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1.
J Oral Rehabil ; 45(3): 240-249, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29314191

ABSTRACT

Current bibliometric analyses of the evolving trends in research scope category across different time periods using the H-classics method in implantology are considerably limited. The purpose of this study was to identify the classic articles in implantology to analyse bibliometric characteristics and associated factors in implantology for the past four decades. H-Classics in implantology were identified within four time periods between 1977 and 2016, based on the h-index from the Scopus® database. For each article, the principal bibliometric parameters of authorship, geographic origin, country origin, and institute origin, collaboration, centralisation, article type, scope of study and other associated factors were analysed in four time periods. A significant increase in mean numbers of authors per H-Classics was found across time. Both Europe and North America were the most productive region/country and steadily dominated this field in each time period. Collaborations of author, internationally and inter-institutionally had significantly increased across time. A significant decentralisation in authorships, institutes and journals was noted in past four decades. The journal of Clinical Oral Implant Researches has raised its importance for almost 30 years (1987-2016). Research on Complications, peri-implant infection/pathology/therapy had been increasing in production throughout each period. This is the first study to evaluate research trends in implantology in the past 40 years using the H-classics method, which through analysing via principle bibliometric characteristics reflected a historical perspective on evolutionary mainstream in the field. Prominence of research regarding complications may forecast innovative advancements in future.


Subject(s)
Biomedical Research , Dental Implantation , Periodontics , Publishing/standards , Bibliometrics , Databases, Factual , Dental Implants , Humans
2.
J Periodontal Res ; 52(5): 922-929, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28464230

ABSTRACT

OBJECTIVES: Chronic periodontitis is a bone destructive inflammatory disease with an adverse impact on general health and suggested underlying factors in common with osteoporosis. A few studies have examined the possible relationship between chronic periodontitis and osteoporosis; however, the results remain inconclusive. This longitudinal follow-up study investigated the possible risk of patients with chronic periodontitis to present osteoporosis by using a population-based national health insurance data set in Taiwan. MATERIAL AND METHODS: A random sample consisting of 1 million individuals was collected from Taiwan's national health insurance data set. From the sample, a total of 29 463 patients with newly diagnosed periodontitis from 2002 to 2008 were recruited and compared with a matched cohort of 58 926 patients without periodontitis. All patients were tracked until an osteoporosis diagnosis, or death, until the end of 2011. Associated factors, such as gender, age and comorbidities were examined. Cox proportional-hazards regression was performed to examine the risk of osteoporosis for patients with or without periodontitis. RESULTS: Within the 6-year follow-up period, the incidence rates of osteoporosis in the periodontitis cohort and comparison group were 2.72 and 1.66 per 1000 person-years, respectively. Mild, moderate and severe periodontitis were found to have 1.56, 2.09 and 2.08 times the risk of osteoporosis respectively compared to patients without periodontitis. Log-rank analysis revealed that patients with periodontitis had significantly higher cumulative incidence rates of osteoporosis than the control group (P<.0001). CONCLUSION: This study found that patients with periodontitis had a higher risk of being diagnosed with osteoporosis.


Subject(s)
Chronic Periodontitis/complications , Chronic Periodontitis/epidemiology , Osteoporosis/complications , Osteoporosis/epidemiology , Adult , Aged , Coronary Artery Disease/epidemiology , Diabetes Mellitus/epidemiology , Female , Follow-Up Studies , Gout/epidemiology , Humans , Hyperlipidemias/epidemiology , Hypertension/epidemiology , Longitudinal Studies , Male , Middle Aged , Population Surveillance , Propensity Score , Proportional Hazards Models , Renal Insufficiency, Chronic/epidemiology , Risk Assessment , Stroke/enzymology , Taiwan/epidemiology
3.
ACS Appl Mater Interfaces ; 8(11): 7363-9, 2016 Mar 23.
Article in English | MEDLINE | ID: mdl-26927820

