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30 بهمن 87 - 17:18تاثیر اتر بر مکانیسم بدن چگونه است اطلاعات بیشتر : همینتاریخ ایجاد سوال : 30 بهمن 87 (17:18)تاریخ بسته شدن سوال : 16 اسفند 87تعداد بازدید :139تعداد پاسخ ها : 3طبقه بندی : سلامتی » دارو- این سوال منقضی شده است. و بهترین جواب توسط رای کاربران انتخاب شده است.

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87/11/30 (18:29)INTRODUCTION

This guideline summarizes pertinent information about ethyl ether for workers and employers as well as for physicians, industrial hygienists, and other occupational safety and health professionals who may need such information to conduct effective occupational safety and health programs. Recommendations may be superseded by new developments in these fields; readers are therefore advised to regard these recommendations as general guidelines and to determine whether new information is available.

SUBSTANCE IDENTIFICATION

* Formula

C(4)H(10)O
* Structure

(For Structure, see paper copy)
* Synonyms

Diethyl ether; 1,1'-oxybisethane; ethyl oxide; anesthetic ether;
diethyl oxide; sulfuric ether; ethoxyethane
* Identifiers

1. CAS No.: 60-29-7

2. RTECS No.: KI5775000

3. DOT UN: 1155 26

4. DOT label: Flammable Liquid

* Appearance and odor

Ethyl ether is a clear, colorless liquid with a characteristic, sweet ether odor. The air odor threshold concentration for ethyl ether is 8.9 parts per million (ppm) parts of air.
CHEMICAL AND PHYSICAL PROPERTIES

* Physical data

1. Molecular weight: 74.1

2. Boiling point (at 760 mm Hg): 34.5 degrees C (94.1 degrees F)

3. Specific gravity (water = 1): 0.71 at 20 degrees C (68 degrees F)

4. Vapor density: 2.55

5. Freezing point: -116.3 degrees C (-177.3 degrees F)

6. Vapor pressure at 20 degrees C (68 degrees F): 442 mm Hg

7. Solubility: Slightly soluble in water; soluble in alcohol, acetone, benzene, and chloroform.

8. Evaporation rate: Data not available.

* Reactivity

1. Conditions contributing to instability: Heat, sparks, flame light, shock. Ethers that have been in contact with air or exposed to light for a long time may contain peroxides; ethers that contain peroxides may explode when the caps or stoppers of their containers are removed. Because ethyl ether is a nonconductor, static electric charges may accumulate and cause ignition of its vapors.

2. Incompatibilities: Contact between ethyl ether and strong oxidizing agents, halogens, interhalogens, sulfur and sulfur compounds should be avoided.

3. Hazardous decomposition products: Toxic gases and vapors (such as carbon monoxide) may be released in a fire involving ethyl ether.

4. Special precautions: None reported.

* Flammability

The National Fire Protection Association has assigned a flammability rating of 4 (extreme fire hazard) to ethyl ether.
1. Flash point: -45 degrees C (-49 degrees F) (closed cup)

2. Autoignition temperature: 180 degrees C (356 degrees F)

3. Flammable limits in air (percent by volume): Lower, 1.9; upper, 36.0

4. Extinguishant: For small fires use dry chemical, carbon dioxide, water spray, or alcohol-resistant foam. Use water spray, fog, or alcohol-resistant foam to fight large fires involving ethyl ether DOT 1993, Guide 26].

Fires involving ethyl ether should be fought upwind from the maximum distance possible. Keep unnecessary people away; isolate the hazard area and deny entry. Isolate the area for 1/2 mile in all directions if a tank, rail car, or tank truck is involved in the fire. For a massive fire in a cargo area, use unmanned hose holders or monitor nozzles; if this is impossible, withdraw from the area and let the fire burn. Emergency personnel should stay out of low areas. Vapors may travel to a source of ignition and flash back. Vapors are an explosion and poison hazard indoors, outdoors, or in sewers. Containers of ethyl ether may explode in the heat of the fire and should be moved from the fire area if it is possible to do so safely. If this is not possible, cool fire exposed containers from the sides with water until well after the fire is out. Stay away from the ends of containers. Personnel should withdraw immediately if a rising sound from a venting safety device is heard or if there is discoloration of a container due to fire. Firefighters should wear a full set of protective clothing and self-contained breathing apparatus when fighting fires involving ethyl ether.
EXPOSURE LIMITS

* OSHA PEL

The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for ethyl ether is 400 ppm (1200 milligrams per cubic meter (mg/m(3))) as an 8-hour time-weighted average (TWA) concentration [29 CFR 1910.1000, Table Z-1].
* NIOSH REL

* The National Institute for Occupational Safety and Health has not established a recommended exposure limit for ethyl ether.

