Nonthermal atmospheric pressure plasma has attracted great interest for biomedical applications. The plasma consists of charged particles, radicals, and a strong electric field as the fourth state of matter. This study evaluated the change in the surface roughness after tooth bleaching by plasma in combination with a low concentration (15%) of carbamide peroxide, specifically whether the application of plasma produced detriments, such as demineralization and structural change, with the goal of efficient and safe tooth bleaching. After being combined with plasma and 15% carbamide peroxide, the hydroxyapatite surface was significantly smoother with a low roughness average value. Tooth bleaching with 15% carbamide peroxide alone produced an irregular surface and increased the surface roughness with high roughness average value. Tooth bleaching with plasma resulted in no significant variations in hydroxyapatite in terms of change in surface roughness and surface topography. The application of tooth bleaching with plasma is not deleterious to dental hard tissue, implicating it as a safe tooth bleaching technique.
Atmospheric Pressure* ; Durapatite* ; Plasma* ; Streptococcus mutans ; Tooth Bleaching* ; Urea

Aerospace neurology concentrate on the function of nervous system exposed to environmental conditions other than those encountered in our normal standard conditions. Clinical factors in these environments include the toxic effects of changes in atmospheric pressure and considerations of safety for pilot with neurologic disease. This article gives a brief overview of the environmental factors experienced in aviation and space environments that are most associated in neurologic dysfunction.
Atmospheric Pressure ; Aviation ; Nervous System ; Neurologic Manifestations ; Neurology

Cerebral arterial air embolism (CAAE), although infrequent, is a complication that can occur at any time during an invasive medical procedure. We experienced two cases of CAAE during cerebral angiography accidentally. The author reports the two cases of CAAE wherein air emboli dissolved spontaneously and immediately under normal atmospheric pressure, not under therapeutic hyperbaric environment. One of the cases shows entire dissolution of the air embolus on the moving image. This report shows that arterial air embolus can be absorbed spontaneously, and air embolus size is one of the factors that influence air embolus dissolution besides hyperbaric oxygen condition.
Absorption* ; Atmospheric Pressure ; Cerebral Angiography ; Embolism* ; Embolism, Air ; Oxygen

Present study deals with the straight impact of hypobaric hypoxia on the quantity and composition of some predominant fecal microflora and its functional aspects. For that, isolated fecal contents of rat were exposed to two different simulated air pressures (70 kPa and 40 kPa) for different time durations (1, 3, and 5 h) and the bacterial community composition was compared with normobaric groups (101.3 kPa). It was found that the total anaerobes, Escherichia coli, Enterbacters spp., Bifidobacterium spp., Clostridium spp. were increased whereas total aerobes were decreased at both hypobaric treatments. The increased number of amplicon was detected in the pressure-treated groups than the control that clearly mentioned the disruption of microbiota structure at different simulated hypobaric-hypoxia. The amylase, protease, tannase, β-glucuronidase, and alkaline phosphatase activities were increased at these atmospheric pressures. Thus, the present investigation demonstrates that the hypobaric hypoxia is an important environmental factor which can strongly modulate the composition of intestinal flora as well as microflora-derived functional aspects.
Animals ; Atmospheric Pressure ; Bacteria, Aerobic ; Feces ; Hypoxia ; Microbiota ; Rats

BACKGROUND: Spontaneous pneumothorax is a common respiratory condition and has been postulated that it develops because of rupture of subpleural blebs. Although the morphology and ultrastructure of causative lesions are well known, the reason for rupture of sbupleural blebs is not absolutely clear. Broad consensus concerning the role of meteorological factors in spontaneous pneumothorax dose not exist. The aim of the study was to examine the influence of change of atmospheric pressure and temperature on the occurrence of spontaneous pneumothorax. MATERIAL AND METHOD: One hundred twenty eight consecutive spontaneous pnemothorax events that occurred between January 2003 and December 2004 were selected. Changes of meteorological factors of particular days from the day before for 5 consecutive days were calculated and compared between the days with pneumothorax occurrence (SP days) and the days without pneumothorax occurrence (Non SP days). The correation between change of pressure and temperature and the occurrence of SP was evaluated. RESULT: SP occurred on 117 days (16.0%) in the 2-year period. Although there was no significant differences in change of pressure factors prior 4 days of SP occurrence compare to the 4 days prior Non SP day, change of mean pressure was higher (+0.934 vs. -0.191hPa, RR 1.042, CI 1.003~1.082, p=0.033), and change of maximum pressure fall was lower (3.280 vs. 4.791 hPa, RR 1.051, CI 1.013~1.090, p=0.009) on the 4 days prior SP day. There were significant differences in change of temperature factors prior 2 days and the day of SP, Changes of mean temperature (-0.576 vs.+0.099 degrees C, RR 0.886, 95% CI 0.817~0.962, p=0.004) and maximum temperature rise (7.231 vs. 8.079 degrees C, RR 0.943 CI 0.896~0.993, p=0.027) were lower on the 2 days prior SP. But changes of mean temperature (0.533 vs. -0.103 degrees C, RR 1.141, CI 1.038~1.255, p=0.006) and maximum temperature rise (9.209 vs. 7.754 degrees C, RR 1.123, CI 1.061~1.190, p=0.000) were higher on the SP days. CONCLUSION: Change of atmospheric pressure and temperature seems to influence the chance of occurrence of SP. Meteorological phenomena that pressure rise 4 day prior to SP and following temperature fall and rise might explain the occurrence of SP. Further studies should be continued in the future.
Atmospheric Pressure* ; Blister ; Consensus ; Meteorological Concepts ; Pneumothorax* ; Rupture

