (42.7%) female patients. The patients were followed up for mean of (5.3±1.1) years. There was no significant difference in the maintenance rate of sinus rhythm (log-rank: χ2=0.277, P=0.602) and incidence of ischemic stroke events (2.7% (3/110) vs. 4.5% (5/110), P=0.719) during follow-up between the two groups. The incidence of bleeding events (6.4% (7/110) vs. 18.2% (20/110), P=0.008) and major bleeding events (1.8% (2/110) vs. 8.2% (9/110), P=0.030) was significantly higher in the RFCA+OAC group than in the RFCA+LAAC group. Conclusion: There is no significant difference between RFCA+LAAC group and RFCA+OAC group in maintenance rate of sinus rhythm and incidence of ischemic stroke events. Patients in the RFCA+LAAC group have a lower risk of bleeding events compared to the RFCA+OAC group.


Asunto(s)
Fibrilación Atrial , Ablación por Catéter , Accidente Cerebrovascular Isquémico , Humanos , Femenino , Persona de Mediana Edad , Anciano , Masculino , Fibrilación Atrial/cirugía , Estudios Transversales , Estudios de Seguimiento , Estudios Retrospectivos , Anticoagulantes/uso terapéutico
3.
Zhonghua Xin Xue Guan Bing Za Zhi ; 50(8): 780-784, 2022 Aug 24.
Artículo en Chino | MEDLINE | ID: mdl-35982010

RESUMEN

Objective: To evaluate the feasibility and safety of the LAmbre occluder for large-diameter left atrial appendage occlusion. Methods: This study was a retrospective cohort study. Patients with large orifice of the left atrial appendage (≥31 mm) and occlusion with the LAmbre device in the Arrhythmia Center of Ningbo First Hospital were included from June 2018 to March 2020. Baseline data were collected and major perioperative complications of left atrial appendage occlusion (including death, stroke, instrumental embolism, cardiac tamponade, and major bleeding events) were recorded. Patients were followed up 45 days, 6 months and 12 months after surgery. The shunt and device-related thrombosis were recorded by esophageal cardiac ultrasound or pulmonary vein CT, and the occurrence of postoperative thromboembolism, bleeding events, death and other serious adverse events were recorded. Results: The average age and left atrial appendage ostial dimension of 32 patients (37.5% women) included in this research were (70.4±8.4) years old and (34.4±2.9) mm. The LAmbre device was successfully implanted in 31(96.9%) patients. No major complications occurred during the perioperative period. During the 12-month follow-up, pericardial tamponade occurred in 1(3.2%) patient and was recovered after treatment. There was no occluder edge shunt>5 mm in patients followed up by esophageal echocardiography. No significant peri-device leak, device-related thrombus, thromboembolism or death event has occurred. Conclusion: The LAmbre occluder may be feasible and safe for large-diameter left atrial appendage occlusion.


Asunto(s)
Apéndice Atrial , Dispositivo Oclusor Septal , Anciano , Apéndice Atrial/diagnóstico por imagen , Apéndice Atrial/cirugía , Estudios de Factibilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Dispositivo Oclusor Septal/efectos adversos , Accidente Cerebrovascular/epidemiología , Tromboembolia/etiología , Trombosis , Resultado del Tratamiento
4.
Nat Commun ; 12(1): 3645, 2021 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-34112779