* ACGIH TLV

The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned ethyl ether a threshold limit value (TLV) of 400 ppm (1210 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek and a short-term exposure limit (STEL) of 500 ppm (1520 mg/m(3)) for periods not to exceed 15 minutes. Exposures at the STEL concentration should not be repeated more than four times a day and should be separated by intervals of at least 60 minutes [ACGIH 1994, p. 21].
* Rationale for Limits

The ACGIH limits are based on the risk of narcosis and irritation [ACGIH 1991, p. 631].
HEALTH HAZARD INFORMATION

* Routes of Exposure

Exposure to ethyl ether can occur through inhalation, ingestion, and eye or skin contact [Sittig 1991].
* Summary of toxicology

1. Effects on Animals: Ethyl ether is a severe irritant of the eyes and mucous membrane; at high concentrations, ethyl ether causes central nervous system depression. The oral LD(50) in rats is 1,215 mg/kg, and the LC(50) in rats is 73,000 ppm for 2 hours [NIOSH 1991]. The lethal concentration for a single exposure in monkeys is reportedly between 71,600 ppm and 192,500 ppm ethyl ether by volume. Exposure to a 6.4 percent concentration caused deep anesthesia in mice, and respiratory arrest occurred at 128,000 ppm ethyl ether. Rats exposed chronically over 30 weeks to 2,000 ppm ethyl ether did not experience adverse effects in the blood or kidneys and body weight changes. However, the blood levels of liver enzymes were elevated, although microscopic examination failed to identify any liver damage. A decrease in the weight of the liver relative to body weight was noted [Clayton and Clayton 1982]. Contact of the eyes of rabbits with the liquid or the vapor may produce slight, reversible corneal injury [Grant 1986]. Ethyl ether is mutagenic in bacterial and mammalian test systems [NIOSH 1991].

2. Effects on Humans: Ethyl ether has been used to produce surgical anesthesia in humans; the concentration that is needed to induce anesthesia in humans ranges from 100,000 to 150,000 ppm. After anesthesia has been induced, it is maintained at about 50,000 ppm because respiratory arrest may occur at higher concentrations [Hathaway et al. 1991]. At 200 ppm, mild nasal irritation occurs, and at 2,000 ppm, dizziness may be experienced [ACGIH 1991; Hathaway et al. 1991]. Brief exposures of the eyes to the liquid or to high vapor concentrations produced burning but no injury. Prolonged exposure may cause temporary corneal epithelial injury [Grant 1986]. Prolonged skin contact can cause burns. Ethyl ether is also a defatting agent, and repeated exposure may cause skin drying and cracking [Genium 1988].

* Signs and symptoms of exposure

1. Acute exposure: Ethyl ether causes a wide range of effects depending on the concentration and length of exposure. Symptoms include irritation of the nose and eyes, dizziness, acute excitement, drowsiness, vomiting, paleness, decreased pulse rate, decreased body temperature, irregular respiration, muscle relaxation, lung irritation with increased bronchial secretions, laryngospasm, loss of consciousness, and death [Clayton and Clayton 1982]. Post-narcosis effects include excessive salivation, vomiting, headaches, and irritation of the respiratory tract [Clayton and Clayton 1982].

2. Chronic exposure: Long-term exposure of the skin to ethyl ether may cause dermatitis.

EMERGENCY MEDICAL PROCEDURES

* Emergency medical procedures: [NIOSH to supply]

5. Rescue: Remove an incapacitated worker from further exposure and implement appropriate emergency procedures (e.g., those listed on the Material Safety Data Sheet required by OSHA's Hazard Communication Standard [29 CFR 1910.1200]). All workers should be familiar with emergency procedures, the location and proper use of emergency equipment, and methods of protecting themselves during rescue operations.

EXPOSURE SOURCES AND CONTROL METHODS

The following operations may involve ethyl ether and lead to worker exposures to this substance:


* The manufacture and transportation of ethyl ether
* Used as a solvent for waxes, fats, oils, alkaloids, gums, resins, nitrocellulose, hydrocarbons, raw rubber, smokeless powder, textiles, rayon, plastic, and dyes

* Used as an anesthetic in human and animal medicine

* Liberated from manufacture of alkali or sodium ethylxanthotes by heated processes; from manufacture of warm- and cold-process pharmaceuticals; from manufacture of chemicals from cold processesþ Grignard reactions and acetic acid recovery

* Used as a refrigerant; as an extractant in diesel fuels and dry cleaning; as a chemical reagent for organic reactions

* Used as an additive in motor fuels, perfumes, and denatured alcohol

* Used as an intermediate for monoethanolamine and ethylene

* Used as an anesthetic, antispasmodic, and rubefacient in animal medicine

Methods that are effective in controlling worker exposures to ethyl ether, depending on the feasibility of implementation, are as follows:


* Process enclosure
* Local exhaust ventilation
* General dilution ventilation
* Personal protective equipment
Workers responding to a release or potential release of a hazardous substance must be protected as required by paragraph (q) of OSHA's Hazardous Waste Operations and Emergency Response Standard [29 CFR 1910.120].