PURPOSE: This study evaluated the effect of polishing techniques on surface roughness of polymethyl methacrylate (PMMA), as well as the influence of light-cured surface glaze and subsequent brushing on surface roughness. MATERIALS AND METHODS: A total of 60 PMMA specimens (10x10x5 mm) were made and then divided into 6 groups of 10 each according to the polymerization methods (under pressure or atmosphere) and the surface polishing methods (mechanical or chemical polishing) including 2 control groups. The mechanical polishing was performed with the carbide denture bur, rubber points and then pumice and lathe wheel. The chemical polishing was performed by applying a light-cured surface glaze (Plaquit(R); Dreve-Dentamid GmbH). Accura 2000(R), a non-contact, non-destructive, optical 3-dimensional surface analysis system, was used to measure the surface roughness (Ra) and 3-dimensional images were acquired. The surface roughness was again measured after ultrasonic tooth brushing in order to evaluate the influence of brushing on the surface roughness. The statistical analysis was performed with Mann-Whitney test and t-test using a 95% level of confidence. RESULTS: The chemically polished group showed a statistically lower mean surface roughness in comparison to the mechanically polished group (P = .0045) and the specimens polymerized under the atmospheric pressure presented a more significant difference (P = .0138). After brushing, all of the groups, except the mechanically polished group, presented rougher surfaces and showed no statistically significant differences between groups. CONCLUSION: Although the surface roughness increased after brushing, the chemical polishing technique presented an improved surface condition in comparison to the mechanical polishing technique.
Atmospheric Pressure ; Dentures ; Polymerization ; Polymers ; Polymethyl Methacrylate ; Rubber ; Silicates ; Tooth ; Ultrasonics

This study was undertaken to achieve a high bleaching efficacy with plasma, through longer application and reparative bleaching processes, by different shade evaluation methods. Extracted human teeth were divided into 6 groups (n=10). All teeth were treated in pairs. Low concentration of 15% carbamide peroxide (CP) was applied, with and without plasma, for 10, 20, and 30-min tooth bleaching, respectively. The bleaching procedure was repeated once daily for four days. The teeth were maintained in a moist environment provided by artificial saliva. The Vitapan Classical shade guide and Commission Internationale de L'Eclairage (CIELAB) color system were collectively used to measure the bleaching efficacy. Color evaluation was statistically analyzed using Student t-test and one-way analysis of variance (ANOVA) complemented by Tukey's test. Combining the plasma with 15% CP showed significantly greater color changes compared to bleaching without plasma (p<0.05). A high bleaching efficacy with plasma is proportional to the repetitive application and the treatment time. A 30-min application with plasma provided the best bleaching. Repetitive bleaching showed lower probability of color relapse of the bleached tooth. The color change by shade guide correlated with the changes in CIELAB color system. A value of 1 color change units (CCU) conversion factor for overall color change (ΔE) values comparisons was 3.724 values. The two measuring methods provide a more accurate correspondence of color change. The repetitive and longer application for tooth bleaching, combined with plasma, has a strong bleaching effect and produces whiter teeth.
Atmospheric Pressure* ; Complement System Proteins ; Humans ; Plasma* ; Recurrence ; Saliva, Artificial ; Tooth Bleaching* ; Tooth* ; Urea

