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Latifi, Reza,Tahsini, Laleh,Kumar, Devesh,Sastry, G. Narahari,Nam, Wonwoo,de Visser, Sam P. Royal Society of Chemistry 2011 Chemical communications Vol.47 No.38
<P>Density functional theory calculations on the reactivity of a Ni(<SMALL>II</SMALL>)-superoxo complex in C–H bond activation, aromatic hydroxylation and heteroatom oxidation reactions have been explored; the Ni(<SMALL>II</SMALL>)-superoxo complex is able to react with substrates with weak C–H bonds and PPh<SUB>3</SUB>.</P> <P>Graphic Abstract</P><P>Density functional theory calculations on the reactivity of a Ni(<SMALL>II</SMALL>)-superoxo complex in C–H bond activation, aromatic hydroxylation and heteroatom oxidation reactions have been explored. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c1cc13993b'> </P>
Latifi, Reza,Tahsini, Laleh,Nam, Wonwoo,de Visser, Sam P. The Royal Society of Chemistry 2012 Physical chemistry chemical physics Vol.14 No.7
<P>Many enzymes in nature utilize molecular oxygen on an iron center for the catalysis of substrate hydroxylation. In recent years, great progress has been made in understanding the function and properties of iron(<SMALL>IV</SMALL>)-oxo complexes; however, little is known about the reactivity of iron(<SMALL>II</SMALL>)-superoxo intermediates in substrate activation. It has been proposed recently that iron(<SMALL>II</SMALL>)-superoxo intermediates take part as hydrogen abstraction species in the catalytic cycles of nonheme iron enzymes. To gain insight into oxygen atom transfer reactions by the nonheme iron(<SMALL>II</SMALL>)-superoxo species, we performed a density functional theory study on the aliphatic and aromatic hydroxylation reactions using a biomimetic model complex. The calculations show that nonheme iron(<SMALL>II</SMALL>)-superoxo complexes can be considered as effective oxidants in hydrogen atom abstraction reactions, for which we find a low barrier of 14.7 kcal mol<SUP>−1</SUP> on the sextet spin state surface. On the other hand, electrophilic reactions, such as aromatic hydroxylation, encounter much higher (>20 kcal mol<SUP>−1</SUP>) barrier heights and therefore are unlikely to proceed. A thermodynamic analysis puts our barrier heights into a larger context of previous studies using nonheme iron(<SMALL>IV</SMALL>)-oxo oxidants and predicts the activity of enzymatic iron(<SMALL>II</SMALL>)-superoxo intermediates.</P> <P>Graphic Abstract</P><P>Calculations show that iron(<SMALL>II</SMALL>)-superoxo is a possible oxidant in hydrogen abstraction reactions but not in aromatic hydroxylation reactions. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp23352e'> </P>
Latifi, Reza,Valentine, Joan S.,Nam, Wonwoo,de Visser, Sam P. The Royal Society of Chemistry 2012 Chemical communications Vol.48 No.29
<P>Density functional theory calculations compare the reactivity of iron(<SMALL>IV</SMALL>)–oxo porphyrin and corrole cation radical species in H-atom abstraction reactions.</P> <P>Graphic Abstract</P><P>We compare the hydrogen abstraction ability of iron(<SMALL>IV</SMALL>)–oxo porphyrin <I>versus</I> iron(<SMALL>IV</SMALL>)–oxo corrole with a selection of substrates. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cc30365e'> </P>
High temperature water gas shift reaction over Fe-Cr-Cu nanocatalyst fabricated by a novel method
Seyed Mahdi Latifi,Alireza Salehirad 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2
Fe-Cr-Cu nanocatalyst was synthesized through an inorganic-precursor thermolysis approach and exploited for high temperature water gas shift reaction. The results demonstrated that the method used for the nanocatalyst fabrication led to smaller crystallite size (32.9 nm) and higher BET surface area (127.3m2/g) compared to those of a reference sample (65.5 nm, 78.6m2/g) prepared by co-precipitation conventional method. Furthermore, the obtained data for catalytic activity showed that the catalyst prepared via inorganic precursor has better activity than the reference sample in all studied temperatures (350-500 oC) and also exhibited higher catalytic activity than a commercial Fe-Cr- Cu catalyst in higher temperatures (more than 450 oC).
Fereydoun Pourdanesh,Noorahmad Latifi,Fatemeh Latifi 대한구강악안면외과학회 2018 대한구강악안면외과학회지 Vol.44 No.5
Among different graft materials for craniofacial reconstruction, calcium phosphate cements have the advantages of alloplastic grafts and wide use. The authors report a case of foreign body reaction following frontal reconstruction with JectOS (an injectable calcium orthophosphate cement; Kasios) and reviewed the literature on complications of this material after craniofacial reconstruction from 2002 to 2017. Complications were categorized into two groups: immunologic reactions (consisting of seroma collection, chronic sinus mucosa swelling, and foreign body reaction) and non-immune events (infection, fragmentation, and ejection). It is wise to use calcium phosphate-based material only in selected cases with small defects, and long-term follow-up is needed to observe their consequences.