Good sources of information about control methods are as follows:

1. ACGIH [1992]. Industrial ventilation--a manual of recommended practice. 21st ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

2. Burton DJ [1986]. Industrial ventilation--a self study companion. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

3. Alden JL, Kane JM [1982]. Design of industrial ventilation systems. New York, NY: Industrial Press, Inc.

4. Wadden RA, Scheff PA [1987]. Engineering design for control of workplace hazards. New York, NY: McGraw-Hill.

5. Plog BA [1988]. Fundamentals of industrial hygiene. Chicago, IL: National Safety Council.

MEDICAL SURVEILLANCE

OSHA is currently developing requirements for medical surveillance. When these requirements are promulgated, readers should refer to them for additional information and to determine whether employers whose employees are exposed to ethyl ether are required to implement medical surveillance procedures.

* Medical Screening

Workers who may be exposed to chemical hazards should be monitored in a systematic program of medical surveillance that is intended to prevent occupational injury and disease. The program should include education of employers and workers about work-related hazards, early detection of adverse health effects, and referral of workers for diagnosis and treatment. The occurrence of disease or other work-related adverse health effects should prompt immediate evaluation of primary preventive measures (e.g., industrial hygiene monitoring, engineering controls, and personal protective equipment). A medical surveillance program is intended to supplement, not replace, such measures. To detect and control work-related health effects, medical evaluations should be performed (1) before job placement, (2) periodically during the term of employment, and (3) at the time of job transfer or termination.
* Preplacement medical evaluation

Before a worker is placed in a job with a potential for exposure to ethyl ether, a licensed health care professional should evaluate and document the worker's baseline health status with thorough medical, environmental, and occupational histories, a physical examination, and physiologic and laboratory tests appropriate for the anticipated occupational risks. These should concentrate on the function and integrity of the skin, liver, kidneys, and respiratory system. Medical surveillance for respiratory disease should be conducted using the principles and methods recommended by the American Thoracic Society.
A preplacement medical evaluation is recommended to assess medical conditions that may be aggravated or may result in increased risk when a worker is exposed to ethyl ether at or below the prescribed exposure limit. The health care professional should consider the probable frequency, intensity, and duration of exposure as well as the nature and degree of any applicable medical condition. Such conditions (which should not be regarded as absolute contraindications to job placement) include a history and other findings consistent with diseases of the skin, liver, kidneys, or respiratory system.
* Periodic medical evaluations

Occupational health interviews and physical examinations should be performed at regular intervals during the employment period, as mandated by any applicable Federal, State, or local standard. Where no standard exists and the hazard is minimal, evaluations should be conducted every 3 to 5 years or as frequently as recommended by an experienced occupational health physician. Additional examinations may be necessary if a worker develops symptoms attributable to ethyl ether exposure. The interviews, examinations, and medical screening tests should focus on identifying the adverse effects of ethyl ether on the skin, liver, kidneys, or respiratory system. Current health status should be compared with the baseline health status of the individual worker or with expected values for a suitable reference population.
* Termination medical evaluations

The medical, environmental, and occupational history interviews, the physical examination, and selected physiologic or laboratory tests that were conducted at the time of placement should be repeated at the time of job transfer or termination to determine the worker's medical status at the end of his or her employment. Any changes in the worker's health status should be compared with those expected for a suitable reference population.
* Biological monitoring

Biological monitoring involves sampling and analyzing body tissues or fluids to provide an index of exposure to a toxic substance or metabolite. A readily available biological monitoring method for ethyl ether involves the measurement of ether concentrations in the blood by means of gas chromatography. Blood ether concentrations have been found to correlate with both the degree of worker exposure and the extent of intoxication; blood ether concentrations should not exceed a level of about 20 mg/L in asymptomatic workers.
WORKPLACE MONITORING AND MEASUREMENT

Determination of a worker's exposure to airborne ethyl ether is made using a charcoal tube (100/50 mg sections, 20/40 mesh). Samples are collected at a maximum flow rate of 0.2 liter/minute (STEL or TWA) until a maximum collection volume of 3 liters (STEL or TWA) is reached. The sample is then treated with ethyl acetate. Analysis is conducted by gas chromatography using a flame ionization detector (GC/FID). This method is fully validated and is described in the OSHA Computerized Information System [OSHA 1994] and in NIOSH Method No. 1610 [NIOSH 1994b].

PERSONAL HYGIENE PROCEDURES

If ethyl ether contacts the skin, workers should immediately wash the affected areas with soap and water.

