Cross-sectional assessment of the periapical status as related to quality of root canal fillings and coronal restorations in a Yemeni population

The present study aimed to examine the influence of the quality of root canal fillings and coronal restorations on the prevalence of periapical lesions. Materials and Methods: Two hundred digital panoramic radiographs were obtained from the archive of Al?HamziDental Center in Sana’a, Yemen. The final sample consisted of 120 radiographs, and 675 root filled teeth.The quality of root canal fillings was scored according to criteria of length, homogeneity and taper. Coronal status (type of estoration, signs of marginal leakage or decay) was also evaluated. The periapical status was categorized on the basis of presence or absence of radiographical signs of apical periodontitis. Chi-square test was used to determine statistical significance between different parameters. Results: We found that 93.6% of root filled teeth were associated with apical periodontitis. Only 9.2% of root filled teeth were found to have an acceptable standard of root canal fillings, of which 32.3% was also associated to signs of periapical disease. In roots with an unacceptable root canal filling, 95.4% had periapical disease. Teeth with good (14.4%) and poor (32.9%) intra-coronal restorations had apical periodontitis in 93.8% and 97.7% of cases, respectively. Crown restorations were present in 52.7% of root filled teeth, of which 91.0% were associated with periapical lesions. Conclusion: The poor technical quality of root canal fillings and coronal restorations is consistent with a high prevalence of apical periodontitis

Cross-sectional assessment of the periapical status as related to quality of root canal fillings and coronal restorations in a Yemeni population.

Aim: The present study aimed to examine the influence of the quality of root canal fillings and coronal restorations on the prevalence of periapical lesions. Materials and Methods: Two hundred digital panoramic radiographs were obtained from the archive of Al‑HamziDental Center in Sana’a, Yemen. The final sample consisted of 120 radiographs, and 675 root filled teeth.The quality of root canal fillings was scored according to criteria of length, homogeneity and taper. Coronal status (type of restoration, signs of marginal leakage or decay) was also evaluated. The periapical status was categorized on the basis of presence or absence of radiographical signs of apical periodontitis. Chi-square test was used to determine statistical significance between different parameters. Results: We found that 93.6% of root filled teeth were associated with apical periodontitis. Only 9.2% of root filled teeth were found to have an acceptable standard of root canal fillings, of which 32.3% was also associated to signs of periapical disease. In roots with an unacceptable root canal filling, 95.4% had periapical disease. Teeth with good (14.4%) and poor (32.9%) intra-coronal restorations had apical periodontitis in 93.8% and 97.7% of cases, respectively. Crown restorations were present in 52.7% of root filled teeth, of which 91.0% were associated with periapical lesions. Conclusion: The poor technical quality of root canal fillings and coronal restorations is consistent with a high revalence of apical periodontitis

A hybrid algorithm for wave-front corrections applied to satellite-to-ground laser communication

Laser communications hold accurate data rate for ground satellite links. The laser beam is transmitted through the atmosphere. The clear-air turbulence induces a number of phase distortions that damage wave-front. Adaptive optics (AO) treats wave front correction. The nature of AO systems is iterative; it can be integrated in metaheuristic algorithms such as genetic algorithm (GA). This paper presents improved version of algorithm for wave-front corrections. The improved algorithm is based on genetic algorithm (GA) and adaptive optics approach (OA). It is implemented in a computer simulation model called object-oriented matlab adaptive optics (OOMAO). The optimisation process involves best possible GA parameters as a function of population size, iteration count, and the actuators’ voltage intervals. Results show that the application of GA improves the performance of AO in wave-front corrections and the communication between satellite-to-ground laser links as well

Skin Lipoma in an Arabian Leopard (Panthera paradus nimr) Acta Scientiae Veterinariae

