**7. Conclusion**

Sterilization is defined as any process that effectively kills or eliminates almost all microorganisms like fungi, bacteria, viruses, spore forms. Gamma radiation sterilization are mainly used for the sterilization of pharmaceuticals. Depending on their different mechanism of actions, this sterilization method affects the pharmaceutical formulations in different ways. Thus, the sterilization method chosen must be compatible with the item to be sterilized to avoid damage.

Radiation processing has been used commercially for almost forty years. Gamma radiation from cobalt-60 is used to sterilize the medical devices used in operations and other healthcare treatments. Implants, artificial joints, syringes, blood-bags, gowns, bottle teats for premature baby units and dressings are all sterilized using radiation. Gamma irradiation is a physical means of decontamination, because it kills bacteria by breaking down bacterial DNA, inhibiting bacterial division.

The radiation resistance of a microorganism is measured by the so-called decimal reduction dose (D10 value), which is defined as the radiation dose (kGy) required to kill 90% of the total number. Survival fraction of the microorganisms is reversely proportional with the absorbed dose. Doses for sterilization should be chosen according to the initial bioburden, sterility assurance level (SAL) and the radiosensitivity of microorganisms. Temperature plays a major role in the radiosensitivity of microorganisms. As a general rule, microorganisms are less radiosensitive when irradiated at low temperatures

On the other hand, radiation sterilization of tissue grafts has been implemented in some tissue banks, and a dose of 25 kGy has been used in many of these tissue banks. The advantage of radiation sterilization is that it allows the processing of grafts, which have been previously sealed or tightly closed in special wrappings. Such procedures prevent any accidental recontamination during packing. Food also can is sterilized by gamma irradiation and the process exposing food to ionizing radiation to destroy microorganisms, bacteria, viruses, or insects that might be present in the food. Irradiated food does not become radioactive, but in some cases there may be subtle chemical changes. The use of low-level

In addition, the preparation of polymer films containing disperse nanoparticles has a great interest. The importance of these nanocomposites is due the mechanical, electrical, thermal, optical, electrochemical, catalytic properties that will differ markedly from that of the component materials. For example, the synthesis of Sb2S3 nanoparticles by sonochemical route under ambient air from solution containing antimony chloride as metal source and thioacetamide as a sulfur source produced amorphous powder with monodiperse nanospheres, whose diameters were calculated in the range of 300-500 nm. Films of PVC with Sb2S3 (PVC/Sb) nanoparticles were exposed to gamma irradiation at sterilization dose and the effects of the nanoparticles on the viscosity average molar mass (Mv) of sterilized PVC were studied. The results revealed less chain scissions occur in PVC/Sb films at 0.30 wt% concentration. At sterilization dose (25 kGy) was calculated a decrease of 67% in scissions per original molecule of PVC. No information about use of Sb2S3 in the radiolytic stabilization of polymers has been published and consequently the mechanism of radiolytic stabilization effect of these nanoparticles is not clear. However, some probable reactions

Sterilization is defined as any process that effectively kills or eliminates almost all microorganisms like fungi, bacteria, viruses, spore forms. Gamma radiation sterilization are mainly used for the sterilization of pharmaceuticals. Depending on their different mechanism of actions, this sterilization method affects the pharmaceutical formulations in different ways. Thus, the sterilization method chosen must be compatible with the item to

Radiation processing has been used commercially for almost forty years. Gamma radiation from cobalt-60 is used to sterilize the medical devices used in operations and other healthcare treatments. Implants, artificial joints, syringes, blood-bags, gowns, bottle teats for premature baby units and dressings are all sterilized using radiation. Gamma irradiation is a physical means of decontamination, because it kills bacteria by breaking down bacterial

The radiation resistance of a microorganism is measured by the so-called decimal reduction dose (D10 value), which is defined as the radiation dose (kGy) required to kill 90% of the total number. Survival fraction of the microorganisms is reversely proportional with the absorbed dose. Doses for sterilization should be chosen according to the initial bioburden, sterility assurance level (SAL) and the radiosensitivity of microorganisms. Temperature plays a major role in the radiosensitivity of microorganisms. As a general rule,

On the other hand, radiation sterilization of tissue grafts has been implemented in some tissue banks, and a dose of 25 kGy has been used in many of these tissue banks. The advantage of radiation sterilization is that it allows the processing of grafts, which have been previously sealed or tightly closed in special wrappings. Such procedures prevent any accidental recontamination during packing. Food also can is sterilized by gamma irradiation and the process exposing food to ionizing radiation to destroy microorganisms, bacteria, viruses, or insects that might be present in the food. Irradiated food does not become radioactive, but in some cases there may be subtle chemical changes. The use of low-level

microorganisms are less radiosensitive when irradiated at low temperatures

may be going on under gamma irradiation.