Clothing contaminated with ethyl ether should be removed immediately, and provisions should be made for the safe removal of the chemical from the clothing. Persons laundering the clothes should be informed of the hazardous properties of ethyl ether, particularly its potential for causing narcosis.

A worker who handles ethyl ether should thoroughly wash hands, forearms, and face with soap and water before eating, using tobacco products, using toilet facilities, applying cosmetics, or taking medication.

Workers should not eat, drink, use tobacco products, apply cosmetics, or take medication in areas where ethyl ether or a solution containing ethyl ether is handled, processed, or stored.

STORAGE

Ethyl ether should be stored in a cool, dry, well-ventilated area in tightly sealed containers that are labeled in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200]. Detached outside storage is preferred; if containers are stored inside, a standard flammable liquids storage room or cabinet should be used. Containers of ethyl ether should be protected from physical damage, direct sunlight, ignition sources, and should be stored separately from strong oxidizing agents, halogens, interhalogens, sulfur and sulfur compounds.

SPILLS AND LEAKS

In the event of a spill or leak involving ethyl ether, persons not wearing protective equipment and clothing should be restricted from contaminated areas until cleanup has been completed. The following steps should be undertaken following a spill or leak:

1. Notify safety personnel.

2. Remove all sources of heat and ignition.

3. Ventilate potentially explosive atmospheres.

4. Do not touch the spilled material; stop the leak if it is possible to do so without risk.

5. Use non-sparking tools.

6. Water spray may be used to reduce vapors, but the spray may not prevent ignition in closed spaces.

7. For small liquid spills, take up with sand or other noncombustible absorbent material and place into closed containers for later disposal.

8. For large liquid spills, build dikes far ahead of the spill to contain the ethyl ether for later reclamation or disposal.

SPECIAL REQUIREMENTS

U.S. Environmental Protection Agency (EPA) requirements for emergency planning, reportable quantities of hazardous releases, community right-to-know, and hazardous waste management may change over time. Users are therefore advised to determine periodically whether new information is available.

* Emergency planning requirements

Ethyl ether is not subject to EPA emergency planning requirements under the Superfund Amendments and Reauthorization Act (SARA) (Title III) in 42 USC 11022.
* Reportable quantity requirements for hazardous releases

A hazardous substance release is defined by EPA as any spilling, leaking, pumping, pouring, emitting, emptying, discharging, injecting, escaping, leaching, dumping, or disposing into the environment (including the abandonment or discarding of contaminated containers) of hazardous substances. In the event of a release that is above the reportable quantity for that chemical, employers are required to notify the proper Federal, State, and local authorities [40 CFR 355.40].
The reportable quantity of ethyl ether is 100 pounds. If an amount equal to or greater than this quantity is released within a 24-hour period in a manner that will expose persons outside the facility, employers are required to do the following:
- Notify the National Response Center immediately at (800) 424-8802 or at (202) 426-2675 in Washington, D.C. [40 CFR 302.6].
* Community right-to-know requirements

Employers are not required by EPA in 40 CFR Part 372.30 to submit a Toxic Chemical Release Inventory form (Form R) to EPA reporting the amount of ethyl ether emitted or released from their facility annually.
* Hazardous waste management requirements

EPA considers a waste to be hazardous if it exhibits any of the following characteristics: ignitability, corrosivity, reactivity, or toxicity as defined in 40 CFR 261.21-261.24. Under the Resource Conservation and Recovery Act (RCRA) [40 USC 6901 et seq.], EPA has specifically listed many chemical wastes as hazardous. Ethyl ether is listed as a hazardous waste under RCRA and has been assigned EPA Hazardous Waste No. U117. It is approved for land disposal after treatment and only if the concentration of ethyl ether in the waste or treatment residual does not exceed 160 mg/kg.
Providing detailed information about the removal and disposal of specific chemicals is beyond the scope of this guideline. The U.S. Department of Transportation, EPA, and State and local regulations should be followed to ensure that removal, transport, and disposal of this substance are conducted in accordance with existing regulations. To be certain that chemical waste disposal meets EPA regulatory requirements, employers should address any questions to the RCRA hotline at (703) 412-9810 (in the Washington, D.C. area) or toll-free at (800) 424-9346 (outside Washington, D.C.). In addition, relevant State and local authorities should be contacted for information on any requirements they may have for the waste removal and disposal of this substance.
RESPIRATORY PROTECTION

* Conditions for respirator use

Good industrial hygiene practice requires that engineering controls be used where feasible to reduce workplace concentrations of hazardous materials to the prescribed exposure limit. However, some situations may require the use of respirators to control exposure. Respirators must be worn if the ambient concentration of ethyl ether exceeds prescribed exposure limits. Respirators may be used (1) before engineering controls have been installed, (2) during work operations such as maintenance or repair activities that involve unknown exposures, (3) during operations that require entry into tanks or closed vessels, and (4) during emergencies. Workers should only use respirators that have been approved by NIOSH and the Mine Safety and Health Administration (MSHA).
* Respiratory protection program