ABSTRACT

Graphene and its composites are widely investigated as supercapacitor electrodes due to their large specific surface area. However, the severe aggregation and disordered alignment of graphene sheets hamper the maximum utilization of its surface area. Here we report an optimized structure for supercapacitor electrode, i.e., the vertical graphene sheets, which have a vertical structure and open architecture for ion transport pathway. The effect of morphology and orientation of vertical graphene on the performance of supercapacitor is examined using a combination of model calculation and experimental study. Both results consistently demonstrate that the vertical graphene electrode has a much superior performance than that of lateral graphene electrode. Typically, the areal capacitances of a vertical graphene electrode reach 8.4 mF/cm(2) at scan rate of 100 mV/s; this is about 38% higher than that of a lateral graphene electrode and about 6 times higher than that of graphite paper. To further improve its performance, a MnO2 nanoflake layer is coated on the surface of graphene to provide a high pseudocapacitive contribution to the overall areal capacitance which increases to 500 mF/cm(2) at scan rate of 5 mV/s. The reasons for these significant improvements are studied in detail and are attributed to the fast ion diffusion and enhanced charge storage capacity. The microscopic manipulation of graphene electrode configuration could greatly improve its specific capacitance, and furthermore, boost the energy density of supercapacitor. Our results demonstrate that the vertical graphene electrode is more efficient and practical for the high performance energy storage device with high power and energy densities.

4.
Analyst ; 138(11): 3201-8, 2013 Jun 07.
Article in English | MEDLINE | ID: mdl-23591328

ABSTRACT

A highly selective, sensitive, and stable non-enzymatic glucose sensor based on Ni hydroxide modified nitrogen-incorporated nanodiamonds (Ni(OH)2-NND) was developed. The sensor was fabricated by e-beam evaporation of a thin Ni film on NND followed by the growth of Ni(OH)2 using an electrochemical process. It was found that the Ni film thickness greatly affects the morphology and electro-catalytic activity of the as-synthesized electrode for non-enzymatic glucose oxidation. Owing to its nanostructure characteristics, the best sensor fabricated by 150 nm Ni deposition showed two wide response ranges, namely, 0.02-1 mM and 1-9 mM, with sensitivities of 3.20 and 1.41 mA mM(-1) cm(-2), respectively, and a detection limit of 1.2 µM (S/N = 3). The sensor also showed good long-term stability as well as high selectivity in the presence of interferences such as ascorbic acid, acetaminophen, and uric acid. This finding reveals the possibility of exploiting the NND as an electrochemical biosensor platform where high performance addressable sensor arrays could be built.


Subject(s)
Chemistry Techniques, Analytical/instrumentation , Glucose/analysis , Hydroxides/chemistry , Nanodiamonds/chemistry , Nickel/chemistry , Nitrogen/chemistry , Artifacts , Catalysis , Electrochemistry , Electrodes , Glucose/chemistry , Oxidation-Reduction
5.
Ann Oncol ; 24(7): 1754-1761, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23524864

ABSTRACT

BACKGROUND: Trastuzumab has been approved for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric carcinoma; however, relatively little is known about the role of HER2 in the natural history of this disease. PATIENTS AND METHODS: Patients enrolled in the INT-0116/SWOG9008 phase III gastric cancer clinical trial with available tissue specimens were retrospectively evaluated for HER2 gene amplification by FISH and overexpression by immunohistochemistry (IHC). The original trial was designed to evaluate the benefit of postoperative chemoradiation compared with surgery alone. RESULTS: HER2 gene amplification rate by FISH was 10.9% among 258 patients evaluated. HER2 overexpression rate by IHC was 12.2% among 148 patients evaluated, with 90% agreement between FISH and IHC. There was a significant interaction between HER2 amplification and treatment with respect to both disease-free survival (DFS) (P = 0.020) and overall survival (OS) (P = 0.034). Among patients with HER2-non-amplified cancers, treated patients had a median OS of 44 months compared with 24 months in the surgery-only arm (P = 0.003). Among patients with HER2-amplified cancers, there was no significant difference in survival based on treatment arm. HER2 status was not a prognostic marker among patients who received no postoperative chemoradiation. CONCLUSION: Patients lacking HER2 amplification benefited from treatment as indicated by both DFS and OS. CLINICAL TRIAL: INT-0116/SWOG9008 phase III.


Subject(s)
Adenocarcinoma/genetics , Esophageal Neoplasms/genetics , Esophagogastric Junction/pathology , Gene Amplification , Receptor, ErbB-2/genetics , Stomach Neoplasms/genetics , Adenocarcinoma/mortality , Adenocarcinoma/therapy , Adult , Aged , Aged, 80 and over , Antimetabolites, Antineoplastic/therapeutic use , Chemoradiotherapy, Adjuvant , Clinical Trials, Phase III as Topic , Disease-Free Survival , Esophageal Neoplasms/mortality , Esophageal Neoplasms/therapy , Female , Fluorouracil/therapeutic use , Gastrectomy , Gene Expression , Humans , Kaplan-Meier Estimate , Male , Middle Aged , Prognosis , Randomized Controlled Trials as Topic , Receptor, ErbB-2/metabolism , Retrospective Studies , Stomach Neoplasms/mortality , Stomach Neoplasms/therapy , Treatment Outcome , Young Adult
6.
Eur J Clin Microbiol Infect Dis ; 30(11): 1365-9, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21479532

