مجله علوم جمهوری اسلامی ایران
سال:1392 | دوره: | شماره: |تعداد مقالات:10

Human serum albumin (HSA) is an abundant, multifunctional and nonglycosylated negatively charged plasma protein. HSA ascribed ligand-binding and transport properties, antioxidant functions and enzymatic activities. In the present study, the interaction and side effects of a new designed anti-cancer compound (1, 10-phenanthroline butyl dithiocarbamato palladium (II) nitrate) on HSA have been investigated by different spectroscopic (UV-visible, fluorescence and circular dichroism (CD)) techniques at two temperatures of 25 and 37oC. By the analysis of fluorescence spectra, it was observed that this complex has an ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The number of binding sites and the association binding constants of Pd (II) complex were calculated at 25 and 37oC. Also, the negative DHo and positive DSo values for the interaction calculated by the vant’s Hoff equation showed that the electrostatic interaction has a major role in the binding process. The quantitative analysis of CD spectra represented that Pd (II) complex induces significantly alterations in the secondary structure of HSAvia decreasing in the content of a helical structure of the protein. Our results suggest that the new synthesized Pd (II) complex can bind to the blood carrier protein of HSA and change the tertiary and secondary structure of the protein, which may be considered as side effects of this new synthesized drug.

Compound action potential (CAP) of spinal cord represents valuable properties of neural fibers including excitability, rate of myelination and membrane integrity. These properties are measured using amplitude, latency and area under curve of CAPs recorded from spinal cord. Here, the isolated spinal cord was set in a double sucrose gap (DSG) chamber and its response to intracellular stimulation was recorded as a CAP signal. Lateral and Dorsal-ventral mechanical presures were then applied on whole spinal cord (WSC) and spinal cord strips (SCS) of isolated spinal cord to mimic spinal cord injury (SCI). In order to identify a representative pattern of CAP applicable in SCI, the recoded CAPs were evaluated, averaged and fitted using Matlab curve fitting toolbox. The results showed a significant decline in the amplitude and conduction velocity (CV) of CAPs caused by SCI in WSC and SCS preparations. This phenomenon was more significant in less myelinated fibers than highly myelinated motoneurons (MNs) and was identified as a decline in the fitted model level. Differential CAPs of WSC and SCS represented mono and biphasic curves that were fitted to Gaussian model levels of "G4" and "G6", respectively. However, the CAP of injured WSC and SCS preparations fitted to Gaussian model level three "G3". Based on the comparative study of WSC and SCS preparations the MN pathways can be traced by recorded CAPs. The current approach can be applied in the identification and evaluation of spinal cord function for experimental and clinical purposes.

1, 8-Dioxo-octahydroxanthene derivatives have efficiently been synthesized from dimedone and aromatic aldehydes using [Fe (III) (salen) Cl] complex as an efficient and homogeneous catalyst in molten tetrabutyl ammonium bromide. This methodology offers several advantages, such as good yields, short reaction times, simple procedure, and mild conditions.

Sepiolite deposits have been recently discovered in northeastern Iran. However, there is still little information about its physicochemical and mineralogical characteristics. Therefore, the collapse of the sepiolite (with sizes of<63 mm) structure induced by temperature elevation in an electric furnace at 350, 550, and 850oC for 4 hours was studied using X-ray diffraction (XRD) in combination with Thermogravimetric analysis (TGA) and infrared spectroscopic analysis. Results showed that the main mineral constituent of the samples is a well crystallized sepiolite. However, dolomite and quartz were also present in minor amounts. Results also revealed that with temperature different phases including ‘sepiolite dihydrite’, ‘sepiolite anhydrite’ and ‘enstatite’ were formed, as magnesium coordinated water and octahedrically coordinated hydroxyl groups, were eliminated and the dehydroxylated phase was recrystallized to enstatite, a stable form of magnesium silicate (MgSiO3).

The Berriasian-Valanginian Fahliyan Formation forms one of the giant reservoirs in the subsurface of the Abadan plain, onshore Iran. A detailed petrographical analysis of the available cores and thin sections revealed that the different diagenetic parameters influenced the reservoir quality of the Fahliyan Formation in this field. The Fahliyan Formation has been influenced by three diagenetic environments, including marine, meteoric and shallow and deep burial environments. The main diagenetic parameters identified in the field under study are dissolution, fracturing, cementation, compaction and dolomitization. Among all, dissolution is the main diagenetic feature improving porosity and reservoir quality. This feature formed as a result of meteoric diagenesis during subearially exposure of the Fahliyan sediments. Fracturing and dolomitization also locally have positive effects on reservoir quality, while compaction, cementation and dolomitization (as cement) have destructive effect on reservoir characteristics.Late stage diagenetic cements such as sparry calcite cement and with lower amount saddle dolomite are the most important and also widespread types of cement decreasing reservoir quality. Based on new genetic classification of porosity, porosity in the Fahliyan Formation are hybrids of three depositional, diagenetic and fracturing, but diagenetic porosity is the most important types of porosity and so Fahliyan reservoir is a type of diagenetic reservoir. Based on this study using petrophysical and petrographical data, the Fahliyan reservoir is not a homogeneous reservoir, so it was divided into eight reservoir zones with different specifications.

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Let X be a random variable from a normal distribution with unknown mean q and known variance  s2. In many practical situations, q is known in advance to lie in an interval, say [- m, m], for some m>0. As the usual estimator of q, i.e., X under the LINEX loss function is inadmissible, finding some competitors for X becomes worthwhile. The only study in the literature considered the problem of minimax estimation of q In this paper, by constructing a dominating class of estimators, we show that the maximum likelihood estimator is inadmissible. Then, as a competitor, the Bayes estimator associated with a uniform prior on the interval [- m, m] is proposed. Finally, considering risk performance as a comparison criterion, the estimators are compared and depending on the values taken by q in the interval [- m, m], the appropriate estimator is suggested.

Let A be a Banach algebra. Let  d, e be linear mappings on A. First we demonstrate a theorem concerning the continuity of double derivations; especially that all of (d, e) -double derivations are continuous on semi-simple Banach algebras, in certain case. Afterwards we define a new vocabulary called “(d, e) - higher double derivation" and present a relation between this subject and derivations and finally give some theorems and corollaries about the automatic continuity of this notion.

Spatial-temporal modeling of air pollutants, ground-level ozone concentrations in particular, has attracted recent attention because by using spatial-temporal modeling, can analyze, interpolate or predict ozone levels at any location. In this paper we consider daily averages of troposphere ozone over Tehran city. For eliminating the trend of data, a dynamic linear model is used, then some features of correlation structure of de-trended data, such as stationarity, symmetry and separability are considered. Next based on the obtained features, an appropriate model is proposed. This model can be used for future predictions of ozone in Tehran.

The time evaluation of quantum entropy in a four-level double- L type atomic system is theoretically investigated. Quantum entanglement of the atom and its spontaneous emission fields is then discussed via quantum entropy. It is found that the degree of entanglement can be increased by the quantum interference induced by spontaneous emission. The phase dependence of the atom-field entanglement is also presented.