RESUMEN

Understanding the competition between superconductivity and other ordered states (such as antiferromagnetic or charge-density-wave (CDW) state) is a central issue in condensed matter physics. The recently discovered layered kagome metal AV3Sb5 (A = K, Rb, and Cs) provides us a new playground to study the interplay of superconductivity and CDW state by involving nontrivial topology of band structures. Here, we conduct high-pressure electrical transport and magnetic susceptibility measurements to study CsV3Sb5 with the highest Tc of 2.7 K in AV3Sb5 family. While the CDW transition is monotonically suppressed by pressure, superconductivity is enhanced with increasing pressure up to P1 ≈ 0.7 GPa, then an unexpected suppression on superconductivity happens until pressure around 1.1 GPa, after that, Tc is enhanced with increasing pressure again. The CDW is completely suppressed at a critical pressure P2 ≈ 2 GPa together with a maximum Tc of about 8 K. In contrast to a common dome-like behavior, the pressure-dependent Tc shows an unexpected double-peak behavior. The unusual suppression of Tc at P1 is concomitant with the rapidly damping of quantum oscillations, sudden enhancement of the residual resistivity and rapid decrease of magnetoresistance. Our discoveries indicate an unusual competition between superconductivity and CDW state in pressurized kagome lattice.

5.
Zhonghua Yan Ke Za Zhi ; 56(11): 832-838, 2020 Nov 11.
Artículo en Chino | MEDLINE | ID: mdl-33152841

RESUMEN

Objective: To describe imaging signs of infraorbital nerve enlargement (IONE) and frontal nerve enlargement (FNE) in orbital lymphoproliferative diseases (LPDs), and to explore the diagnostic value and differential diagnostic role of the signs. Methods: A retrospective case series study. The data of 222 cases (262 eyes) of LPDs and 95 cases (134 eyes) of inflammatory pseudotumors (IPs) pathologically confirmed by the Peking University People's Hospital and the Third Medical Center of the Chinese PLA General Hospital from January 2013 to December 2018 were analyzed. The LPDs were lymphoma (including atypical lymphoid hyperplasia) in 91 cases (110 eyes) and reactive lymphoid hyperplasia (RLH) in 131 cases (152 eyes). The patients with LPD included 101 males and 121 females, aged (58±17) years, and the patients with IP included 44 males and 51 females, aged (49±21) years. All patients underwent orbital CT or MRI with T1 weighted imaging, T2 weighted imaging and enhanced T1 weighted imaging scanning. Slice thickness was 3 mm. In the coronal CT or MRI, the criterion for determining IONE was the inferior orbital nerve diameter greater than the optic nerve, and the criterion for determining FNE was the forehead nerve diameter equal to or greater than the optic nerve. The pathological types and imaging features of nerve enlargement were recorded. The incidence rates of different pathological types were compared using chi-square test. Results: The enlarged nerves showed homogeneous soft tissue density on CT images, accompanied with enlarged bony infraorbital nerve grooves (foramina). MRI showed moderate signals of T1 and T2 weighted imaging, with clear boundaries and obvious enhancement, which could spread to the pterygopalatine fossa and the cranial cavity. The accompanying images included the enlargement of lacrimal glands or extraocular muscles, intraorbital mass or sinuses opacity. The IONE and/or FNE were found in 12 patients with LPD, but were not found in any patients with IP. The difference was statistically significant (12/222 vs. 0/95, χ²=5.337, P=0.021). Among the cases with nerve enlargement, there were 2 cases of diffuse large B cell lymphoma and 10 cases of RLH (2/91 vs. 10/131, χ²=3.103, P=0.078), as well as 7 cases of IgG4-related ophthalmic disease (IgG4-ROD) and 3 cases of non-IgG4-ROD (7/28 vs. 3/103, χ2=15.232, P=0.000). Conclusions: Lymphoma and RLH can express IONE and/or FNE, in which the IgG4-ROD is the most common and specific type. CT and MRI scans can show enlarged nerves and accompanying signs. Neural thickening can also be applied as a discrimination marker of LPDs and IPs. (Chin J Ophthalmol, 2020, 56: 832-838).