ABSTRACT

The usefulness of mec-associated dru typing in the epidemiological analysis of methicillin-resistant Staphylococcus aureus (MRSA) isolated in Malaysia was investigated and compared with pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and spa and SCCmec typing. The isolates studied included all MRSA types in Malaysia. Multilocus sequence type ST188 and ST1 isolates were highly clonal by all typing methods. However, the dru typing of ST239 isolates produced the clearest discrimination between SCCmec IIIa and III isolates, yielding more subtypes than any other method. Evaluation of the discriminatory power for each method identified dru typing and PFGE as the most discriminatory, with Simpson's index of diversity (SID) values over 89%, including an isolate which was non-typeable by spa, but dru-typed as dt13j. The discriminatory ability of dru typing, especially with closely related MRSA ST239 strains (e.g., Brazilian and Hungarian), underscores its utility as a tool for the epidemiological investigation of MRSA.


Subject(s)
Bacterial Typing Techniques/methods , Methicillin-Resistant Staphylococcus aureus/classification , Staphylococcal Infections/microbiology , Anti-Bacterial Agents/pharmacology , Cluster Analysis , Confidence Intervals , DNA, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field , Genotype , Humans , Malaysia/epidemiology , Methicillin Resistance/genetics , Methicillin-Resistant Staphylococcus aureus/genetics , Methicillin-Resistant Staphylococcus aureus/isolation & purification , Microbial Sensitivity Tests , Molecular Epidemiology , Multilocus Sequence Typing , Repetitive Sequences, Nucleic Acid/genetics , Sequence Analysis, DNA , Staphylococcal Infections/epidemiology , Staphylococcal Infections/genetics
7.
Biosens Bioelectron ; 25(4): 877-82, 2009 Dec 15.
Article in English | MEDLINE | ID: mdl-19775885

ABSTRACT

C-reactive protein (CRP) is a potential biomarker whose elevated levels in humans determine cardiovascular disease risk and inflammation. In this study, we have developed a novel capacitive biosensor for detection of CRP-antigen using capacitor with interdigitated gold (GID) electrodes on nanocrystalline diamond (NCD) surface. The NCD surface served as a dielectric layer between the gold electrodes. GID-surface was functionalized by antibodies and the immobilization was confirmed by Fourier transform spectroscopy (FT-IR) and contact angle measurements. The CRP-antigen detection was performed by capacitive/dielectric-constant measurements. The relaxation time and polarizability constants were estimated using Cole-Cole model. Our results showed that the relaxation time constant (tau) of only CRP-antibody was within 10(-16)-10(-13)s, which was increased to 10(-11)s after the incubation with CRP-antigen, suggesting that the CRP-antigen was captured by the antibodies on GID-surface. In addition, polarizability constant (m) of CRP was also increased upon incubation with increasing concentration of CRP-antigen. Our results showed that the response of GID-NCD-based capacitive biosensor for CRP-antigen was dependent on both concentration (25-800ng/ml) as well as frequency (50-350MHz). Furthermore, using optimized conditions, the GID-NCD based capacitive biosensor developed in this study can potentially be used for detection of elevated levels of protein risk markers in suspected subjects for early diagnosis of disease.


Subject(s)
Biosensing Techniques/instrumentation , Blood Chemical Analysis/instrumentation , C-Reactive Protein/analysis , Cardiovascular Diseases/blood , Cardiovascular Diseases/diagnosis , Electrochemistry/instrumentation , Biomarkers/blood , Electric Capacitance , Equipment Design , Equipment Failure Analysis , Humans , Reproducibility of Results , Sensitivity and Specificity
8.
Eur J Cancer Care (Engl) ; 16(4): 390-1, 2007 Jul.
Article in English | MEDLINE | ID: mdl-17587366

ABSTRACT

Sentinel node biopsy using patent blue dye in breast cancer is a well-documented procedure to assess the axillary status. We presented an unusual and previously unreported complication of simple blue angioedema over bilaterally periorbital tissue after blue dye injection.