Employers should institute a complete respiratory protection program that, at a minimum, complies with the requirements of OSHA's Respiratory Protection Standard [29 CFR 1910.134]. Such a program must include respirator selection, an evaluation of the worker's ability to perform the work while wearing a respirator, the regular training of personnel, respirator fit testing, periodic workplace monitoring, and regular respirator maintenance, inspection, and cleaning. The implementation of an adequate respiratory protection program (including selection of the correct respirator) requires that a knowledgeable person be in charge of the program and that the program be evaluated regularly. For additional information on the selection and use of respirators and on the medical screening of respirator users, consult the latest edition of the NIOSH Respirator Decision Logic [NIOSH 1987b] and the NIOSH Guide to Industrial Respiratory Protection [NIOSH 1987a].
PERSONAL PROTECTIVE EQUIPMENT

Workers should use appropriate personal protective clothing and equipment that must be carefully selected, used, and maintained to be effective in preventing skin contact with ethyl ether. The selection of the appropriate personal protective equipment (PPE) (e.g., gloves, sleeves, encapsulating suits) should be based on the extent of the worker's potential exposure to ethyl ether. The resistance of various materials to permeation by ethyl ether is shown below:


Material Breakthrough time (hr)


polyvinyl alcohol >8
teflon >8
4H (PE/EVAL) >8
barricade >8
responder >4
butyl rubber <1(*)
natural rubber <1(*)
neoprene <1(*)
nitrile rubber <1(*)
polyethylene <1(*)
polyvinyl chloride <1(*)
viton <1(*)
saranex <1(*)
chemrel <1(*)

(*) Not recommended, degradation may occur

To evaluate the use of these PPE materials with ethyl ether, users should consult the best available performance data and manufacturers' recommendations. Significant differences have been demonstrated in the chemical resistance of generically similar PPE materials (e.g., butyl) produced by different manufacturers. In addition, the chemical resistance of a mixture may be significantly different from that of any of its neat components.

Any chemical-resistant clothing that is used should be periodically evaluated to determine its effectiveness in preventing dermal contact. Safety showers and eye wash stations should be located close to operations that involve ethyl ether.

Splash-proof chemical safety goggles or face shields (20 to 30 cm long, minimum) should be worn during any operation in which a solvent, caustic, or other toxic substance may be splashed into the eyes.

In addition to the possible need for wearing protective outer apparel (e.g., aprons, encapsulating suits), workers should wear work uniforms, coveralls, or similar full-body coverings that are laundered each day. Employers should provide lockers or other closed areas to store work and street clothing separately. Employers should collect work clothing at the end of each work shift and provide for its laundering. Laundry personnel should be informed about the potential hazards of handling contaminated clothing and instructed about measures to minimize their health risk.

Protective clothing should be kept free of oil and grease and should be inspected and maintained regularly to preserve its effectiveness.

Protective clothing may interfere with the body's heat dissipation, especially during hot weather or during work in hot or poorly ventilated work environments.

REFERENCES

ACGIH [1991]. Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

ACGIH [1994]. 1994-1995 Threshold limit values for chemical substances and physical agents and biological exposure indices. Cincinnati, OH: American Conference of Governmental Industrial Hygienists.

Amoore JE, Hautala E [1983]. Odor as an aid to chemical safety: odor thresholds compared with threshold limit values and volatilities for 214 industrial chemicals in air and water dilution. J of App Tox 3(6):272-290.

ATS [1987]. Standardization of spirometry -- 1987 update. American Thoracic Society. Am Rev Respir Dis 136:1285-1296.

Baselt RC [1988]. Biological monitoring methods for industrial chemicals. 2nd ed. Davis, CA: Biomedical Publications.

CFR. Code of Federal regulations. Washington, DC: U.S. Government Printing Office, Office of the Federal Register.

Clayton G, Clayton F [1981-1982]. Patty's industrial hygiene and toxicology. 3rd rev. ed. New York, NY: John Wiley & Sons.

DOT [1993]. 1993 Emergency response guidebook, guide 26. Washington, DC: U.S. Department of Transportation, Office of Hazardous Materials Transportation, Research and Special Programs Administration.

Forsberg K, Mansdorf SZ [1993]. Quick selection guide to chemical protective clothing. New York, NY: Van Nostrand Reinhold.

Genium [1988]. Material safety data sheet No. 343. Schenectady, NY: Genium Publishing Corporation.

Grant WM [1986]. Toxicology of the eye. 3rd ed. Springfield, IL: Charles C Thomas.

Hathaway GJ, Proctor NH, Hughes JP, and Fischman ML [1991]. Proctor and Hughes' chemical hazards of the workplace. 3rd ed. New York, NY: Van Nostrand Reinhold.