Asunto(s)
Enfermedad Relacionada con Inmunoglobulina G4 , Enfermedades Orbitales , Adulto , Anciano , Femenino , Humanos , Inmunoglobulina G , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Enfermedades Orbitales/diagnóstico por imagen , Estudios Retrospectivos
7.
Radiat Prot Dosimetry ; 184(3-4): 444-447, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31330000

RESUMEN

In order to investigate the influence of the static electricity on the measurement using passive radon detector, detectors were charged at the surface of chamber and its CR-39 elements respectively on purpose before the exposure in this study. The results of in-chamber experiments revealed that the static electricity would lead to critical influence on measurement especially when the CR-39 elements were negatively charged. The static charge would remain for several ten hours, which result in more significant influence on the short-term measurement.


Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Monitoreo de Radiación/métodos , Radón/análisis , Electricidad Estática , Dosis de Radiación
8.
Radiat Prot Dosimetry ; 184(3-4): 435-439, 2019 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-31095343

RESUMEN

For more effective testing the abatement effects of radon exposure with different counter measures, an air-conditioned laboratory room was reformed as an experimental chamber. Based on the well control and real time monitoring of concentrations of 222Rn, its attached and unattached progeny and their size distributions, the chamber could provide three modules corresponding to ventilation, source reduction and filtration for abating radon exposure. Preliminary results showed that the chamber was useful for testing the abatement effect of indoor radon exposure.


Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Contaminación del Aire Interior/análisis , Exposición a la Radiación/análisis , Monitoreo de Radiación/métodos , Hijas del Radón/análisis , Radón/análisis , Filtración , Humanos , Ventilación
9.
Phys Rev E ; 96(1-1): 012103, 2017 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29347150

RESUMEN

We study the thermal phase transition of the fourfold degenerate phases (the plaquette and single-stripe states) in the two-dimensional frustrated Ising model on the Shastry-Sutherland lattice using Monte Carlo simulations. The critical Ashkin-Teller-like behavior is identified both in the plaquette phase region and the single-stripe phase region. The four-state Potts critical end points differentiating the continuous transitions from the first-order ones are estimated based on finite-size-scaling analyses. Furthermore, a similar behavior of the transition to the fourfold single-stripe phase is also observed in the anisotropic triangular Ising model. Thus, this work clearly demonstrates that the transitions to the fourfold degenerate states of two-dimensional Ising antiferromagnets exhibit similar transition behavior.

11.
Oncogenesis ; 5(6): e237, 2016 Jun 27.
Artículo en Inglés | MEDLINE | ID: mdl-27348267

RESUMEN

Ras-Association Domain Family 10 (RASSF10) is the last identified member of the RASSF family. The functional characteristics of this new gene in human cancers remain largely unclear. Here, we examined RASSF10 for the biological functions and related molecular mechanisms in hepatocellular carcinoma (HCC). We found that RASSF10 is expressed in normal human liver tissue, but is silenced or down-regulated in 62.5% (5/8) of HCC cell lines. The mean expression level of RASSF10 was significantly lower in primary HCCs compared with their adjacent normal tissues (P<0.005, n=52). The promoter methylation contributes to the inactivation of RASSF10 as demonstrated by bisulfite genomic sequencing and demethylation treatment analyses. Transgenic expression of RASSF10 in silenced HCC cell lines suppressed cell viability, colony formation and inhibited tumor growth in nude mice (QGY7703, P<0.01; HepG2, P<0.05). Furthermore, RASSF10 was shown to induce the cell accumulation in G1 phase with the increase of p27, as well as the decrease of cyclinD1 and CDK2/CDK4. Over-expression of RASSF10 also inhibited HCC cells migration (P<0.01) or invasion (P<0.05). Adhesion genes array revealed that Matrix Metalloproteinase 2 (MMP2) was a downstream effector of RASSF10. RASSF10 acting as a tumor suppressor to inhibit HCC invasion partially mediated by Focal Adhesion Kinase or p38 MAPK to decrease the accumulation of MMP2. Our study suggests that RASSF10 acts as a tumor suppressor for HCC.

