Relationship between maternal periodontal disease and Apgar score of newborns

Shirmohammadi, Adileh,Abdollahifard, Sedigeh,Chitsazi, Mohammad-Taghi,Behlooli, Sepideh Korean Academy of Periodontology 2012 Journal of Periodontal & Implant Science Vol.42 No.6

Purpose: The aim of this study was to evaluate the relationship between maternal periodontal disease and the health status of newborns using Apgar scores. Methods: One hundred pregnant women with periodontal disease were included in the case series and 100 pregnant women without periodontal disease were placed in the control group, respectively. The periodontal parameters of bleeding on probing (BOP), clinical attachment loss (CAL), probing depth (PD), birth weight, and Apgar scores were recorded in both groups. T-tests and Pearson's correlation coefficient were used to determine the birth weight odds ratio to analyze the relationship between the periodontal parameters of BOP, CAL, and PD on the one hand and an Apgar score of less than 7. An unpaired Student's t-test was used to analyze differences in means between the case and control groups using SPSS ver. 13. Results: The means of the ages, periodontal pocket depths, attachment loss, areas with BOP, Apgar score in the first 5 minutes and infant birth weight exhibited statistically significant differences between the case and control groups. The ratio of an Apgar score of <7 to periodontal disease was 3.14; the ratio of low birth weight risk in mothers with periodontal disease to that in mothers without periodontal disease was 2.74. Pearson's correlation coefficient revealed a significant correlation between the infant birth weight and BOP, CAL, and PD of the mother. In addition, there was a significant correlation between the Apgar score and BOP, CAL, and PD and also between the Apgar score and infant birth weight. Conclusions: The results of this study showed a significant relationship between periodontal disease and infant birth weight; in addition, there was a significant relationship between the periodontal indexes of BOP, CAL, and PD on the one hand and the Apgar score on the other.

Low Dissipative Snubber Using Flyback-Type Transformer for 10 kV IGCT in 7 MW Wind Turbine Systems

Shirmohammadi, Siamak,Suh, Yongsug IEEE 2018 IEEE TRANSACTIONS ON POWER ELECTRONICS - Vol.33 No.7

<P>10 kV integrated gate-commutated thyristor (IGCT) has been recently developed and has the potential to push wind turbine systems to higher power and voltage rating. Converters employing IGCTs need snubber and over-voltage protection circuit to limit the rate of current's rising and peak over voltage across IGCT during turn-on and -off state, respectively. The conventional resistor-capacitor-diode (RCD) snubber which is used in such power converter dissipates a significant amount of power. In order to reduce the amount of energy lost by the conventional RCD snubber, this paper proposes flyback-type snubber. Flyback-type snubber not only meets all of the IGCTs characteristics during on- and off-state but also significantly saves the power loss. The proposed flyback-type snubber can save up to 73% of the loss in conventional <I>di/dt</I> snubber circuit according to the PLECS magnetic simulation of three-level neutral point clamped grid side converter. The experiments are performed using IGCT stack. Flyback transformer yields the effectiveness of the proposed snubber in wind turbine systems.</P>

Comparison of pain intensity of anterior middle superior alveolar injection with infiltration anesthetic technique in maxillary periodontal surge

Shirmohammadi, Adileh,Faramarzi, Masoumeh,Lafzi, Ardeshir,Kashefimehr, Atabak,Malek, Sepideh Korean Academy of Periodontology 2012 Journal of Periodontal & Implant Science Vol.42 No.2

