Comparative Kinetic Studies of Two Staphylococcal Lipases Using the Monomolecular Film Technique

Sayari, Adel,Verger, Rebert,Gargourl, Youssef 생화학분자생물학회 1990 BMB Reports Vol.34 No.5

Using the monomolecular film technique, we compared the interfacial properties of Staphylococcus simulans lipase (SSL) and Staphylococcus aureus lipase (SAL). These two enzymes act specifically on glycerides without any detectable phospholipase activity when using various phospholipids. Our results show that the maximum rate of racemic dicaprin (rac-dicaprin) hydrolysis was displayed at pH 8.5, or 6.5 with Staphylococcus simulans lipase or Staphylococcus aureus lipase, respectively The two enzymes interact strongly with egg-phosphatidyl choline (egg-PC) monomolecular films, evidenced by a critical surface pressure value of around 23 mN·m^(-1). In contrast to pancreatic lipases, β-lactoglobulin, a tensioactive protein, failed to inhibit Staphylococcus simulans lipase and Staphylococcus aureus lipase. A kinetic study on the surface pressure dependency, stereoselectivity, and regioselectivity of Staphylococcus simulans lipase and Staphylococcus aureus lipase was performed using optically pure stereoisomers of diglycerides (1,2-sndicaprin and 2,3-sn-dicaprin) and a prochiral isomer (1,3-sn-dicaprin) that were spread as monomolecular films at the air-water interface. Both staphylococcal lipases acted preferentially on distal carbo7cylic ester groups of the diglyceride isomer (1,3-sn-dicaprin). Furthermore, Staphylococcus simulans lipase was found to be markedly stereoselective for the sn-3 position of the 2,3-sn-dicaprin isomer.

Toroidal Manifolds and Dehn Fillings on Links

Sayari, Nabil Department of Mathematics 2007 Kyungpook mathematical journal Vol.47 No.3

Let M be a hyperbolic 3-manifold such that ${\partial}M$ has at least two boundary tori ${\partial}_oM$ and ${\partial}_1M$. Suppose that M contains an essential orientable surface P of genus $g$ with one outer boundary component ${\partial}_oP$, lying in ${\partial}_oM$ and having slope ${\lambda}$ in ${\partial}_oM$, and $p$ inner boundary components ${\partial}_iP$, $i=1$, ${\cdots}$, $p$, each having slope ${\alpha}$ in ${\partial}_1M$. Let ${\beta}$ be a slope in ${\partial}_1M$ and suppose that $M({\beta})$ is toroidal. Let $\hat{T}$ be a minimal essential torus in $M({\beta})$, which means that $\hat{T}$ is pierced a minimal number of times by the core of the ${\beta}$-Dehn filling, among all essential tori in $M({\beta})$. Let $T=\hat{T}{\cap}M$ and denote by $t$ the number of components of ${\partial}T$. In this paper we prove: (i) if $t{\geq}3$, then ${\Delta}({\alpha},{\beta}){\leq}6+\frac{10g-5}{p}$, (ii) If $t=2$, then ${\Delta}({\alpha},{\beta}){\leq}13+\frac{24g-12}{p}$, (iii) If $t=1$, then ${\Delta}({\alpha},{\beta}){\leq}1$.

Comparative Kinetic Studies of Two Staphylococcal Lipases Using the Monomolecular Film Technique

Sayari, Adel,Verger, Robert,Gargouri, Youssef Korean Society for Biochemistry and Molecular Biol 2001 Journal of biochemistry and molecular biology Vol.34 No.5

Using the monomolecular film technique, we compared the interfacial properties of Staphylococcus simulans lipase (SSL) and Staphylococcus aureus lipase (SAL). These two enzymes act specifically on glycerides without any detectable phospholipase activity when using various phospholipids. Our results show that the maximum rate of racemic dicaprin (rac-dicaprin) hydrolysis was displayed at pH 8.5, or 6.5 with Staphylococcus simulans lipase or Staphylococcus aureus lipase, respectively The two enzymes interact strongly with egg-phosphatidyl choline (egg-PC) monomolecular films, evidenced by a critical surface pressure value of around $23\;mN{\cdot}m^{-1}$. In contrast to pancreatic lipases, $\beta$-lactoglobulin, a tensioactive protein, failed to inhibit Staphylococcus simulans lipase and Staphylococcus aureus lipase. A kinetic study on the surface pressure dependency, stereoselectivity, and regioselectivity of Staphylococcus simulans lipase and Staphylococcus aureus lipase was performed using optically pure stereoisomers of diglycerides (1,2-sn-dicaprin and 2,3-sn-dicaprin) and a prochiral isomer (1,3-sn-dicaprin) that were spread as monomolecular films at the air-water interface. Both staphylococcal lipases acted preferentially on distal carboxylic ester groups of the diglyceride isomer (1,3-sn-dicaprin). Furthermore, Staphylococcus simulans lipase was found to be markedly stereoselective for the sn-3 position of the 2,3-sn-dicaprin isomer.

