Types Of Protectors Research Articles

Reconstruction of the choana in a teenager with congenital unilateral choanal atresia after multiple choanal surgery. Case report

Choanal atresia (CA) is a congenital pathology, the frequency of which currently stands at 1 in 8000 newborns. The cause of congenital choanal atresia has not been definitively established at the moment. Diagnosis of CA often is made by pediatricians or neonatologists in the ICU oh the maternity hospital. In case of bilateral CA diagnosis is often not difficult and the diagnosis is often suggested right after labor due to asphyxia, but with a unilateral process, children can live for years without nasal obstruction in case of compensated nasal breathing. Today approaches to CA repair in children remain controversial. And if, in a bilateral process, surgical intervention is recommended to be done as early as possible, in case of the correction of the unilateral process may be postponed until older age. There is also no clear opinion on the approaches to surgical approaches, the use of protectors, the duration of their installation and the type of protector used is also controversial. The article describes a clinical case of adolescent with bilateral CA with multiple choanoplasty surgeries and restenosis. The child was admitted to Otorhinolaryngology Department of the Veltischev Research and Clinical Institute of Pediatrics and Children surgery. Despite the diagnosis that was made on time, the patient managed to improve nasal breathing only by the age of 15 after choanal reconstruction.

Measuring the effects of respiratory protective equipment and other protectors in preventing the scattering of vocalization droplets.

This study was conducted to quantitatively examine the effects of respiratory protective equipment (respirators) and various other types of protectors in preventing the scattering of vocalization droplets. Each of 12 adult male volunteers was asked to vocalize intermittently for 1 min at a target intensity of approximately 100 dBA in an experimental room adjusted to a humidity of approximately 60-70%. The subjects vocalized while wearing respirators, other types of protectors, or no protectors at all. The droplet concentration in a particle size range of 0.3 to 10 μm was measured under each experimental condition, and the transmitted particle concentration and penetration were calculated. The concentration and penetration of particles transmitted from the respirators were lower than those transmitted from the other protectors examined. The probability of infection reduction through the use of the protectors was estimated from the data obtained on the effectiveness of the protectors in preventing the scattering of droplets. We concluded that there is no need for additional droplet scattering prevention in various work settings when appropriate respirators are used under optimal conditions.

Personal attenuation ratings versus derated noise reduction ratings for hearing protection devices.

National and international regulatory and consensus standards setting bodies have previously proposed derating hearing protector ratings to provide a better match between ratings determined in a laboratory and the real-world measurements of attenuation for workers. The National Institute for Occupational Safety and Health has proposed a derating scheme that depends upon the type of protector. This paper examines four real-world studies where personal attenuation ratings (PARs) were measured at least twice, before and after an intervention in earplug fitting techniques. Results from these studies indicate that individualized earplug fitting training dramatically improves a worker's achieved PAR value. Additionally, derating schemes fail to accurately predict the majority of achieved PARs. Because hearing protector fit testing systems are now readily available for use in the workplace, personal attenuation ratings provide a better estimate of worker noise exposures and are able to identify those persons who need additional instruction in fitting hearing protection devices.

Evaluation of dental enamel color after fixed orthodontic therapy using two types of protectors to prevent white spot lesions (A prospective clinical study)

Background: The aim of this study is to evaluate the color change ∆E of the dental enamel following treatment with 2 kinds of protector (icon infiltrant, clinpro varnish) before fixed orthodontic treatment to avoid the possible white spot lesions. Materials and Methods: Fifty four subjects treated with fixed appliances were divided into 3 groups: the 1st group was control, while the 2nd and 3rd groups were treated with icon infiltrant and clinpro varnish before bonding procedure, respectively. Color parameters (L,a,b) were recorded for the middle and gingival thirds before and after bonding procedure to get the ∆E of each group. Results: One-way ANOVA test showed a non-significant difference in ∆E between the 3 groups at p value <0.05, while there were highly significant differences in value of ∆E between middle thirds and the gingival thirds in all groups. Conclusion: The icon infiltrant and clinpro varnish have no effect on color of the enamel when used before the bonding procedure. Color change ∆E occurring in middle third is higher than that of the gingival third. Keywords: Color change, protector, white spot lesions