Lewis RJ, ed. [1993]. Hawley's condensed chemical dictionary. 12th ed. New York, NY: Van Nostrand Reinhold Company.

Lide DR [1993]. CRC handbook of chemistry and physics. 73rd ed. Boca Raton, FL: CRC Press, Inc.

Mickelsen RL, Hall RC [1987]. A breakthrough time comparison of nitrile and neoprene glove materials produced by different glove manufacturers. Am Ind Hyg Assoc J 48(11): 941-947.

Mickelsen RL, Hall RC, Chern RT, Myers JR [1991]. Evaluation of a simple weight-loss method for determining the permeation of organic liquids through rubber films. Am Ind Hyg Assoc J 52(10): 445-447.

NFPA [1986]. Fire protection guide on hazardous materials. 9th ed. Quincy, MA: National Fire Protection Association.

NIOSH [1987a]. NIOSH guide to industrial respiratory protection. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-116.

NIOSH [1987b]. NIOSH respirator decision logic. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 87-108.

NIOSH [1991]. Registry of toxic effects of chemical substances: Ethyl Ether. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, Division of Standards Development and Technology Transfer, Technical Information Branch.

NIOSH [1994a]. NIOSH pocket guide to chemical hazards. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-116.

NIOSH [1994b]. NIOSH manual of analytical methods. 4th ed. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113.

NJDH [1986]. Hazardous substance fact sheet: Ethyl Ether. Trenton, NJ: New Jersey Department of Health.

NLM [1992]. Hazardous substances data bank: Ethyl Ether. Bethesda, MD: National Library of Medicine.

OSHA [1994]. Computerized information system. Washington, DC: U.S. Department of Labor, Occupational Safety and Health Administration.

Parmeggiani L [1983]. Encyclopedia of occupational health and safety. 3rd rev. ed. Geneva, Switzerland: International Labour Organisation.

Sittig M [1991]. Handbook of toxic and hazardous chemicals. 3rd ed. Park Ridge, NJ: Noyes Publications.

USC. United States code. Washington. DC: U.S. Government Printing Office.

.51%دیگر پاسخ ها
shahzade5نام : داداش مهدی امپراطورامتیاز : 100درصد بهترین پاسخ : 0% داداش مهدی امپراطور (537)i

1.    87/11/30 (23:30)Physical data

1. Molecular weight: 74.1

2. Boiling point (at 760 mm Hg): 34.5 degrees C (94.1 degrees F)

.9%
mahdanaنام : غلامرضا صفائیامتیاز : 19747درصد بهترین پاسخ : 33%غلامرضا صفائی (153)i

2.    87/12/1 (07:41)مختل کننده سیستم اعصاب مرکزیست.39%


مکانیسم حرارت بدن انسان چگونه است ؟


مشخصات سوال
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9 دی 86 - 19:27مکانیسم حرارت بدن انسان چگونه است ؟ اطلاعات بیشتر : منبع حرارت بدن از کجاست و چطور همیشه در یک دما ثابت باقی میماند؟تاریخ ایجاد سوال : 9 دی 86 (19:27)تاریخ بسته شدن سوال : 16 دی 86تعداد بازدید :56تعداد پاسخ ها : 7طبقه بندی : علوم » پزشکی- این سوال بسته شده است.

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ایجاد علامتبهترین پاسخ
aslan_sphنام : اصلان امتیاز : 179درصد بهترین پاسخ : 31%اصلان (266)i

86/10/10 (15:27)سلام:دمای بدن در اثر استفاده قندها یا به زبان علمی به علت سوختن قند هاست .دمای بدن از سوختن گلوکز و چربی و اسید های چرب تامین میشه .اولین مرحله سوختن گلوکز است که بدن در صورت در دسترس نبودن گلو کز از چربیها استفاده میکنه .هر غذایی که می خوریم بعد از هضم وجذب به صورت ATPدر سلولها ذخیره میشه که موقع نیاز ATPوارد چرخه سلولی میشه و انرژی ازاد میکنه که میتونه انواع مختلف باشه .گرمای بدن از سوختن این ATPبه وجود میاد .یعنی هنگام واکنش مواد مختلف گرما تولید میشه که بدنو گرم میکنه .البته اگه این دما کم باشه بدن گلوکز میسوزونه تا گرما تولید بشه .تو بدن یه سنسور مانند هایی است که دما رو ثابت نگه میداره.تب هم یه نوع سیستم دفاعی بدنه که موجب میشه انواع میرکرو ارگانیسمهای مضر رو از بین ببره.البته بعصی وقتها هم هست که دمای بدن بالست و تب داره که این مربوط به بیماری نمیشه ولی باز هم یک نوع عملکرد دفاعی هست مثل وقتی که ورزش میکنیم .بدن گردش خون رو بیشتر به سطح اختصاص میده تا گرمای اضافی بدن رو از بین ببره.چون فعالیتهای بدن به وسیله پروتئین انجام میگیره و پروتئین هم در دمای بالا (43-40)شروع به لیز شدن میکنه که این برابر مرگ برای سلولهاست..0%دیگر پاسخ ها
shtabatabaieنام : بنده خدا امتیاز : 280درصد بهترین پاسخ : 9%بنده خدا (157)i