**7. Conclusion** 

be sterilized to avoid damage.

DNA, inhibiting bacterial division.

irradiation as an alternative treatment to pesticides for fruits and vegetables that are considered hosts to a number of insect pests including fruit flies and seed weevils. The irradiation produces no greater nutrient loss than what occurs in other processing methods. However, the irradiation reduces the vitamin content of food, the effect of which may be indirect in that inadequate amounts of antioxidant vitamins (such as C, E, and β-carotene) may be available to counteract the effects of free radicals generated by normal cell metabolism. In addition, the most affected lipids during irradiation are thus the polyunsaturated fatty acids that bear two or more double bonds.

When radiation is used for the sterilization of medical devices, the compatibility of all of the components has to be considered. Ionizing radiation not only kills microorganisms but also affects material properties. When the polymer systems are submitted to sterilization by gamma radiation (25 kGy dose), their molecular structures undergo modification mainly as a result of main chain scission and crosslinking effects. Both processes coexist and either one may be predominant depending not only upon the chemical structure of the polymer, but also upon the conditions like temperature, environment, dose rate, etc., under which irradiation is performed.

The protection of polymers against sterilization dose requires efficient additives preventing and/or stopping chain reaction type oxidative degradation. Primary and secondary antioxidants work well here in synergy. Polymer blend and nanoparticles also may be used in radiolytic stabilization of polymer used in medical devices. Commercial raw materials are available for radiation-sterilizable medical devices made of polyolefins and other thermoplastics. Similarly, polymer compounds of suitable formulae are offered commercially for high-dose applications in nuclear installations.

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**10** 

 *India* 

**Induction of Genetic Variability** 

**with Gamma Radiation and Its** 

*1Department of Botany, University of Pune, Pune (M.S.), 2Dada Patil Mahavidyalaya Karjat, Dist- A. Nagar (M.S.),* 

K. N. Dhumal1 and S. N. Bolbhat2

**Applications in Improvement of Horsegram** 

Induced mutation is one of the best alternatives for the improvement of horsegram as it can help to regenerate and restore the variability, which is generally lost in the process of adaptation to various stresses. Genetic variability is the most essential prerequisite for any successful crop improvement programme as it provides spectrum of variants for the effective selection, which can be achieved through the processes of hybridization,

Genetic variability has been exhausted in horsegram due to natural selection and hence conventional breeding methods are not fruitful (Wani and Anis, 2001). Legumes generally loose different alleles for high productivity, seed quality, pest and disease resistance during

Gamma sources are used to irradiate a wide range of plant materials, like seeds, whole plants, plant parts, flowers, anthers, pollen grains and single cell cultures or protoplasts. Radiations have been used successfully to induce useful mutations for plant breeding. The lower doses/ concentrations of the mutagenic treatments could enhance the biochemical components, which are used for improved economic characters (Muthusamy *et al*., 2003). Gamma radiation can induce useful as well as harmful effects on crops so there is need to predict the most beneficial dose for improvement of specific traits of crop plants (Jamil and

Improvement in yield and productivity of pulses is the need of the hour, but for this marginal land, aberrant rainfall, non availability of improved seeds, less or no input and poor crop management are the main constraints. Amongst pulses horsegram (*Macrotyloma uniflorum* (Lam.) Verdc) is highly neglected in India and hence require more emphasis on its improvement as it has nutritional, medicinal and fodder value. In Maharashtra, during the year 2008-2009, horsegram was cultivated on 0.466 lakh ha with annual production of 0.3232

Horsegram is drought tolerant and having good nitrogen fixing ability, but receives a low priority in cropping system, soil types etc. It is grown in *kharif* and *rabbi* seasons, as main

**1. Introduction** 

Khan, 2002).

recombination, mutation and selection.

the processes of adaptation to environmental stress.

lakh tones. The average yield per hactar was 693.56 Kg.