Attenuation of high-level acoustic impulses by hearing protectors

Attenuation of acoustic impulses by hearing protectors was measured in peak level ranges of 115–135 dB and 145–170 dB. The impulses were generated by a loudspeaker system in the low range of levels and by a blast of air expanding from a cylinder in the high level range. Transmission loss method was used to determine the difference between the peak level under the earmuff and outside the earmuff for over 30 different types of earmuffs. The measurements confirm that attenuation of high-level impulses depends on their peak level. In the 115–135 dB range the difference between the peak level outside and under the earmuff is approximately constant. In the 145–170 dB range, as the impulse level is increased, the level under the earmuff increases to a lesser extent. The peak-to-peak level characteristics determined for the 115 to 170 dB level range substantially differ for various types of protectors and may be a useful indicator of the effectiveness of protectors for impulse noise. [Work supported by the State Committee for Scientific Research Grants Nos. <cn>III-7.03<cnx> and <cn>III-6.07<cnx>.]

Speech perception in noise when wearing hearing protectors with little low-frequency attenuation

In industrial workplaces, it is widely believed that the use of hearing protectors interferes with communication and with the perception of warming signals. The objective of this study was to estimate effects of attenuation of the protectors on speech perception in noise. In the experiment, the intelligibility of monosyllables was assessed for ten normal-hearing adults, using three types of protectors with different attenuation characteristics. The speech materials were presented at two speech levels (65 and 85 dBA) in noise. The noise level was altered at signal-to-noise ratios (SNR) of 0, +5, and +10 dB. The results showed that speech intelligibility was significantly influenced by type of protector, speech level, and SNR. The interaction between these factors was statistically significant. The wearing of the earplug with decreased low-frequency attenuation resulted in less deterioration when the speech was presented at 65 dBA. On the other hand, such an earplug did not improve speech intelligibly as compared with other protectors when the speech was presented at 85 dBA. Therefore, the use of the protectors with decreased attenuation to improve speech communication for workers wearing protectors needs to be re-examined.

Mouth protectors and sports team dentists

A mouth protector must be easy to fabricate, comfortable, able to accommodate the needs of an individual's dentition, durable, easily held in place, and able to provide adequate protection to the teeth, jaws, and cranial structures. The thermoplastic mouth protector is recommended if it is to be placed or formed by the athlete; however, supervision of the fitting procedure by a dentist is recommended. The most desirable protector, however, is the custom-made mouth protector fabricated by a dentist from a thermoplastic material. With the custom-made protector, the dentist can optimize fit, comfort, and speech as well as tend to any control of form to the special dental requirements of the athlete. Thousands of football players have avoided oral injuries by wearing mouth protectors and faceguards. In other sports, dental safety still needs to be improved. National athletic organizations should be urged to require players to wear adequate mouth protectors. Dentists, health and physical education professionals, and other concerned persons should tell all athletes, patients, and parents, why mouth protectors are necessary and what types of protectors effectively reduce or minimize the incidence of injury. All organized sports teams should have their own team dentists to help ensure that players maintain the best possible oral health. If these actions are taken, fewer athletes will suffer the pain, inconvenience, and expense of unnecessary and frequently disfiguring oral injuries.