OBJECTIVE: The aim of this study was to investigate the correlation between meteorological factors and occurrence of spontaneous intracerebral hemorrhage (ICH) according to age. MATERIALS AND METHODS: We retrospectively analyzed the records of 735 ICH patients in a metropolitan hospital-based population. Observed and expected numbers of ICH patients were obtained at 5degrees C intervals of ambient temperature and a ratio of observed to expected frequency was then calculated. Changes in ambient temperature from the day before ICH onset day were observed. The Wilcoxon-Mann-Whitney test was used to test differences in meteorological variables between the onset and non-onset days. The Kruskal-Wallis test was used for comparison of meteorological variables across gender and age. RESULTS: ICH was observed more frequently (observed/expected ratio > or = 1) at lower mean, minimum, and maximum ambient temperature (p = 0.0002, 0.0003, and 0.0002, respectively). Significantly lower mean, minimum, and maximum ambient temperature, dew point temperature, wind speed, and atmospheric pressure (p = 0.0003, 0.0005, 0.0001, 0.0013, 0.0431, and 0.0453, respectively) was observed for days on which spontaneous ICH occurred. In the subgroup analysis, the ICH onset day showed significantly lower mean, minimum, and maximum ambient temperature, dew point temperature, relative humidity, and higher atmospheric pressure in the older (> or = 65 years) female group (p = 0.0093, 0.0077, 0.0165, 0.0028, 0.0055, and 0.0205, respectively). CONCLUSION: Occurrence of spontaneous ICH is closely associated with meteorological factors and older females are more susceptible to lower ambient temperature.
Atmospheric Pressure ; Cerebral Hemorrhage* ; Female ; Humans ; Humidity ; Meteorological Concepts* ; Meteorology ; Retrospective Studies ; Wind

BACKGROUND: Although hyperbaric oxygen (HBO) -100% oxygen at two to three times the atmospheric pressure at sea level-has a number of beneficial biochemical, cellular, and physiologic effects, it is intrinsically associated with the potential for producing mild to severe toxic effects. The contribution of the cellular adhesion molecules and macrophages in the renal oxygen toxicity is not well understood. Thus, we have investigated the toxic effect of HBO expressed by the analysis of intercellular adhesion molecule-1 (ICAM-1) and infiltration of macrophages in rat kidney. METHODS: Male Sprague-Dawley rats weighing about 250 g were exposed to HBO at 3 ATA of 100% O2 for 4 hours. The expression of ICAM-1 and infiltration of CD68-positive macrophages were serially observed by immunohistochemical analysis. RESULTS: At 3 days after HBO exposure, CD68-positive macrophage counts were increased in glomeruli and tubulointerstitium of kidney. The expression of ICAM-1 was enhanced 1 day after HBO exposure and increased more for 3 days. There was a significant correlation between ICAM-1 expression and macrophage accumulation in the glomeruli. At 7 days after HBO, those alterations recovered to normal status. CONCLUSION: The 4-hour HBO exposure induced ICAM-1 expression and macrophage accumulation in the kidney and these change lasted for 3 days. Therefore, sustained activation of macrophages in renal oxygen toxicity may occur after prolonged (more than 4 hours) or repetitive exposures to HBO.
Animals ; Atmospheric Pressure ; Humans ; Intercellular Adhesion Molecule-1* ; Kidney* ; Macrophages ; Male ; Oxygen* ; Rats* ; Rats, Sprague-Dawley

PURPOSE: This study examined the influence of meteorological phenomena on the development of spontaneous pneumothorax (SP). METHODS: We conducted this study from January to November 2004. We obtained the daily SP incidence from data requested by the National Health Insurance office from general hospital in Daejon, and we got the meteorological data from the Daejon Regional Meteorologic office. The difference in meteorological phenomena between cluster days (3 or more SP) and no SP days was analyzed using a generalized additive model (GAM) that used a specialized form of the non-parametric, non-linear regression test. RESULTS: Five hundred sixty-six SP patients were included. There were 369 male patients and 74 female patients. SP patients were associated with significantly lower atmospheric pressure and with broad swings of daily atmospheric pressure for 4-7 days prior to the hospital visits. More clouds had gathered for several days before cluster days than had gathered on days with no SP. CONCLUSION: Development of SP is related with meteorological phenomena. SP occurs when lower atmospheric pressure, broad swings of atmospheric pressure, and cloudy weather are collectively exprienced for several days before the hospital visit.
Atmospheric Pressure ; Daejeon ; Female ; Hospitals, General ; Humans ; Incidence ; Male ; Meteorological Concepts ; National Health Programs ; Pneumothorax* ; Weather