12.
Genet Mol Res ; 15(2)2016 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-27323179

RESUMEN

Ginkgolide B has been known to inhibit cell apoptosis by modulating multiple cytokines and plays an important role in neuroprotection. Signal transducer and activator of transcription 1 (STAT1) has been studied in a spinal cord injury (SCI) model. However, the role of Ginkgolide B in SCI treatment remains unclear. This study investigated the potential mechanism of Ginkgolide B using an SCI rat model. SD rats were used to generate an SCI model followed by Ginkgolide B injection (4 mg/kg) for 14 days. Spinal cord tissue samples were examined using hematoxylin and eosin (H&E) staining. The expression of STAT1 was determined by western blot. Using a dyskinesia scale, intervention with Ginkgolide B significantly decreased the severity of SCI. H&E staining revealed less nuclear condensation and cell necrosis in SCI rats after treatment with Ginkgolide B. STAT1 expression was significantly increased in SCI model rats, but was lower after Ginkgolide B treatment. Therefore, Ginkgolide B can effectively inhibit STAT1 expression and alleviate SCI.


Asunto(s)
Ginkgólidos/farmacología , Lactonas/farmacología , Factor de Transcripción STAT1/antagonistas & inhibidores , Factor de Transcripción STAT1/biosíntesis , Traumatismos de la Médula Espinal/tratamiento farmacológico , Animales , Apoptosis/efectos de los fármacos , Modelos Animales de Enfermedad , Fármacos Neuroprotectores/uso terapéutico , Ratas , Ratas Sprague-Dawley , Recuperación de la Función/efectos de los fármacos , Traumatismos de la Médula Espinal/metabolismo , Traumatismos de la Médula Espinal/patología
13.
J Phys Condens Matter ; 28(34): 346004, 2016 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-27356040

RESUMEN

In this work, we study the magnetization behaviors of the classical Ising model on the triangular lattice using Monte Carlo simulations, and pay particular attention to the effect of further-neighbor interactions. Several fascinating spin states are identified to be stabilized in certain magnetic field regions, respectively, resulting in the magnetization plateaus at 2/3, 5/7, 7/9 and 5/6 of the saturation magnetization M S, in addition to the well-known plateaus at 0, 1/3 and 1/2 of M S. The stabilization of these interesting orders can be understood as the consequence of the competition between Zeeman energy and exchange energy.

14.
Phys Rev E ; 93(3): 032114, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-27078299

RESUMEN

In this work, we investigate the phase transitions and critical behaviors of the frustrated J(1)-J(2)-J(3) Ising model on the square lattice using Monte Carlo simulations, and particular attention goes to the effect of the second-next-nearest-neighbor interaction J(3) on the phase transition from a disordered state to the single stripe antiferromagnetic state. A continuous Ashkin-Teller-like transition behavior in a certain range of J(3) is identified, while the four-state Potts-critical end point [J(3)/J(1)](C) is estimated based on the analytic method reported in earlier work [Jin, Sen, and Sandvik, Phys. Rev. Lett. 108, 045702 (2012)]. It is suggested that the interaction J(3) can tune the transition temperature and in turn modulate the critical behaviors of the frustrated model. Furthermore, it is revealed that an antiferromagnetic J(3) can stabilize the staggered dimer state via a phase transition of strong first-order character.

15.
Radiat Prot Dosimetry ; 170(1-4): 311-4, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-26940440

RESUMEN

For more accurate assessments of the occupational exposure to radon for miners, the individual monitoring was conducted by using an improved passive integrating (222)Rn monitor. A total of 120 miners in 3 different kinds of mines were monitored throughout a year. The results showed that the individual exposure to radon significantly varied with types of mines and work. Compared with the exposure to coal miners, the exposure to copper miners was much higher. Furthermore, it was found that the exposure might be overestimated if the environmental (222)Rn monitored by the passive integrating monitors was used for assessment. The results indicate that the individual monitoring of radon is necessary for an accurate assessment of radon exposure to miners, and radon exposure to non-uranium miners should also be assessed from the viewpoint of radiation protection.