Radiolytic reduction of ceric ions in water DMSO mixtures and radioprotection

It is convenient to classify mechanisms of radioproteetion into those that involve fast radiation chemical processes and those in which the protection is the result of changes in the cell biochemistry. In the former, the added protectors have two principal effects: OH scavenging which reduces the radiosensitised damage and fast chemical repair processes involving hydrogen donation from the protector to the target radical. Typical of the first type of protector is dimethyl sulphoxide(DMSO)1 because it is known to be a good OH scavenger (kOH+DMSO =5×109 mol−1 s−1. (ref. 2). We have attempted to establish the redox properties of the OH radical adduct3 as well as those of H2O2 or H and HO2 radicals in water–DMSO mixtures. To this end we added to the solutions containing 0.5 M H2SO4, cerie ions at concentrations varying from 2.5 × 10−3 to 5 × 10−2 M. The Ce4+ reduction yield was determined as a function of the DMSO content in the solution, by irradiating the mixture with γ rays, in the presence or absence of air. The details of the experimental procedure will be given elsewhere. We report here that the yields (G) are independent of the Ce4+ concentration in the range studied and of the presence or absence of air, and depend only on the DMSO concentration.

High-Frequency Attenuation Characteristics of Ear Protectors

The attenuation of ear protectors was examined at 8, 10, 12, 14, 16, and 18 kHz. Four different varieties of protection devices were used. These included three types of plugs—foam, rubber, and custom fitted—and a muff. Ten young normal-hearing listeners were tested (on three different days) by means of a Békésy tracking procedure. The stimulus was a pulsed 300-Hz band of noise centered around the test frequency. The results revealed a wide range of attenuation provided by the four types of protectors. The most protection was afforded by the foam plug, followed by the rubber plug and muff. The custom mold provided the least amount of attenuation. For each protector the attenuation was relatively constant between 8 to 16 kHz, with the greatest protection offered at 14 kHz.

The Use of Hypodermic Needles as Critical Orifices in Air Sampling

Hypodermic needles are useful as convenient low-cost critical orifices to control the flow rate in air sampling. Variations in flow rate were less than five per cent for 41 needle gauge-length combinations. To provide maximum accuracy, a simple calibration procedure is described. Needles may be reused more than six times, if protected. Types of protectors are described. Resistances of protector, collector, and prefilter combinations affect criticality at nine liters/min. Simple sampling devices using needles as orifices are described.

Variation in Ear Protector Attenuation as Measured by Different Methods

The ASA standard “Method for the measurement of the real-ear attenuation of ear protectors at threshold”—Z24.22/406, specifies the use of threshold shift techniques. It has been observed in our laboratory during extensive evaluation of developmental ear protective devices over the past ten years that large differences in attenuation are obtained when using different attenuation measuring techniques. In addition, these differences vary for the different types of protectors being studied. In the study reported herein, four grossly different types of protectors were measured. These protectors differ in the volume under the protector and in the principal sound transmission path at low frequencies. The test subjects and room environment were the same for all the measurements. The results indicate that threshold shift measurements yield higher values of attenuation than either loudness balance or the microphone method. However, the results vary widely for different types of protectors as a function of frequency. Differences of 3 db or greater between protector types as measured by any of the three measuring techniques were found to be significant at the 95% confidence level using four subjects and three replications.

How Much Ear Protection?

The proposed ASA Standard “Method for the Measurement of The Real-Ear Attenuation of Ear Protectors at Threshold”—Z24.22/406, which is currently being considered for adoption, specifies the use of threshold shift techniques. It has been observed in our laboratory during extensive evaluation of developmental ear protective devices over the past ten years that large differences in attenuation are obtained when using different attenuation measuring techniques. In addition, these differences vary for the different type of protector being studied. In this study four grossly different types of protectors are measured. These protectors differ in volume under the protector and in the principal sound transmission path at low frequencies. The protective devices included (1) HS-33 headset using the MX-41 muff, (2) H-70C/AIC headset using the MX-2088 muff, (3) RCA “Quiet-Ear” protector, and (4) RCA experimental ear protector. The attenuation methods employed are (1) threshold shift using a Békésy type audiometer, (2) loudness balance at approximately 60-phon level, and (3) objective method using a miniature microphone. The test subjects and room environment are the same for all types of measurements. A discussion of the differences in attenuation values obtained from the three methods will be given. [Supported in part by the U. S. Air Force under Contract AF 33 (600)-33172.]