Raei, Negin,Latifi-Navid, Saeid,Zahri, Saber Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.15
Background: Gastric cancer (GC) is the third most common cancer regarding mortality in the world. The cag pathogenicity island (PAI) of Helicobacter pylori which contains genes associated with a more aggressive phenotype may involve in the pathogenesis of gastrointestinal disease. We here aimed to examine the associations of cagH, cagL, orf17, and cagG genotypes of H. pylori cag PAI with severe gastrointestinal disease. Materials and Methods: A total of 242 H. pylori strains were genotyped. Histopathological examination and classification of subjects were performed. Results: The frequencies of the cagH, cagL, cagG, and orf17 genotypes were 40/54 (74.1%), 53/54 (98.1%), 38/54 (70.4%), and 43/54 (79.6%), respectively, in patients with peptidic ulceration (PU),while in the control group, the frequencies were 87/147 (59.6%) for cagH, 121/146 (82.9%) for cagL, 109/146 (74.7%) for cagG, and 89/146 (61.0%) for orf17. The results of simple logistic regression analysis showed that the cagL and orf17 genotypes were significantly associated with an increased risk of PU not GC; the ORs (95% CI) were 10.950 (1.446-82.935), and 2.504 (1.193-5.253), respectively. No significant association was found between the cagH and cagG genotypes and the risk of both the PU and the GC in Iran (P>0.05). Finally, multiple logistic regression analysis showed that the cagL genotype was independently and significantly associated with the age-and sex-adjusted risk for PU; the OR (95% CI) was 9.557 (1.219-17.185). Conclusions: We conclude that the orf17 and especially cagL genotypes of H. pylori cag PAI could be factors for risk prediction of PU, but not GC in Iran.
Abdi, Esmat,Latifi-Navid, Saeid,Yazdanbod, Abbas,Zahri, Saber Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.2
Background: Ardabil, a Northwestern province of Iran, was found to have the highest rate of gastric cancer (GC) in the country (ASRs = 51.8/100,000 for males and 24.9/100,000 for females) and one of the highest gastric cardia cancer rates in the world. The aim of the present study was to assess the associations of the cagA and babA2 status of Helicobacter pylori with GC in the Ardabil population. Materials and Methods: A total of 103 patients with non-atrophic gastritis (56) and GC (47), who underwent endoscopy at the Imam Khomeini Hospital in Ardabil, were assessed. The status of 16S rDNA, cagA and babA2 genes was determined using PCR and histopathological assessment was performed. Results: The following genotypic frequency was observed: cagA+ (50.6%), cagA-(49.4%), babA2+ (26.5%), babA2- (73.5%) cagA+/babA2+ (19.3%), cagA-/babA2+ (7.2%), cagA+/babA2-(31.3%), cagA-/babA2-(42.2%). Although the frequency of the cagA+, cagA+/babA2+ and cagA-/babA2+ genotypes in patients with GC (55.6%, 25.9%, and 14.8%, respectively) was higher than in those with NAG (48.2%, 16.1%, and 3.6%, respectively), the difference did not reach significance. In contrast, the presence of the babA2 gene (40.7% vs 19.6%) significantly increased the risk of GC; the age-sex-adjusted odds ratio (95% confidence interval) was 5.068 (1.506-17.058; P=0.009), by multiple logistic regression. Conclusions: It is proposed that the H. pylori babA2 positivity might be considered as an important determinant of GC risk in Ardabil.
Rassam, Ghorbanali,Latifi, Nasser,Soltani, Afshin,Kamkar, Behnam The Korean Society of Weed Science and The Turfgra 2011 Weed Biology and Management Vol.11 No.2
The aim of this study was to assess the effects of crop management practices on the diversity, structure, and composition of weed communities. A total of 30 fields (15 fields each) in low-input and conventional farming systems were surveyed in north-eastern Iran. In the conventional cropping system, both mineral fertilizers and herbicides were applied, while in the low-input cropping system, the fertilizer was mainly manure and herbicides were avoided. The results showed that the pool of species, species richness, number of unique species, and Shannon's diversity index were greater in the low-input system than in the conventional system. Both cropping systems had more broad-leaved species than grasses and more annual species than perennial species. All the multivariate methods of analysis that were applied revealed that the weed community composition was significantly different between the two management types. The low-input cropping favored herbicide-susceptible broad-leaved weeds, legumes, and weeds with biodiversity value, whereas a high proportion of herbicide-tolerant grasses was found in the conventional fields. The results suggest that low-input cropping can sustain high weed diversity and abundance.
Numerical study of progressive collapse in reinforced concrete frames with FRP under column removal
Esfandiari, J.,Latifi, M.K. Techno-Press 2019 Advances in concrete construction Vol.8 No.3
Progressive collapse is one of the factors which if not predicted at the time of structure plan; its occurrence will lead to catastrophic damages. Through having a glance over important structures chronicles in the world, we will notice that the reason of their collapse is a minor damage in structure caused by an accident like a terrorist attack, smashing a vehicle, fire, gas explosion, construction flaws and its expanding. Progressive collapse includes expanding rudimentary rupture from one part to another which leads to total collapse of a structure or a major part it. This study examines the progressive collapse of a 5-story concrete building with three column eliminating scenarios, including the removal of the corner, side and middle columns with the ABAQUS software. Then the beams and the bottom of the concrete slab were reinforced by (reinforcement of carbon fiber reinforced polymer) FRP and then the structure was re-analyzed. The results of the analysis show that the reinforcement of carbon fiber reinforced polymer sheets is one of the effective ways to rehabilitate and reduce the progressive collapse in concrete structures.