Subject(s)
Angioedema/chemically induced , Coloring Agents/adverse effects , Eyelid Diseases/chemically induced , Rosaniline Dyes/adverse effects , Sentinel Lymph Node Biopsy/methods , Axilla/surgery , Breast Neoplasms/pathology , Female , Humans , Lymphatic Vessels , Middle Aged
9.
J Cardiothorac Vasc Anesth ; 15(4): 451-4, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11505348

ABSTRACT

OBJECTIVE: To determine if endotoxin core antibody (EndoCAb) from the serum of cardiac surgical patients neutralizes endotoxin in an ex vivo biologic assay. DESIGN: Prospective blinded cohort study. SETTING: Academic medical center. PARTICIPANTS: Patients (n = 203) undergoing cardiac surgery. INTERVENTIONS: Sera were obtained from patients preoperatively. MEASUREMENTS AND MAIN RESULTS: EndoCAb levels were determined by enzyme-linked immunosorbent assay. Sera were incubated for 15 minutes at 37 degrees C with varying concentrations of endotoxin from a clinically relevant bacterium (Escherichia coli serotype O18), then tested for the presence of endotoxin activity using the validated Limulus amebocyte lysate assay. Median (interquartile range) IgM and IgG EndoCAb levels were 118 median units (range, 31 to 259 median units) and 208 median units (range, 108 to 401 medium units). Increasing levels of IgM EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). Increasing levels of IgG EndoCAb were associated with increased neutralization of endotoxin (p < 0.0001). An additive effect of IgM and IgG EndoCAb levels on endotoxin neutralization was observed without evidence of synergistic or plateau effects. EndoCAb levels did not completely predict serum neutralization capacity. CONCLUSION: Anti-EndoCAbs of both classes (IgM and IgG) were able to neutralize lipopolysaccharide from a clinically relevant bacterium in an ex vivo model. Neither Igm nor IgG appeared to be more capable of neutralization in this model. These antibodies did not completely predict neutralization capacity; other endogenous factors in human serum must be capable of lipopolysaccharide neutralization.


Subject(s)
Antibodies, Bacterial/blood , Cardiac Surgical Procedures , Endotoxins/immunology , Enzyme-Linked Immunosorbent Assay , Escherichia coli/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Limulus Test , Lipopolysaccharides/immunology , Neutralization Tests , Prospective Studies
10.
Eur Arch Otorhinolaryngol ; 257(5): 242-6, 2000.
Article in English | MEDLINE | ID: mdl-10923935

ABSTRACT

Since nitric oxide (NO) can be involved in multiple physiological and pathological functions, we evaluated its possible involvement and that of peroxynitrite in the pathogenesis of rhinitis. Inferior nasal turbinates were obtained from allergic rhinitis and nonallergic rhinitis patients during corrective nasal surgery. The expressions of the inducible form of nitric oxide synthase (iNOS) and the production of peroxynitrite and its metabolite 3-nitrotyrosine were examined by immunohistochemistry in consecutive tissue sections. Each section (or tissue compartment) was given a score of 0-4 according to the labeling intensity seen, with the highest number representing the highest labeling intensity. The results showed that iNOS expression was present mainly in the mucosal epithelium, vascular endothelium, and submucosal glands. A significant difference was only observed in the labeling scores of glandular tissues of the allergic group, which had a higher iNOS labeling score. We also found that sections with a higher iNOS level did not necessarily exhibit a higher 3-nitrotyrosine labeling intensity. These data suggest that iNOS-derived NO may have a role in the pathophysiology of rhinitis, especially the glandular function of allergic nasal mucosa. Moreover, our findings suggest that the production of peroxynitrite in rhinitis patients is not dependent on the level of iNOS alone.


Subject(s)
Nasal Mucosa/pathology , Nitric Oxide Synthase/metabolism , Rhinitis, Allergic, Perennial/pathology , Rhinitis/pathology , Tyrosine/analogs & derivatives , Adolescent , Adult , Enzyme Induction/physiology , Female , Humans , Immunoenzyme Techniques , Male , Middle Aged , Nitrates/metabolism , Turbinates/pathology , Tyrosine/metabolism
11.
Zhonghua Yi Xue Za Zhi (Taipei) ; 63(5): 377-83, 2000 May.
Article in English | MEDLINE | ID: mdl-10862447

