Background: One remaining grey zone in locoregional breast irradiation is whether to irradiate internal mammary lymph nodes (IMN) in the lack of gross involvement as well as optimum dosimetric recommendations for IMN irradiation. Our study aimed to assess whether IMNs are incidentally irradiated during locoregional breast irradiation, and whether this non-intended irradiation could contribute to lower IMN recurrence risk.Method: This retrospective study was conducted on 137 adult female patients treated at Alexandria Main University Hospital who had pathologically proven breast cancer. Patients should have undergone surgery and were proven to be: T3 (tumor > 5 cm), had positive axillary lymph nodes (ALNs; ≥ 1 ALN involvement) or had positive surgical margins, from January 1st, 2015, to December 31st, 2017. IMNs were delineated, and the IMN mean dose was recalculated. Data were analyzed using SPSS Ver. 25 and data was considered statistically significant at a P-value of ≤ 0.05.Results: Only the IMN mean dose percent, at a cutoff dose of 28.5% mean dose percent, was associated with significant reduction in the risk of IMN recurrence (P = 0.05). Other factors including tumor site, size, grade, or nodal status were not associated with higher risk of recurrence.Conclusion: Although the indication of IMN irradiation is still debatable, our results suggest that a minimum prescribed dose percent of 28.5% is needed to reduce the risk of IMN recurrence in patients with no IMN gross involvement. Yet, studies with larger sample size are needed to better characterize optimum IMN dosimetric criteria.

In last two-decade preparation of materials by microwave irradiation became subject of interest among scientists and engineers. This method offers several advantages in comparison to conventional method including saving in time and energy. In addition, microwave irradiation is very selective in heating and consequently is very efficient in material processing relative to conventional heating. In the present study the CU2(OH)3NO3, gerhardtit, which is a precursor for the preparation of multicomponet oxide with spinel structure was prepared by microwave irradiation from mixture of aluminum nitrate and copper oxide. The effect of irradiation time and the mole ratio of substrates in the preparation of gerhardtit have been investigated. The prepared materials were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR). The results compared to the data obtained for the same material, prepared by conventional heating.

Introduction: Although dental caries is a preventable disease, it is still common and remains a public health problem. One of the potentially effective preventive measures is the use of lasers. The purpose of this study was to review the studies about use of laser irradiation on the inhibition of carious lesions and the effectiveness of different commercial laser type (Nd: YAG, CO2, and Argon).Method: A literature search included journal databases, existing systematic reviews, and studies identified by content experts. Studies meeting inclusion criteria were assessed for quality.Results: Some studies have demonstrated the potential preventive effect of laser irradiation on sound enamel; the effect of irradiation on white spot lesions is still unclear. The effects of irradiating demineralized enamel surfaces coupled with the use of topical fluoride application is also still unclear and further research needs to be conducted in this area. Laser irradiation alone can significantly enhance acid resistance of sound enamel surfaces and prevent caries progression.Conclusion: Combined use of topical fluoride application and laser irradiation on sound enamel surfaces has provided the best protection against caries initiation and progression. Laser irradiation was of limited value in managing incipient carious lesions. Argon laser use may be easier clinically due to its large and visible beam diameter, which allows for irradiation of the whole surface of the tooth instead of the overlapping and time consuming pattern of the CO2 laser.

Introduction: Different environmental factors such as drugs, ionizing radiation, etc can induce apoptosis.In the present study the effects of dose- rate and post-irradiation incubation time on gamma radiation inducedapoptosis in human breast carcinoma cell line (T-47D) (Invasive ductal carcinoma) was investigated. Material and Methods: The T-47D cells were cultured in T25 flasks and during log phase of growth,the cells were counted and exposed to 4,8,12 and 16Gy gamma radiation. Untreated and etoposide treated cellsserved as negative and positive controls, respectively. At 24,48 and 72 hours post irradiation, the cells wereharvested and stained with HO/PI and AO/PI for morphological and flow cytometric analysis, respectively.Absolute and relative numbers of live(L), apoptotic (Ap) and dead (D) cells were determined using the abovementioned methods and reported as Mean ± SD. Results: In comparison to normal controls, gamma radiation inhibited growth of T-47D cells in a dose andpost-irradiation incubation time dependent manner which was defined by reduction of cell proliferation justafter exposure that continued for 48 hours and was followed by cell count reduction. The relation between irradiation dose and apoptosis induction was not linear and inverted at 8Gy after 48 hours post irradiation.Therefore, maximum apoptotic response (%) occured during 48 hours after expossure to 8Gy. However,relative numbers of a live and dead cells decreased and increased respectively in a dose and time dependentmanner. Conclusions: The present study revealed that gamma-irradiation could induce apoptosis in T-47D cellline and the rate of apoptosis was radiation dose dependent but this relation was not linear and in higherdoses became inverted . However, cell viability and death were dose and time dependent.