Purpose: The aim of the present clinical trial was to compare pain during injection of anterior middle superior alveolar (AMSA) technique with that of infiltration injection technique in the maxilla in periodontal flap surgeries of patients referring to the Department of Periodontics, Faculty of Dentistry, Tabriz University of Medical Sciences. Methods: Twenty subjects with an age range of 20 to 40 years were selected for the present study. One side of the maxilla was randomly selected as the test side and the other as the control side using a flip of a coin. AMSA technique was used on the test side and infiltration technique was used on the control side for anesthesia. On both sides 2% lidocaine containing 1:80,000 epinephrine was used for anesthesia. The operator obtained the visual analogue scale for each patient immediately after the injection and immediately after surgery. Data was analyzed using descriptive statistical methods (frequency percentages, means and standard deviations) and Wilcoxon's test using SPSS ver. 13 (SPSS Inc.). Statistical significance was defined at P<0.05. Results: There were no statistically significant differences in pain during injection between the two techniques (P=0.856). There were statistically significant differences in postoperative pain between the two injection techniques (P=0.024). Conclusions: Postoperative pain in AMSA injection technique was less than that in the infiltration technique. Therefore, the AMSA technique is preferable in the periodontal surgeries for the anesthesia of palatal tissues given the fact that it has other advantages, too.

Relationship between maternal periodontal disease and Apgar score of newborns

Adileh Shirmohammadi,Sedigeh Abdollahifard,Mohammad-Taghi Chitsazi,Sepideh Behlooli 대한치주과학회 2012 Journal of Periodontal & Implant Science Vol.42 No.6

Purpose: The aim of this study was to evaluate the relationship between maternal periodontal disease and the health status of newborns using Apgar scores. Methods: One hundred pregnant women with periodontal disease were included in the case series and 100 pregnant women without periodontal disease were placed in the control group, respectively. The periodontal parameters of bleeding on probing (BOP), clinical attachment loss (CAL), probing depth (PD), birth weight, and Apgar scores were recorded in both groups. T-tests and Pearson’s correlation coefficient were used to determine the birth weight odds ratio to analyze the relationship between the periodontal parameters of BOP, CAL, and PD on the one hand and an Apgar score of less than 7. An unpaired Student’s t-test was used to analyze differences in means between the case and control groups using SPSS ver. 13. Results: The means of the ages, periodontal pocket depths, attachment loss, areas with BOP, Apgar score in the first 5 minutes and infant birth weight exhibited statistically significant differences between the case and control groups. The ratio of an Apgar score of <7 to periodontal disease was 3.14; the ratio of low birth weight risk in mothers with periodontal disease to that in mothers without periodontal disease was 2.74. Pearson’s correlation coefficient revealed a significant correlation between the infant birth weight and BOP, CAL, and PD of the mother. In addition, there was a significant correlation between the Apgar score and BOP, CAL, and PD and also between the Apgar score and infant birth weight. Conclusions: The results of this study showed a significant relationship between periodontal disease and infant birth weight;in addition, there was a significant relationship between the periodontal indexes of BOP, CAL, and PD on the one hand and the Apgar score on the other.

Public Awareness of Early and Late Complications of Type 2 Diabetes - Application of Latent Profile Analysis in Determining Questionnaire Cut-Off Points

Nasrin Shirmohammadi 질병관리본부 2018 Osong Public Health and Research Persptectives Vol.9 No.5

Objectives A questionnaire was designed to determine public understanding of early and late complications of Type 2 diabetes mellitus (T2DM). Methods A cross-sectional study was performed in participants who were selected using a multi-stage sampling method and a standard questionnaire of 67 questions was proposed. An expert panel selected 53 closed-ended questions for content validity to be included in the questionnaire. The reliability of the questionnaire was tested using Cronbach’s alpha coefficient giving a score of 0.84. Results Of the 825 participants, 443 (57.6%) were male, and 322 (41.87%) were 40 years or more. The proportion of low-, moderate- and high- awareness about T2DM and its complications was 29.26%, 62.68%, and 8.06%, respectively. Friends (56.31%) and internet and social networks (20.55%) were the 2 major sources of awareness, respectively. The medical staff (e.g., physicians) had the lowest share in the level of public awareness (3.64%) compared to other sources. Conclusion These results present data that shows the general population awareness of T2DM is low. Healthcare policymakers need to be effective at raising awarenes of diabetes and it should be through improved education.

Flyback-type Snubber of High Efficiency for 10kV IGCT in 7MW Wind Turbine Systems

Siamak Shirmohammadi,Yongsug Suh(서용석) 전력전자학회 2015 전력전자학술대회 논문집 Vol.2015 No.07

Characteristics of Time Varying Magnetic Fields in Thyristor Rectifiers of 19kA in Chlor-Alkali Industry

Siamak Shirmohammadi,Yongsug Suh 전력전자학회 2014 전력전자학술대회 논문집 Vol.2014 No.7

Cascaded Snubber Scheme using Flyback Type Transformer for 10kV IGCT Applications

Siamak Shirmohammadi,Yongsug Suh 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

IGCT semiconductor is the best candidate to expand the power and voltage rating of future wind turbine systems. IGCT-based converters need snubber and RCD clamp circuit to decay the sharpness of current and voltage stress across IGCT semiconductor at the on and off time respectively. Such a clamp circuit not only need complex IGCT stack design but also has negative impact on overall system loss of converters. In response, this paper suggests a version of flyback clamp snubber comprising cascaded flyback transformers which limit the rate of current rise sequentially. The cascaded flyback clamp snubber meets all of the IGCTs requirements at the on and off time but it consumes significantly lower power. The benefit of cascaded type over basic flyback clamp snubber is the perfect voltage distribution over 10kV SiC clamp diodes. These diodes recover the magnetizing energy of flyback transformer in to the DC-link unit. 10kV IGCT and related diode have been used for simulation and experiment using RCD and flyback clamp snubber circuits to prove the advantages of cascaded version.

Energy Recovery Flyback Type Snubber for 10kV IGCT in 7MW Wind Turbine Systems

Siamak Shirmohammadi,Kihyun Lee,Yongsug Suh 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

10kV IGCT has been recently developed and has the potential to push wind turbine systems to higher power and voltage rating. Converters employing IGCTs need snubber and OVP circuit to limit the rate of rise of current and peak over voltage across IGCT during turn on and off state respectively. The conventional RCD snubber which is used in such power converter dissipates a significant amount of power. In order to reduce the amount of energy lost by conventional RCD snubber, this paper proposes a flyback-type snubber circuit that not only meets all of the IGCTs characteristics during on and off-state but also significantly saves the power loss. Loss analysis of conventional di/dt snubber and OVP circuit is performed for the 3-level NPC type back-to-back VSC supplied from grid voltage of 6.9kV. In comparison with the conventional snubber, flyback type snubber has a fewer number of components and improved efficiency leading to a reliable and efficient wind turbine systems.

Software for biaxial cyclic analysis of reinforced concrete columns

Fatemeh Shirmohammadi,Asad Esmaeily 사단법인 한국계산역학회 2016 Computers and Concrete, An International Journal Vol.17 No.3

Realistic assessment of the performance of reinforced concrete structural members like columns is needed for designing new structures or maintenance of the existing structural members. This assessment requires analytical capability of employing proper material models and cyclic rules and considering various load and displacement patterns. A computer application was developed to analyze the non-linear, cyclic flexural performance of reinforced concrete structural members under various types of loading paths including non-sequential variations in axial load and bi-axial cyclic load or displacement. Different monotonic material models as well as hysteresis rules, were implemented in a fiber-based moment-curvature and in turn force-deflection analysis, using proper assumptions on curvature distribution along the member, as in plastic-hinge models. Performance of the program was verified against analytical results by others, and accuracy of the analytical process and the implemented models were evaluated in comparison to the experimental results. The computer application can be used to predict the response of a member with an arbitrary cross section and various type of lateral and longitudinal reinforcement under different combinations of loading patterns in axial and bi-axial directions. On the other hand, the application can be used to examine analytical models and methods using proper experimental data.