ABSTRACT

BACKGROUND: As an integral part of the contemporary vestibular testing battery, computerized vestibular rotational testing provides physiologic stimuli and quantitative evaluation of the vestibulo-ocular reflex function of the horizontal semicircular canals. Clinically, it is most commonly used in the sinusoidal harmonic acceleration test (SHAT) and velocity step test. Because the results for a given subject may vary when tested using different facilities, the purpose of this study is to establish the normative data for our laboratory. METHODS: Fifty-six normal subjects underwent the SHAT and velocity step test. Three parameters of SHAT--gain, phase and symmetry--were measured and recorded at 0.02, 0.05, 0.09 and 0.10 Hz. In the velocity step test, the three parameters of postrotatory nystagmus-time constant, maximum slow component eye velocity and directional preponderance were measured and recorded. RESULTS: The means +/- standard deviations of gain in the SHAT were 0.47 +/- 0.16 at 0.02 Hz, 0.50 +/- 0.16 at 0.05 Hz, 0.50 +/- 0.16 at 0.09 Hz and 0.53 +/- 0.17 at 0.10 Hz. The coefficient of variation for SHAT gain was 0.32. The time constant means and standard deviations in the velocity step test were 13.44 +/- 3.53 and 13.52 +/- 3.69 for clockwise and counterclockwise rotations, respectively. CONCLUSIONS: We conclude that computerized rotational vestibular testing is precise.


Subject(s)
Vestibule, Labyrinth/physiology , Adolescent , Adult , Diagnosis, Computer-Assisted , Female , Humans , Male , Reference Values , Rotation
12.
Health Phys ; 78(5): 507-10, 2000 May.
Article in English | MEDLINE | ID: mdl-10772023

ABSTRACT

The intrinsic thermoluminescent response to ultraviolet radiation of CaF2:Dy phosphor is enhanced by pre-irradiation high-temperature annealing treatment. The thermoluminescent response is stabilized by adding a medium temperature annealing treatment after the previous annealing. The experimental results show that the annealing treatment of 1 h 850 degrees C high-temperature annealing followed by 1 h 350 degrees C medium-temperature annealing is the optimum treatment to have high thermoluminescent response and good stability. The results also show that (1) the thermoluminescent response to 253.7 nm ultraviolet radiation is increased and stabilized, (2) the thermoluminescent sensitivity and glow curve distribution to 235.7 nm ultraviolet radiation are retained, and (3) the thermoluminescent response to 253.7 nm ultraviolet is linear from 3 to 1 x 10(3) Jm(-2), but there is no linear response with respect to 365 nm ultraviolet.


Subject(s)
Health Physics , Radiation Monitoring , Ultraviolet Rays , Calcium Fluoride , Humans , Radiation Injuries/prevention & control , Ultraviolet Rays/adverse effects
13.
Zhongguo Yi Liao Qi Xie Za Zhi ; 23(1): 30-3, 1999 Jan.
Article in Chinese | MEDLINE | ID: mdl-12583035

ABSTRACT

An ionization chamber for automatic exposure controlling used in X ray diagnosis machine was developped, and its characteristics were measured and researched. The electrodes of measuring field were made of carbon, such couldn't leave it's imaging on the film. In order to increase the ionization efficiency and decrease the thickness and electric capacity between electrodes, the chamber was constructed in multilayers. The chamber we developed can be fixed in different x ray machines convenientlly, there is a fine linearity between it's signal output and the exposures, the beam quality response is uniform and output-timing response is also good.


Subject(s)
Air Ionization , Atmosphere Exposure Chambers , Radiography/instrumentation , Electrodes , Equipment Design
14.
Ear Nose Throat J ; 76(6): 404-7, 1997 Jun.
Article in English | MEDLINE | ID: mdl-9210809

ABSTRACT

Angioedema is a rare but potentially lethal adverse effect when associated with upper airway obstruction. Sporadic cases of angioedema secondary to angiotensin converting enzyme inhibitors (ACEI) have been reported in the literature. The overall incidence is around 0.1% to 0.2%, and the time of onset is usually during the first week of ACEI therapy. Late-onset angioedema secondary to treatment with ACEIs is much more frequent than appreciated, and is largely unrecognized because of the absence of temporal correlation between ACEI therapy and the development of angioedema. Since angioedema may progress to upper airway obstruction, otolaryngologists must be aware of this association. Most importantly, late-onset angioedema should alert the clinician to discontinue the ACEI immediately to prevent further morbidity. This report presents an example of late-onset angioedema which was precipitated by taking a double dose of captopril incidentally. The case is discussed, and the literature, pathophysiology and treatment of angioedema are reviewed.