The relationship between subclinical hypothyroidism and serum levels of uric acid and creatinine in children aged 2–14 years

Saba Sayari,Ziba Molaei,Zohre Torabi 대한소아내분비학회 2018 Annals of Pediatirc Endocrinology & Metabolism Vol.23 No.1

Purpose: Hypothyroidism is a clinical syndrome that can lead to elevated levels of serum creatinine and uric acid by causing impaired renal function. Although many studies have been carried out on the relationship between overt hypothyroidism and renal function, few studies have been conducted on subclinical hypothyroidism and renal function, especially in pediatric patients. For this reason, we studied this issue in children, so as to provide a background for more useful research and future education. Methods: This case-control study was performed on 107 children aged 2–14 years, 56 children with subclinical hypothyroidism in the case group, and 51 healthy children in the control group presenting to Ayatollah Mousavi Hospital in Zanjan and private clinics of Zanjan city. Thyroid stimulating hormone, triiodothyronine, thyroxine, creatinine, and uric acid were measured in both groups of children after obtaining the necessary criteria for entering the study. Results: Compared to the control group, subjects with subclinical hypothyroidism had higher levels of creatinine (P=0.003), while serum uric acid levels in subclinical hypothyroid children was not significantly different from those in the control group (P=0.200). Conclusion: In subclinical hypothyroidism in children, creatinine was higher than in euthyroid patients, but uric acid was not different.

Combined effects of synbiotic and sitagliptin versus sitagliptin alone in patients with nonalcoholic fatty liver disease

( Saba Sayari ),( Hassan Neishaboori ),( Maryam Jameshorani ) 대한간학회 2018 Clinical and Molecular Hepatology(대한간학회지) Vol.24 No.3

Background/Aims: Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver diseases in recent years. The aim of this study was to evaluate the effects of sitagliptin with and without a synbiotic supplement in the treatment of patients with NAFLD. Methods: In total, 138 NAFLD patients aged 18-60 years were enrolled in the study. Patients were randomized to one of the following treatments for 16 weeks: Group I (n=68), sitagliptin 50 mg daily plus placebo (one capsule per day) or group II (n=70) sitagliptin 50 mg daily plus synbiotic (one capsule per day). Changes in fasting blood glucose (FBS), liver enzymes, lipid profile, and body mass index were compared between the groups. Results: The mean change in FBS with sitagliptin-placebo from baseline was -10.47±5.77 mg/dL, and that with sitagliptin-synbiotic was -13.52±4.16 mg/dL. There was a significant difference between the groups (P<0.001). The mean change in cholesterol (Chol) was -8.34±28.83 mg/dL with sitagliptin-placebo and -21.25±15.50 mg/dL with sitagliptinsynbiotic. There was a significant difference between the two groups (P=0.029). The administration of sitagliptin-placebo induced an increase of 6.13±27.04 mg/dL in low density lipoprotein (LDL), whereas sitagliptin-synbiotic induced a decrease of 14.92±15.85 mg/dL in LDL. A significant difference was observed between the two groups (P<0.001). On the other hand, in the sitagliptin-synbiotic group, there was significant improvement in aspartate aminotransferase (AST) level compared to the sitagliptin-placebo group (P=0.018). Conclusions: Sitagliptin-synbiotic produced greater improvement in FBS, AST, Chol, and LDL compared to sitagliptin alone in patients with NAFLD. (Clin Mol Hepatol 2018;24:331-338)

Klein Bottles and Dehn Filling on a Component of Twocomponent Link Exterior

Nabil Sayari 경북대학교 자연과학대학 수학과 2020 Kyungpook mathematical journal Vol.60 No.4

Let M be the exterior of a hyperbolic link K ∪ L in a homology 3-sphere Y , such that the linking number lk(K, L) is non-zero. In this note we prove that if γ is a slope in ∂N(L) such that the manifold ML(γ) obtained by γ-Dehn filling along ∂N(L) contains a Klein bottle, then there is a bound on ∆(µ, γ), depending on the genus of K and on lk(K, L).