Asunto(s)
Minería , Enfermedades Profesionales/prevención & control , Exposición Profesional/análisis , Protección Radiológica/métodos , Radón/análisis , Uranio/análisis , Contaminantes Atmosféricos , Carbón Mineral , Monitoreo del Ambiente/métodos , Humanos , Neoplasias Pulmonares , Estaciones del Año , Recursos Humanos
16.
Neoplasma ; 62(6): 846-54, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26458323

RESUMEN

RNA transcripts, which do not encode proteins, have received considerable attention in recent years. These non-coding RNAs are classified into two groups: small non-coding RNAs and long non-coding RNAs (lncRNAs). Increasing evidence suggests that lncRNAs are emerging as key regulators in many biological processes. However, knowledge of the underlying mechanisms whereby they act is still limited. Here, we try to elucidate the way that lncRNAs function in the context of DNA, RNA and protein interaction networks. It is noteworthy that lncRNA and another type of non-coding RNA microRNA (miRNA) may 'talk' to each other more frequently than ever expected. Additionally, lncRNAs display aberrant expression profiles in different kinds of cancers, with their potential roles in carcinogenesis and cancer metastasis. We summarize the effect of some cancer related lncRNAs upon tumor biological events, including cell proliferation, apoptosis, invasion and metastasis. Finally, we focus on the clinical value of lncRNAs, considering their potential application in cancer diagnosis, prognosis and therapeutic intervention.

17.
Reprod Domest Anim ; 50(5): 793-9, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26280670

RESUMEN

Astaxanthin is an extremely common antioxidant scavenging reactive oxygen species (ROS) and blocking lipid peroxidation. This study was conducted to investigate the effects of astaxanthin supplementation on oocyte maturation, and development of bovine somatic cell nuclear transfer (SCNT) embryos. Cumulus-oocyte complexes were cultured in maturation medium with astaxanthin (0, 0.5, 1.0, or 1.5 mg/l), respectively. We found that 0.5 mg/l astaxanthin supplementation significantly increased the proportion of oocyte maturation. Oocytes cultured in 0.5 mg/l astaxanthin supplementation were used to construct SCNT embryos and further cultured with 0, 0.5, 1.0 or 1.5 mg/l astaxanthin. The results showed that the supplementation of 0.5 mg/l astaxanthin significantly improved the proportions of cleavage and blastulation, as well as the total cell number in blastocysts compared with the control group, yet this influence was not concentration dependent. Chromosomal analyses revealed that more blastomeres showed a normal chromosomal complement in 0.5 mg/l astaxanthin treatment group, which was similar to that in IVF embryos. The methylation levels located on the exon 1 of the imprinted gene H19 and IGF2, pluripotent gene OCT4 were normalized, and global DNA methylation, H3K9 and H4K12 acetylation were also improved significantly, which was comparable to that in vitro fertilization (IVF) embryos. Moreover, we also found that astaxanthin supplementation significantly decreased the level of lipid peroxidation. Our findings showed that the supplementation of 0.5 mg/l astaxanthin to oocyte maturation medium and embryo culture medium improved oocyte maturation, SCNT embryo development, increased chromosomal stability and normalized the epigenetic modifications, as well as inhibited overproduction of lipid peroxidation.