Subject(s)
Airway Obstruction/complications , Airway Obstruction/etiology , Angioedema/complications , Angioedema/etiology , Angiotensin-Converting Enzyme Inhibitors/adverse effects , Captopril/adverse effects , Age of Onset , Angiotensin-Converting Enzyme Inhibitors/administration & dosage , Captopril/administration & dosage , Dose-Response Relationship, Drug , Female , Humans , Middle Aged
15.
Appl Radiat Isot ; 46(5): 293-5, 1995 May.
Article in English | MEDLINE | ID: mdl-7581287

ABSTRACT

Spa water samples taken from hot and cold springs throughout Taiwan were analyzed for waterborne radon concentrations using electret ion chambers. The highest radon concentration was detected at Yangmingshan National Park, where it is closed to the action level of 11.0 kBq m-3. Next comes a sea-water hot spring at Green Isle on the east coast of Taiwan. The spa water used by the nearby inhabitants may increase the indoor radon concentration by a factor of two in extreme cases.


Subject(s)
Fresh Water/analysis , Radon/analysis , Environmental Monitoring , Taiwan , Temperature
16.
Health Phys ; 68(1): 100-4, 1995 Jan.
Article in English | MEDLINE | ID: mdl-7989185

ABSTRACT

222Rn concentrations in some Taiwanese hot spring spa waters have been monitored using commercially available electret ion chambers (EIC). The use of two EIC units for measuring radon concentrations in the air phase and voltage dependent correction factors for subtracting gamma contributions resulted in improved accuracy.


Subject(s)
Radiation Monitoring , Radon/analysis , Water Pollutants, Radioactive/analysis , Taiwan
17.
Health Phys ; 66(5): 557-64, 1994 May.
Article in English | MEDLINE | ID: mdl-8175363

ABSTRACT

Naturally occurring radon and thoron progeny are the most interfering nuclides in the aerosol monitoring system. The high background and fluctuation of natural radioactivity on the filter can cause an error message to the aerosol monitor. A theoretical model was applied in the simulation of radon and thoron progeny behavior in the environment and on the filter. Results show that even a small amount of airborne nuclides on the filter could be discriminated by using the beta:alpha activity ratio instead of gross beta or alpha counting. This method can increase the sensitivity and reliability of real-time aerosol monitoring.


Subject(s)
Air Pollutants, Radioactive , Environmental Monitoring , Radon Daughters
18.
BMJ ; 307(6901): 443, 1993 Aug 14.
Article in English | MEDLINE | ID: mdl-8374463
19.
Health Phys ; 64(6): 613-9, 1993 Jun.
Article in English | MEDLINE | ID: mdl-8491617

ABSTRACT

Solid-state alpha-track detectors using cellulose nitrate films were used to measure the radon exhalation rates from building materials. The radon flux emitted from the surface of the building material was measured by placing an inverted cup on the top of the building material. Cellulose nitrate film was placed within the cup. Tracks due to alpha particles from radon that migrate from the building material into the air space in the cup were registered on the cellulose nitrate film. The films were etched in a solution consisting of 10(-3) m3 2.5 N NaOH solution. A spark counter or microscope was used to record the tracks appearing on the cellulose nitrate film. The average exhalation rate of radon was obtained by means of a simple mathematical approach that can be used to estimate the maximum possible radon concentration in a closed room due to building materials alone. Infiltration and ventilation effects were excluded in this work. This new technique and simple approach can be used to establish the data base for average radon exhalation rates from all available building materials and walls or floors. The maximum indoor radon concentration can be estimated from the measured average radon exhalation rate by using this simplified model.


Subject(s)
Air Pollution, Indoor/analysis , Air Pollution, Radioactive/analysis , Construction Materials , Radon/analysis , Taiwan
20.
Health Phys ; 64(1): 74-8, 1993 Jan.
Article in English | MEDLINE | ID: mdl-8416219

ABSTRACT

Natural radiation in houses built with black schist slabs located at an altitude of 1,000 m in the mountainous southern part of Taiwan were investigated by studying the naturally occurring radionuclides present in the black schist. Both indoor and outdoor radon concentrations were monitored. The cosmic-ray contribution to the dose received by the inhabitants was also estimated. Gamma-ray spectroscopy was performed for radionuclide analyses. In situ measurements were carried out using a survey meter coupled to a sodium iodide detector. Cellulose nitrate films, ZnS (Ag) scintillation cells, and alpha spectroscopy were used to study radon and radon daughters. Radiation doses due to all natural sources were calculated and compared with that incurred in common concrete dwellings at lower altitudes.


Subject(s)
Air Pollution, Indoor , Background Radiation , Housing , Construction Materials , Cosmic Radiation , Radioisotopes/analysis , Radon/analysis , Taiwan
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