Personal Health of Spine Surgeons Can Impact Perceptions, Decision-Making and Healthcare Delivery During the COVID-19 Pandemic - A Worldwide Study

Arash J. Sayari,Garrett K. Harada,Philip K. Louie,Michael H. McCarthy,Michael T. Nolte,Gary M. Mallow,Zakariah Siyaji,Niccole Germscheid,Jason P.Y. Cheung,Marko H. Neva,Mohammad El-Sharkawi,Marcelo Va 대한척추신경외과학회 2020 Neurospine Vol.17 No.2

Objective: To determine if personal health of spine surgeons worldwide influences perceptions, healthcare delivery, and decision-making during the coronavirus disease 2019 (COVID-19) pandemic. Methods: A cross-sectional study was performed by distributing a multidimensional survey to spine surgeons worldwide. Questions addressed demographics, impacts and perceptions of COVID-19, and the presence of surgeon comorbidities, which included cancer, cardiac disease, diabetes, obesity, hypertension, respiratory illness, renal disease, and current tobacco use. Multivariate analysis was performed to identify specific comorbidities that influenced various impact measures. Results: Across 7 global regions, 36.8% out of 902 respondents reported a comorbidity, of which hypertension (21.9%) and obesity (15.6%) were the most common. Multivariate analysis noted tobacco users were more likely to continue performing elective surgery during the pandemic (odds ratio [OR], 2.62; 95% confidence interval [CI], 1.46–4.72; p = 0.001) and were less likely to utilize telecommunication (OR, 0.51; 95% CI, 0.31–0.86; p = 0.011), whereas those with hypertension were less likely to warn their patients should the surgeon become infected with COVID-19 (OR, 0.57; 95% CI, 0.37–0.91; p = 0.017). Clinicians with multiple comorbidities were more likely to cite personal health as a current stressor (OR, 1.32; 95% CI, 1.07–1.63; p = 0.009) and perceived their hospital’s management unfavorably (OR, 0.74; 95% CI, 0.60–0.91; p = 0.005). Conclusion: This is the first study to have mapped global variations of personal health of spine surgeons, key in the development for future wellness and patient management initiatives. This study underscored that spine surgeons worldwide are not immune to comorbidities, and their personal health influences various perceptions, healthcare delivery, and decision-making during the COVID-19 pandemic.

Perfect tracking of ZMP trajectory for humanoid locomotion using repetitive control

Mohamed A. Sayari,Riadh Zaier,Neila Masmoudi 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.12

In this paper, the tracking of the zero moment point (ZMP) trajectory for humanoid locomotion is addressed. For that, a combination of a repetitive controller (RC) and a linear quadratic regulator (LQR) is proposed. The RC controller achieves a zero steady state tracking error for any periodic desired output with a fixed period. Here, the robot model is simplified as a cart table model. In the first stage, a walking pattern with constant gait is considered to allow the use of a repetitive controller. The results are then compared to a classical PD control. In the second part, the proposed controller is applied to track a desired ZMP profile generated using a central pattern generator (CPG). Here, the speed of the oscillator is adjusted via a proper selection of the parameters of the CPG and the RC design is simultaneously updated to assure the perfect tracking of the ZMP.

Mathematical analysis of an ``SIR'' epidemic model in a continuous reactor - deterministic and probabilistic approaches

Miled El Hajji,Sayed Sayari,Abdelhamid Zaghdani 대한수학회 2021 대한수학회지 Vol.58 No.1

In this paper, a mathematical dynamical system involving both deterministic (with or without delay) and stochastic ``SIR'' epidemic model with nonlinear incidence rate in a continuous reactor is considered. A profound qualitative analysis is given. It is proved that, for both deterministic models, if $\R_d > 1$, then the endemic equilibrium is globally asymptotically stable. However, if $\R_d \leq 1$, then the disease-free equilibrium is globally asymptotically stable. Concerning the stochastic model, the Feller's test combined with the canonical probability method were used in order to conclude on the long-time dynamics of the stochastic model. The results improve and extend the results obtained for the deterministic model in its both forms. It is proved that if $\R_s > 1$, the disease is stochastically permanent with full probability. However, if $\R_s \leq 1$, then the disease dies out with full probability. Finally, some numerical tests are done in order to validate the obtained results.

Evaluation of mathematical models for prediction of slump, compressive strength and durability of concrete with limestone powder

Bazrafkan, Aryan,Habibi, Alireza,Sayari, Arash Techno-Press 2020 Advances in concrete construction Vol.10 No.6

Multiple mathematical modeling for prediction of slump, compressive strength and depth of water penetration at 28 days were performed using statistical analysis for the concrete containing waste limestone powder as partial replacement of sand obtained from experimental program reported in this research. To extract experimental data, 180 concrete cubic samples with 20 different mix designs were investigated. The twenty non-linear regression models were used to predict each of the concrete properties including slump, compressive strength and water depth penetration of concrete with waste limestone powder. Evaluation of the models using numerical methods showed that the majority of models give acceptable prediction with a high accuracy and trivial error rates. The 15-term regression models for predicting the slump, compressive strength and water depth were found to have the best agreement with the tested concrete specimens.