Introduction: Long-term clinical evaluation of dental implants and their surrounding structures is of utmost importance to acquire knowledge about reasons for implant success and failure.However, accurate and reproducible results are difficult to obtain. The aim of the present study was to examine bone height around endosseous implants on digital conventional radiographs (DCR) and direct digital subtraction images (DSI) prior to loading.Materials and methods: In this experimental study, bone height around 10 implants in 6 patients was assessed by 2 observers. Standardized digital radiographs were obtained just a week and 3 months postoperatively and subtracted by means of EMAGO software. Then the observers evaluated bone height on DCRs and DSIs. MINITAB software and paired t-test were used for statistical analysis (a=0.05).Results: Comparative evaluation of bone height indicated significantly higher values on DCR than on DSI (p value=0.002). The observers also had statistically significant variability in this assessment (p value=0.00003).Conclusion: DSI demonstrated lower values of linear measurement of bone height around endosseous implants compared with DCR. Interobserver variability should be considered when comparing values from follow-up studies.

In this paper, we review some research works on exploring image processing in digital spaces using fixed point theorems. The basic concepts of digital images are mentioned. Moreover, we prove some theorems on digital metric spaces by replacing the conditions in the previously established theorem with a suitable condition.

Background & Aim: The majority of carious lesions are not well-defined radiolucencies. Approximately 40% demineralization is required for radiographic detection of a lesion. The actual depth of penetration of carious lesion is deeper than may be detected radiographically. However, digital subtraction images permit to detect 1-5% decrease of mineral mass per unit volume. The goal of the present study was to evaluate the accuracy of digital subtraction radiography in the detection of dental demineralization in vitro.Methods & Materials: This study was based on observational-diagnostic method which was done on 30 extracted human teeth, categorized in two groups A and B, each having 15 members. In each of teeth, one approximal enamel demineralization lesion was induced using an acidified system (PH=4.8). Direct digital radiography were obtained under standardized condition of teeth before demineralization. After 7 days, the teeth of group B and after 42 days, group A removed from acid and new radiographs were taken. The images of the 7th and 42nd days were subtracted from the baseline radiograph (before creation of the lesion). Then teeth were histologically evaluated. Direct digital and subtraction images were interpreted by three observers to detect presence or absence of the lesion, then the diagnostic accuracy of both methods was determined.Results: After 7 days, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value for incipient lesions in direct digital radiography were 0%, 80%, 40%, 0% and 44% respectively and in digital subtraction radiography were 66.7%, 86.7%, 76.7%, 83.4% and 72.3% respectively. However after 42 days the sensitivity, specificity and accuracy of both methods were 100%.Conclusion: digital subtraction radiography has a fairly acceptable accuracy in detection ofthe incipient proximal lesions in comparison with DDR. For moderate proximal lesions DSR has the same accuracy as DDR.

In a fuzzy metric space (X, M,*), where * is a continuous t-norm, a locally fuzzy contraction mapping is defined. It is proved that any locally fuzzy contraction mapping is a global fuzzy contractive. Also, if f satisfies the locally fuzzy contractivity condition then it satisfies the global fuzzy contractivity condition.

Background and Aim: Whole Body Vibration (WBV) is more attended as a new exercise modality helping improvement in neuro-muscular performance, but so far, its immediate effect indirectly concurrent with different external load (EL) on maximum voluntary contraction (MVC) and upper limb electromyography (EMG) in not known. The purpose of the spresent study was to investigate the immediate effect of WBV on maximumisometric contraction and upper limb EMG indifferent contraction forces.Materials and Methods: In 15 young healthy men, dominant biceps randomly underwent isometric contaction with supination of forearm and 90 degrees of elbow flexion while receiving no WBV or WBV with a frequency of 50 Hz and low amplitude (4 mm) for 60 seconds (i.e. two thirty-second phase with an interval of 20-second-rest) in three different modes: without EL, with an EL of 10% of primary MVC, and finally with an EL of 20% of primary MVC. In the meantime, EMG activity of the muscle was recorded and once the whole exercise protocol was terminated, MVC was measured and its EMG activity was recorded simultaneously with MVC.Results: WBV without EL showed a significant increase in biceps MVC compared with no WBV and no EL (P=0.006), wheras in WBV the comparison of an EL of 10% of primary MVC and that of 20%, despite rendering higher rate of MVC, is not statistically significant. On the other hand, WBV without EL revealed a significant improvement in biceps RMS (P=0.001). The same was true in WBV with an EL of 20% of MVC (P=0.032). The rate of ΔFMED with WBV or without WBV, and with an EL of 20%, was statistically more significant than without WBV, with an external load of 10%, and this significancy with vibration was P=0.011 and without vibration was P=0.016. Meanwhile, ΔFMED was significant with WBV and with an external load of 20% of MVC compared with WBV and 10% of MVC (P=0.023).Conclusion: It seems that a single session of WBV reults in an immediate increase of MVC and EMG of biceps bracheiand applying ELs of 10% and 20% of MVC with WBV did not significantly increase in the present study, but it leadsto more increase of MVC and EMG. Also, the effect of an EL of 20% of MVC in this increase is more tangible than 10% of MVC.

High gain Balun-low-noise-amplifier (LNA) is proposed for tuner of digital televisions (DTVs). The proposed Balun-LNA is based on CS-CG (common-source-common-gate) structure. To improve the isolasion and frequency response, Balun-LNA has cascode transistors before load resistors. Balun-LNA uses current-bleeding circuit to increasie transconductance of CS transistor, so that current-bleeding transistor has transconductance of N-1 times larger than transconductance of cascode transistor. Thereby, transconductance and current of CS transistor are increased N times, as N-1 times of current pass to current-bleeding transistor. Therefore current of CG and CS stages stay identical. Also, Balun-LNA employs a positive feedback to satisfy input impedance matching and CG transistor has higher transconductance. By increasing transconductance of CS and CG transistors, the proposed Balun-LNA achieves to high voltage gain. Accordingly, CG and CS tansistors have symmetrical currents and loads at the differential output of the proposed Balun-LNA. Symmetrical loads cause the balanced differential outputs. This proposed Balun-LNA is designed in 90-nm CMOS technology and covers the frequency range of 40 MHz to 1GHz. This Balun-LNA achieves the voltage gain of 22.6 dB, S11 of less than -10 dB and the Minimum NF of 5 dB. This Balun-LNA operates at the nominal supply voltage of 2.2v.