ABSTRACT Background: The Arabian leopard (Panthera paradus nimr) is the largest living felid in the arid Arabian Peninsula and classifi ed on the IUCN red list as critically endangered. Unlike felids, neoplasia prevalence in canids such as benign lipoma and malignant liposarcoma has been long and well documented. Only until recently a plethora of reports emerged demonstrating that neoplasia occurrence in wild exotic felids is prevailed more than expected. Soft tissue tumors arise from fatty cells form either a benign lipoma or a dangerously malignant liposarcoma. Alarming though, such cellular transformation might endanger the life of an already endangered animal. Case: An intact Arabian male leopard living in captivity at the Oman wildlife animal breeding center (N23.70 E58.09 A5.80 m) aged approximately 18 years and weight 31 kg was admitted to the veterinary clinic for semen collection and routine physical examination. The animal was identifi ed with two large adjacent subcutaneous masses on the upper rear left limb, clinically resembling that of a lipomatosis. Only one large tissue mass was surgically excised from the base with no incident of bleeding. Gross examination revealed a soft, smooth, rubbery, homogeneous, lack of internal fl uid and whitish color lobule. Morphometry measurement of the mass shows that the weight, diameter, circumference, thickness and surface area were 3.6 gm, 2.6 cm, 10.2 cm, 3 cm and 17.8 cm 3 respectively. On visual examination, neither mucin fl uid nor mucosal ulcerations were detected. Microscopically, dark discrete spots were observed on the anterior central and periphery of the mass surface outgrowth. Moreover, histopathological diagnoses with haematoxylin and eosin (HE), masson fontana (MF) and elastic verrhof van giesson (EVG) revealed normal nuclear and non-granular cytoplasm resembling that of a fatty cell originating from a fat adipose tissue. Adipocytes had reasonable amounts of cytoplasm and well defi ned borders. The nuclei were round to oval shape and no cells were found to be multinucleated. No evidence of high nuclear cytoplasmic ratio was observed. Few lymphocytes and plasma cells were present with no visible lymphatic vessels. Taken together, the lesion was diagnosed as a lobulated soft mass resembling that of an adipose tissue, specifi cally a benign neoplastic lipoma. Discussion: To date not a single report describes maladies in big cats from arid regions. This is the fi rst study to demonstrate the occurrence of neoplasia in a wild felid namely; the Arabian leopard. Additionally, while recent reports have shown neoplasia occurrence in the Panthera subspecies in tropical, polar and temperate zones, this is the fi rst report to manifest the disease in an arid region. The increase in neoplasm frequency in exotic felids is a concerning fact as numerous members of the Panthera family including the Arabian leopard are classifi ed by the IUCN as endangered or critically endangered species. With less than 200 animals in the wild, only 14 founder individuals in captivity and an aged female population the occurrence of lipoma tumors in the Arabian leopard is a worrisome sign. Taken together, the data suggests the rise of uncommon diseases in carnivores and ubiquitously around different climate zones of the world. Thus highlights the importance of routine physical examinations, investing substantially in diagnostic equipment and healthcare endowment in captive exotic felids

Effects of high power electronics converters on PLC signals

The harmonics are generated by the switching operation of large power converters, such as Static Compensator (STATCOM), Static Reactive Power Controller (SVC) and UPFC. These harmonics may cover a wide range of frequencies and it can cause problems of interference with communication systems. Power Line Carrier (PLC) system is one of the systems used in transmission of signals for Tele-potations, Tele-tripping, Tele-control and speech communications. The Signal to Noise Ratio (SNR) of the PLC is based on the noise level at the input of the carrier receiver. These effects of harmonics result in overheating, extra losses in electric machines and capacitors; and over voltage due to excited resonance in the power system. The main source of disturbances resulting from harmonics has been proved to be from a high power converter. This problem becomes more complicated when harmonics are originating in many single source. These harmonics can be propagated throughout the entire interconnected power network. The interference due to large power converter will be superimposed on the background noise at lower levels causing it to reduce the SNR to an unacceptable value. This study deals with the analysis of the waveform of the converters and the methods used to reduce the noise imposed on PLC communication signal. © 2006 Asian Network for Scientific Information