Asunto(s)
Antioxidantes/farmacología , Bovinos/embriología , Epigénesis Genética/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Técnicas de Transferencia Nuclear/veterinaria , Acetilación , Animales , Blastocisto/citología , Blastocisto/fisiología , Recuento de Células/veterinaria , Reprogramación Celular/efectos de los fármacos , Clonación de Organismos/veterinaria , Metilación de ADN , Técnicas de Cultivo de Embriones/veterinaria , Embrión de Mamíferos/efectos de los fármacos , Desarrollo Embrionario/efectos de los fármacos , Desarrollo Embrionario/genética , Fertilización In Vitro , Histonas/metabolismo , Técnicas de Maduración In Vitro de los Oocitos/veterinaria , Datos de Secuencia Molecular , Análisis de Secuencia/veterinaria , Xantófilas/farmacología
18.
Radiat Prot Dosimetry ; 167(1-3): 223-7, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26065703

RESUMEN

In order to explain the distribution of natural radiation level in the Asia, in situ measurements of dose rate in air due to terrestrial gamma radiation have been conducted in a total of 21 islands that belong to Ryukyu Islands (Ryukyu Archipelago), subtropical rejoin of southwest Japan. Car-borne surveys have also been carried out in Okinawa-jima, the biggest island of the archipelago. Based on the results for these measurements, arithmetic mean, the maximum and the minimum of the dose rates at 1 m in height from the unpaved soil ground in the archipelago were estimated to be 47, 165 and 8 nGy h(-1), respectively. A comparative study of car-borne data obtained prior to and subsequent to the 2011 Fukushima nuclear accident, as for Okinawa-jima, indicated that the nuclear accident has no impact on the environmental radiation at the present time.


Asunto(s)
Accidente Nuclear de Fukushima , Rayos gamma , Monitoreo de Radiación/métodos , Ceniza Radiactiva/análisis , Contaminantes Radiactivos del Suelo/administración & dosificación , Radiación de Fondo , Islas , Japón , Dosis de Radiación , Monitoreo de Radiación/instrumentación , Conteo por Cintilación , Clima Tropical
19.
Radiat Prot Dosimetry ; 167(1-3): 251-4, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25944963

RESUMEN

For more accurate assessment of the enhanced external exposure to dwellers caused by decorative stones, based on a model room and different decorative conditions, the 3-D distributions of indoor gamma dose rates were computed by the Monte Carlo simulations, and a new model was established to estimate the extra gamma dose rate at the centre of the room in this study. For verification of the simulation results, the gamma radiation was both instantaneously and cumulatively measured in a test room. The results showed that both the gamma dose rate at the centre of the room and the distribution of indoor gamma radiation were in general agreement with the simulated ones.


Asunto(s)
Contaminación del Aire Interior/estadística & datos numéricos , Materiales de Construcción/estadística & datos numéricos , Rayos gamma , Modelos Estadísticos , Exposición a la Radiación/estadística & datos numéricos , Monitoreo de Radiación/métodos , Contaminación del Aire Interior/análisis , Algoritmos , Simulación por Computador , Materiales de Construcción/análisis , Método de Montecarlo , Dispersión de Radiación
20.
Radiat Prot Dosimetry ; 167(1-3): 121-5, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25920784

RESUMEN

In this study, based on the electrostatic integrating radon monitor (EIRM) developed by Iida et al., a new type of EIRM with the allyl glycol carbonate (CR-39) as alpha-particle detector was developed for outdoor radon measurements. Besides using the CR-39 to replace the cellulose nitrate film as alpha-particle detector, the electrode and the setting place of the CR-39 were also optimally designed based on the simulation results of the electric field and the detection efficiency. The calibration factor of the new EIRM was estimated to be 0.136±0.002 tracks cm(-2) (Bq m(-3) h)(-1), with the lower detection limit of 0.6 Bq m(-3) for a 2-month exposure. Furthermore, both the battery and the dry agent were also replaced to protect the environment. The results of intercomparison and field experiments showed that the performances of the new EIRM were much better than the original one. It suggests that the new type of ERIM is more suitable for large-scale and long-term outdoor radon surveys.


Asunto(s)
Contaminantes Radiactivos del Aire/análisis , Partículas alfa , Electrodos , Tecnología de Fibra Óptica/instrumentación , Monitoreo de Radiación/instrumentación , Radón/análisis , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Dosis de Radiación , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Electricidad Estática , Integración de Sistemas
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA