Prevalence of methicillin-resistant Staphylococcus aureus in Iranian children: a systematic review and meta-analysis

Sarrafzadeh, Farhad,Sohrevardi, Seyed Mojtaba,Abousaidi, Hamid,Mirzaei, Hossein The Korean Pediatric Society 2021 Clinical and Experimental Pediatrics (CEP) Vol.64 No.8

Background: Antibiotic resistance is associated with longer hospitalizations, higher treatment costs, and increased morbidity and mortality rates. Purpose: This study aimed to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in Iranian children. Methods: International databases, including Web of Science, PubMed, Embase, and Scopus, and Iranian databases, including Scientific Information Database (www.sid.ir), Magiran, and Iranian Database for Medical Literature (idml.research.ac.ir), were systematically searched for articles published between January 2000 and August 2019. Sources of heterogeneity were determined using subgroup analysis and meta-regression. Results: Overall, 343 studies were identified; of them, 20 were included in the meta-analysis to estimate the pooled prevalence. The pooled prevalence of MRSA was 42% (95% confidence interval [CI], 29-55) among culture-positive cases of S. aureus, 51% (95% CI, 39-62) in hospitalized children, and 14% (95% CI, 0.05-27) in healthy children. Conclusion: The overall pooled prevalence of MRSA in children was 42%. Appropriate infection control measures and effective antibiotic therapy are needed.

Evaluation of various techniques for microalgal biomass quantification

Sarrafzadeh, M.H.,La, H.J.,Seo, S.H.,Asgharnejad, H.,Oh, H.M. Elsevier Science Publishers 2015 Journal of biotechnology Vol.216 No.-

Biomass concentration is one of the most important parameters in the biotechnology processes. Its measurement relies on the physical, chemical or biological properties of the cells. Several techniques were applied in this work to measure the cell concentration of four microalgae: Botryococcussp., Botryococcusbraunii, Chlorella vulgaris, and Ettlia sp. The experiments were performed using samples taken from a chemostat for each strain to provide microalgal cell suspensions in a stable physiological state and concentration. The dry cell weight (DCW) was used as the reference method for the evaluation of other methods. The two commercial sensors used to determine optical density and dielectric permittivity showed a broad effective measurement range up to more than 20gl<SUP>-1</SUP>. A Red-Green-Blue model analysis of microalgal digital images in combination with Fourier equation significantly extended the measurements range up to 6gl<SUP>-1</SUP>. Cell count using a flow cytometer showed a broad range of linearity to DCW in washed samples, but other counting methods using hemocytometer and microscopic automated count were limited. Finally, the oxygen production rate, representing the photosynthetic activity, showed a linear regression with DCW at cell concentrations lower than 1gl<SUP>-1</SUP>.

Aeration Effects on Metabolic Events during Sporulation of Bacillus thuringiensis

Mohammad H. Sarrafzadeh,Sabine Schorr-Galindo,Hyun-Joon La,오희목 한국미생물학회 2014 The journal of microbiology Vol.52 No.7

The metabolism of Bacillus thuringiensis during its sporulation process was investigated under different concentrations of oxygen. At the beginning of sporulation, the aeration conditions were regulated to obtain different oxygentransfer rates (OTR) in four separate fermentations, representing interrupted, limited, non-limited, and saturated oxygenation, respectively. A higher OTR resulted in a higher pH, up to about 9 in the case of saturated oxygenation,while the interrupted oxygenation resulted in a significantly acidic culture. In contrast, the absence of oxygen resultedin rapid sporangia lysis and caused acidification of the medium, indicating a distinctly different sporangia composition and different metabolism. The bacterium also showed different CO2 production rates during sporulation, although a maximum point was observed in every case. With a higher OTR, the maximal value was observed after a longer time and at a lower value (40, 26, and 13 mmol/L/h for limited, non-limited, and saturated cases, respectively). Despite the exhaustion of glucose prior to the sporulation phase, the interrupted oxygenation resulted in acetate, lactate, and citrate in the medium with a maximum concentration of 4.8,1.3, and 5.0 g/L, respectively. Notwithstanding, while themetabolic events differed visibly in the absence of oxygen,once sporulation was triggered, it was completed, even in the case of an interrupted oxygen supply.

Optimal strategies for bioremediation of nitrate-contaminated groundwater and microalgae biomass production

Rezvani, Fariba,Sarrafzadeh, Mohammad-Hossein,Seo, Seong-Hyun,Oh, Hee-Mock Springer-Verlag 2018 Environmental Science and Pollution Research Vol.25 No.27

Phosphorus optimization for simultaneous nitrate-contaminated groundwater treatment and algae biomass production using <i>Ettlia</i> sp.

Rezvani, Fariba,Sarrafzadeh, Mohammad-Hossein,Seo, Seong-Hyun,Oh, Hee-Mock Elsevier Applied Science 2017 Bioresource technology Vol.244 No.1

<P><B>Abstract</B></P> <P>The effects of phosphorus concentration on the cell growth, nutrient assimilation, photosynthetic parameters, and biomass recovery of <I>Ettlia</I> sp. were evaluated with batch experiments using groundwater, 50mg/L of N-NO<SUB>3</SUB> <SUP>−</SUP>, and different concentrations of P-PO<SUB>4</SUB> <SUP>3−</SUP>: 0.5, 2.5, 5, and 10mg/L. The maximum biomass productivity and phosphorus removal rate were 0.2g/L/d and 5.95mg/L/d, respectively, with the highest phosphorus concentration of 10mg/L. However, a phosphorus concentration of 5mg/L (N:P=10) was sufficient to ensure an effective nitrogen removal rate of 11mg/L/d, maximum growth rate of 0.88/d, and biomass recovery of 0.72. The appropriate hydraulic retention time was considered as 4days on a large scale to meet the effluent limitation demands of water. While nitrogen depletion had a significant effect on the photosynthetic parameters and ratio of chlorophyll <I>a</I> to dry cell weight during the stationary phase, the effect of phosphorus was negligible during the cultivation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Applying <I>Ettlia</I> sp. for biomass production and nitrate removal from groundwater. </LI> <LI> Using batch glass columns with a surface area of 7.9×10<SUP>−3</SUP> m<SUP>2</SUP> and a working volume of 1.7×10<SUP>−3</SUP> m<SUP>3</SUP>. </LI> <LI> 5mg/L of P (N:P=10) was sufficient to ensure an effective N removal rate of 11mg/L/d. </LI> <LI> A hydraulic retention time of 4days was considered for a large scale application. </LI> <LI> Biomass recovery of <I>Ettlia</I> sp. by easy auto-flocculation reached up to 0.72. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Phosphorus optimization for simultaneous nitrate-contaminated groundwater treatment and algae biomass production using Ettlia sp.

Rezvani, Fariba,Sarrafzadeh, Mohammad-Hossein,Seo, Seong-Hyun,Oh, Hee-Mock Elsevier Science B.V., Amsterdam. 2017 Bioresource technology Vol.224 No.-

Effect of sweep angle on bifurcation analysis of a wing containing cubic nonlinearity

Irani, Saied,Amoozgar, Mohammadreza,Sarrafzadeh, Hamid Techno-Press 2016 Advances in aircraft and spacecraft science Vol.3 No.4

Limit cycle oscillations (LCO) as well as nonlinear aeroelastic analysis of a swept aircraft wing with cubic restoring moments in the pitch degree of freedom is investigated. The unsteady aerodynamic loading applied on the wing is modeled by using the strip theory. The harmonic balance method is used to calculate the LCO frequency and amplitude for the swept wing. Finally the super and subcritical Hopf bifurcation diagrams are plotted. It is concluded that the type of bifurcation and turning point location is sensitive to the system parameters such as wing geometry and sweep angle.

Does maxillomandibular fixation affect skeletal stability following mandibular advancement? A single-blind clinical trial

Reza Tabrizi,Arash Sarrafzadeh,Shervin Shafiei,Hamidreza Moslemi,Ramtin Dastgir 대한악안면성형재건외과학회 2022 Maxillofacial Plastic Reconstructive Surgery Vol.44 No.-

Background: The stability of the results remains a significant concern in orthognathic surgeries. This study aimed to assess the amount of relapse following mandibular advancement with/without maxillomandibular fixation (MMF). Materials and methods: A single-blind clinical trial was conducted on patients with mandibular retrognathism who underwent BSSO for mandibular advancement and Lefort I maxillary superior repositioning. Patients were randomly divided into two groups of treatment (MMF) and control (no MMF). In the treatment group, MMF was performed for 2 weeks; meanwhile, MMF was not performed in the control group, and only guiding elastics were applied postoperatively. Lateral cephalograms were obtained preoperatively (T1), immediately after surgery (T2), and at 1 year postoperatively (T3). The distance from points A and B to the X and Y plane were measured to identify the amount of vertical and horizontal relapse in 1 year as a primary outcome. An independent t-test was applied in order to find differences in outcomes between the control and treatment groups. Results: Fifty-eight patients were evaluated in two groups (28 patients in the MMF group and 30 in the no-MMF group). The magnitude of mandibular advancement following BSSO was 7.68±1.39 mm and 7.53±1.28, respectively, without significant difference among the groups (p= 0.68). The mean sagittal and vertical changes (relapse) at point B were significantly different between the two groups at 1-year follow-up after the osteotomy (p=0.001 and p=0.05, respectively). Conclusion: According to the results of this study, patients with short-term MMF following BSSO for mandibular advancement benefit from significantly greater skeletal stability in the sagittal and vertical dimensions.

On l-Locally Optimum Graph Matching

Cho, Jun-Dong,Kajitani, Yoji,Sarrafzadeh, Majid 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.2

그라프 G=(V,E), |E|=e, |V|=n,에서 최대 매칭수 M은 M에 있는 어느 두 edge가 공통 vertex에 연결되어 있지 않는 최대 edge수를 말한다. 최대 매칭수 M의 정확한 해를 구하는 문제는 O(n^(5/2))의 계산시간을 요구한다. 본 논문에서는 n이 짝수일 때 매칭수의 하한치가 적어도 e/n-1 이상인 결과를 선형 시간 (O(e+n))내에 구하는 대략 알고리듬을 제안한다. 그 결과는 기존의 결과를 향상시킨 결과이며 최악조건에서는 그 하한치가 최적해를 보인다. 본 논문은 제안된 대략 매칭 알고리듬을 MAXCUT에 응용한 결과가 포함되어 있으며 제안된 그라프 대략 매칭 알고리듬은 그밖에 Vertex Cover, Traveling Saleman Problem 및 VLSI 설계 자동화에 적용하여 사용될 수 있다. For a graph G=(V,E) with |E|=e and |V|=n vertices a maximum cardinality matching of G is a subset M of edges with a maximum cardinality such that no two edges of M are incident at a common vertex. The best known algorithm for solving the maximum cardinality matching problem in general graphs requires O(n5/2) time. We propose a maximum cardinality matching algorithm, running in O(e+n) time, yielding the size of matching at least , e/n-1, when n is even. The results improve the bound known before and the derived lowerbounds are existentially tight for the cardinality case. The problem of approximate maximum matching has a number of applications, for example in, MAXCUT, Vertex Cover TSP, and VLSI physical design problems.

Gender-Related Differences in Reliability of Thorax, Lumbar, and Pelvis Kinematics During Gait in Patients With Non-specific Chronic Low Back Pain

Rasool Bagheri,Ismail Ebrahimi Takamjani,Mehdi Dadgoo,Amir Ahmadi,Javad Sarrafzadeh,Mohammad Reza Pourahmadi,Amir-Salar Jafarpisheh 대한재활의학회 2018 Annals of Rehabilitation Medicine Vol.42 No.2

Objective To evaluate test-retest reliability of trunk kinematics relative to the pelvis during gait in two groups (males and females) of patients with non-specific chronic low back pain (NCLBP) using three-dimensional motion capture system. Methods A convenience sample of 40 NCLBP participants (20 males and 20 females) was evaluated in two sessions. Participants were asked to walk with self-selected speed and kinematics of thorax and lumbar spine were captured using a 6-infrared-cameras motion-analyzer system. Peak amplitude of displacement and its measurement errors and minimal detectable change (MDC) were then calculated. Results Intraclass correlation coefficients (ICCs) were relatively constant but small for certain variables (lower lumbar peak flexion in female: inter-session ICC=0.51 and intra-session ICC=0.68; peak extension in male: intersession ICC=0.67 and intra-session ICC=0.66). The measurement error remained constant and standard error of measurement (SEM) difference was large between males (generally ≤4.8°) and females (generally ≤5.3°). Standard deviation (SD) was higher in females. In most segments, females exhibited higher MDCs except for lower lumbar sagittal movements. Conclusion Although ICCs were sufficiently reliable and constant in both genders during gait, there was difference in SEM due to difference in SD between genders caused by different gait disturbance in chronic low back pain. Due to the increasing tendency of measurement error in other areas of men and women, attention is needed when measuring lumbar motion using the method described in this study.