• Journal of Environmental Science International
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• v.7 no.1
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• pp.104-111
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• 1998

The Dongbok lake water before and after alum coagulation and activated carbon adsorption were analyzed in terms of organic contents, molecular weight distributuin (MWD), and UV-absorbance. Dissolved organic compounds in the Dongbok lake were fractionated into three molecular size classes by gel permeation chromatography. The fractionation was reasonably successful in isolating compounds with The bulk of the dissolved carbon was present in compounds of molecular weight in the range of 3,000~10,000. Alum coagulation preferentially treated molecules of high molecular weight, which has molecules larger than 10,000. The dissolved organic carbon (DOC) removal after activated carbon adsorption was high in the Fraction B , IR . The $A_{260}$/DOC ratio after alum and activated carbon treatment the Fraction II, III. This results suggest that the organics remaining after each treatment has a trihalomethane formation potential

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.68-75
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• 1993

Various biological activities (enzyme inhibitory potency, lipoxygenase inhibition, tadpole narcosis, vapor toxicity and heat of vaporization) of molecules are correlated with molecular descriptors. The molecular descriptors used in this works are molecular connectivity index, Wiener distance index and ad hoc descriptor, which can encode information about branching, size, cyclization, unsaturation, hetero atom content and polarizability. It is found that calculated values from multiple regression equations are in a good agreement with experimental data on five biological activities of alcohol, ester and ketone compounds.

• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.106-112
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• 1994

Six physical properties (molecular weight, heat capacity, side chain weight, side chain volume, standard entropy and partial molar volume) of amino acids, peptides and their derivatives were examined by molecular modeling techniques. The molecular connectivity index, Wiener distance index and ad hoc descriptor are employed as structural parameters to encode information about branching, size, cyclization, unsaturation, heteroatom content and polarizability. This paper examines the correlation of the molecular modeling techique's parameters and the physicochemical properties of amino acids and their derivatives. As a result, calculated values were in agreement with experimental data in the above six physical properties of amino acids, peptides and their derivatives and the molecular connectivity index was superior to the other indices in fitting the calculated data.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.4 no.2
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• pp.115-120
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• 2018

In recent years, many researchers have attempted to make use of 2D nanoparticles as molecular imaging probes since extensive investigations proved that 2D nanoparticles in the body tends to accumulate certain lesions by enhanced permeability and retention (EPR) effect. For example, graphene and carbon nitride which have high surface area and modifiable properties showed good biocompatibility and targetability when it used as imaging probes. However, poor dispersibility in physiological mediums and its uncontrolled size limited its usage in bio-application. Therefore, oxidation process and mechanical exfoliation have been developed for overcoming these problems. In this paper, we highlight the several major methods to synthesize biocompatible 2D nanomaterials like graphene and carbon nitride especially for molecular imaging study including positron emission tomography (PET).

• Analytical Science and Technology
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• v.15 no.4
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• pp.373-380
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• 2002

Humic and fulvic acids present in soil of different depth were extracted and their characteristics were analyzed as a basic study to evaluate the effect of humic substances on the behaviour of radioactive elements deposited on soil. Molecular size distribution of the humic and fulvic acids was measured by stirred cell ultrafiltration technique and the structural informations were obtained from their UV-Vis., IR and synchronous fluorescence (SyF) spectral analysis. Main molecular size ranges of the soil 1) humic and fulvic acids were 30~100 kDa (46~56%) and 10~30 kDa (33~43%) respectively, and their overall molecular sizes were found to became smaller with increasing the soil depth. Absorptivities measured at 280 nm in the UV-Visible spectra of humic acids were 1.4~1.5 times higher than those of fulvic acids, and increased with increasing the soil depth. SyF spectral data showed two distinct peak components having maximum peak positions of 428 nm (type I) and 498 nm (type II) for the soil humic and fulvic acids. From the analysis of the peak components, it was found that humic molecules are mainly made up of aromatic compounds corresponding to longer wavelength (type II), and the molecular components increased with increasing the soil depth. Analysis of IR spectral data indicated that the humic molecules contain a higher relative concentration of carboxylic groups than those of fulvic molecules, and the carboxylic group contents are seen to increase as the soil depth increase.