1.    86/10/10 (08:24)هر مکانیسم طبیعی در یک دما بهترین عملکرد را دارد این دما در بدن 37 درجه می باشد
در اثر سوخت و ساز در بدن مقداری گرما حاصل میشود که صرف ثبات دمایی بدن میشه.50%
hamoon896نام : هامون کوروشامتیاز : 91درصد بهترین پاسخ : 0% هامون کوروش (5)i

2.    86/10/10 (10:31)کلا جانداران خون گرم باید یک درجه دمای ثابت داشته باشند و چون انسان جزئ این جانداران است دمای 37 باید ثابت باشد این دما در بدن به خاطر بهترین شرایط سوخت وسازی تعبیه شده و کمتر از آن لرز و بیشتر از آن تب را ایجاد میکند بنابراین شما وقتی فعالیت میکنید دمای داخلی به خاطر سوخت وساز بیشتر بالا میرود و بدن به طور خودکار زمینه عرق کردن و اتلاف دمای داخلی را از طریق آب اتلافی ایجاد میکند یا مویرگهای سطحی بدن پر خون میشود برای همین هم در حالت فعالیت شما پوستتان سرخ میشودتا دمای داخلی به بیرون انتقال داده شود.0%
farhad17نام : ظ غامتیاز : 101درصد بهترین پاسخ : 0%ظ غ (0)i

3.    86/10/10 (22:15)درود.
سعی میکنم تا حد امکان غیر تخصصی و کلی جواب بدم....
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حرارت بدن در اثر مکانیسم های طبیعی سوخت و ساز ها- واکنش شیمیایی مواد مختلف - شکستن مواد آلی - تولید و ترکیب مواد و ... بوجود می آید که شامل هزاران هزار واکنش متوالی است.
دمای تولید شده در بدن حتی در حالت استراحت به حدی بالاست که اگر توسط مکانیسم های خنثی کننده تعدیل نشود تمام سلولهای بدن حتی استخوانها را خواهد سوزاند.
یکی از این هزاران تعدیل کننده های طبیعی آب است که این خواصیت بدلیل وجود پیوند های خاصی است که در ساخت مولکولهای آب بکار رفته است.
و یا انجام واکنش های شیمیایی و فیزیکی در بدن که می توانند گرماگیر یا گرماده باشند و موارد بسیاری دیگر...
و در جواب سوال شما که چطور دما در حد ثابت باقی می ماند به عملکرد سایر اعضای بدن بخصوص غده هیپوفیز مربوط است که با ترشح یا عدم ترشح هورمون با عث تحریک یا عدم تحریک سلولهای هدف شده و باعث بالا رفتن یا کاهش دمای بدن می گردد.
بطور کلی باید گفت تنها یک مکانیسم یا یک فرایند در کنترل اعمال انسان نقش ندارد بلکه مجموعه ای از فرایند های مختلف بطور همزمان و با تاثیر بر رو یکدیگر اعمال مختلف انسان را کنترل می کنند خواه این اعمال ارادی باشد خواه غیر ارادی.
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موفق باشید و بدرود..50%
hr_big2002نام : حامد بیگامتیاز : 177درصد بهترین پاسخ : 2%حامد بیگ (94)i

4.    86/10/12 (12:04)salam
asle hararat bad az sokhto saze ghand dar cellu hast
markaze tanzim hararat gudeie kochak dar maghz ast be name hipotalamius gesmate dide az hararat tavasut kabed ke markaze asli mavad gazaie ast tamin mishe
.0%
pooya111نام : رضا طالبیانامتیاز : 116درصد بهترین پاسخ : 9%رضا طالبیان (21)i

5.    86/10/14 (02:32)منبع حرارت بدن از سوختن مواد غذائی نظیر گلوکز چربی ها است و این حرارت در تمام سلول ها تولید میشه چه عضلات وچه سلول های دیگر یعنی هر سلول زنده ای حرارت تولید می کنه ولی این حرارت در هیپوتالاموس یا پایه مغز کنترل میشه.که برای پایین اوردن حرارت بدن از میکانیسم تابش تعرق دفع حرارت از پوست ودفع حرارت از تنفس استفاده میکنه که در انسان روش تعریق مهمتری روش هست ولی در حیوانی مثل سگ که غدد عرقی نوداره دفع تنفسی مهمترین راه است..0%
cocalosنام : pooya mazloomiامتیاز : 121درصد بهترین پاسخ : 7%pooya mazloomi (35)i

6.    86/10/15 (13:59) دمای طبیعی بدن در طول روز در حال نوسان بین 36.5 و 37.5 c است به این ترتیب که بعد خواب و صبح زود به پایین ترین دما و بعد از ظهر به بیشترین دما میرسد و در طول شبانه روز این تکرار میشود .
تو مغز ما یک مرکز برای کنترل دمای بدن وجود دارد ( که فکر میکنم جزو تشکیلات هیپوتالاموس باشد ) که دمای بدن را با تحریک سوخت و ساز مواد الی ایجاد لرز و انقباض عروق محیطی در سرما و در گرما با کاهش سوخت و ساز و تعریق و گشاد شدن عروق محیطی کنترل میکند ( با تحریک سمپاتیک و یا پارا سمپاتیک ) البته به طور مستقل عروق خونی در مقابل گرما گشاد شده و در سرما تنگ میشوند و تنظیم سوخت و ساز هم تا حد زیادی تحت تاثیر هورمون های تیروئیدی ( t3 , t4 )میباشد بنابراین برای مثال در کم کاری تیروئید عدم تحمل سرما داریم . از طرف دیگر هم فعالیت بدنی و هم غذا خوردن نیز باعث افزایش دمای بدن میشود و معمولا 2 ساعت بعد از غذا خوردن دمای بدن افزایش می یابد . و....0%


تاثیر اریترومایسین بر سلول هاب بدن ما


مشخصات سوال
narges_sungirlنام : نرگس سامتیاز : 255درصد بهترین پاسخ : 0%نرگس س (11)i

29 آبان 87 - 16:42تاثیر اریترومایسین بر سلول هاب بدن ما اطلاعات بیشتر : اریترومایسین دارویی است که خاصیت آنتیبیوتیکی دارد.این دارو از پروتئین سازی در سلول های باکتری جلوگیری می کند،اما بر پروتئین سازی سلول های بدن ما چنین اثری ندارد.این آنتیبیوتیک چه اثری بر سلول های ما دارد؟تاریخ ایجاد سوال : 29 آبان 87 (16:42)تاریخ بسته شدن سوال : 15 آذر 87تعداد بازدید :92تعداد پاسخ ها : 1طبقه بندی : علوم » غیره- این سوال منقضی شده است. و بهترین جواب توسط رای کاربران انتخاب شده است.

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ایجاد علامتبهترین پاسخ
akam22نام : آکام حبیبیامتیاز : 16649درصد بهترین پاسخ : 54%آکام حبیبی (24)i

87/8/29 (17:39)روش بررسی: این كارآزمایی بالینی، روی بیماران مبتلا به پیتریازیس روزه آی تیپیك كه طی دی ماه 1380 لغایت اردیبهشت 1384 به درمانگاه بیمارستان 5 آذر گرگان مراجعه كرده بودند، انجام شد. تعداد كل بیماران 46 نفر بود كه به صورت تصادفی در دو گروه 23 نفری قرار گرفتند. با توجه به دوسوكور بودن مطالعه، درمان به مدت دو هفته برای آنها تجویز و سپس در فواصل 6-2 هفته میزان بهبودی اندازه گیری شد. در گروه مورد داروی اریترومایسین با دوز یك گرم در روز به مدت 14 روز تجویز شد و در گروه كنترل دارونما تجویز شد. داده ها پس از جمع آوری و كدبندی و با استفاده از آزمون Pearson chi-square وارد نرم افزار SPSS 11.5 شد. با توجه به كیفی بودن صفت مورد بررسی و نوع مطالعه از مقایسه نسبت ها برای تجزیه و تحلیل استفاده شد.
یافته ها: طی 2 ، 4 و 6 هفته پس از شروع درمان هر چند در گروه تحت درمان با اریترومایسین نسبت به گروه دارونما نتایج بهتری اخذ شد، ولی تفاوت در پاسخ دهی بین دو گروه از نظر آماری معنی دار نبود.
نتیجه گیری: نتایج این مطالعه نشان دهنده تاثیر ناچیز داروی اریترومایسین در سیر درمانی بیماران مبتلا به پیتریازیس روزه آ می باشد


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ﺑﺮرﺳﯽ ﺗﺎﺛﯿﺮ ﭘﻤﺎد ارﯾﺘﺮوﻣﺎﯾﺴﯿﻦ

www.sid.ir/fa/VEWSSID/J_pdf/69913854606.pdf

مقایسه اثر اریترومایسین و داكسی سیكلین بر آكنه ولگاریس متوسط تا شدید [PDF]

http://www.iranjd.ir/download.asp?code=IJD85936122.100%پاسخی ارسال نشده است.


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