• Polymer(Korea)
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• v.26 no.3
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• pp.307-315
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• 2002

Major factors affecting the impact resistance of high impact polystyrene (HIPS), the rubber-toughened grade of polystyrene, are rubber-phase particle size and size distribution, molecular weight, morphology, and degree of grafting. Accordingly, it is important to control or investigate these factors. In this study, the effect of solvent content was analyzed by the morphology and particle size distribution of rubber phase, and final properties in bulk-solution polymerization of HIPS. The prepolymerization time was, first, determined by measuring the evolution of particle size distribution of dispersed phase to explain the phase inversion with time. As the solvent content increased, the size of rubber particle increased and then gradually decreased. Rubber-phase morphology was likely to have higher degree of grafting as the solvent content increased. Rheological and mechanical properties decreased as the solvent content increased because of the decrease of matrix molecular weight due to the chain transfer reaction to solvent and the existence of residual solvent. Nevertheless, the impact resistance seemed to increase when the rubber particle size increased.

• Analytical Science and Technology
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• v.14 no.2
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• pp.159-166
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• 2001

A humic acid(HA, Aldrich Co) sample was subjected to ultrafiltration for molecular size fractionation and three fractions of different nominal size($F_1$: 1,000-10,000 daltons; $F_2$: 10,000-50,000 daltons; $F_3$: 100,000-300,000 daltons) were obtained. The structural characteristics of the size-fractionated HA were analyzed using their IR and solid state C-13 NMR spectral data, and the carboxylate group contents of the humic acids were determined using their pH titration data. The $^7F_0-{^5}D_0$ excitation spectra of Eu(III) complexes of the size-fractionated mgHA in aqueous solution were acquired($[Eu(III)]=1.0{\times}10^{-4}mol\;L^{-1}$, $(HA)=470-970mg\;L^{-1}$) at pH 5.0 using a pulsed tunable laser system, in which metal binding properties of the size-fractionated HA were elucidated and compared on another. Characterization of the IR and C-13 NMR spectral data indicated that the fraction($F_3$) with molecules of larger size were primarily aliphatic, while the fractions($F_1$, $F_2$) with smaller molecules of less than 50,000 daltons were predominantly aromatic. Titration data were consistent with an increase in the number of carboxylate groups per unit mass as molecular size became smaller. The $^7F_0-{^5}D_0$ excitation spectral data of Eu(III)-humate complexes showed that the peak maxima on these spectra were shifted toward lower energies with increasing molecular size of HA, indicating the higher degree of bindings of the Eu in the molecules of larger size. We also discussed the relationship of the lower energy shifts of the maximum peaks with increasing the molecular size of HA with the structural differences of the size-fractionated HA.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8057-8062
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• 2014

Purpose: The aim of the study was to evaluate the correlation of ultrasound features with breast cancer molecular status. Materials and Methods: A retrospective review was performed of ultrasound findings in 263 patients diagnosed with breast invasive ductal carcinoma for comparison with immunohistochemistric results were obtained from each lesion. Relationships between ultrasound findings and molecular status were investigated by using multiple regression analysis by means of stepwise logistic regression. Differences in ultrasound criteria were assessed among women with different molecular status. Results: ER positivity was associated with small size, lobulate, angular or spiculated margin contours, absence of calcification, posterior tumor shadowing and low elasticity score; PR positivity was associated with small size, lobulate or angular or spiculated margin contours and absence of calcification; HER2 positivity was associated with presence of calcification and absence of any echogenic halo. The calculated models of predicted molecular status were accurate and discriminating with AUCs of 0.78, 0.74, and 0.74, respectively. Conclusions: Breast cnacer ultrasound features show some correlation with the molecular status. These models may help to expand the scope of ultrasound in predicting tumor biology.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.911-915
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• 2013

The aim of this study was to investigate allele frequencies at the CSN1S2 locus in two Chinese dairy goat breeds and the effects of its variation on dairy goat economic traits. Seven hundred and eight goats from Xinong Saanen (XS, n = 268) and Guanzhong (GZ, N = 440) breeds were selected. The milk samples of 268 XS goats were collected during the middle of lactation, body size parameters (708 goats) and daily milk yield (202 goats) were registered. The RFLP (restriction fragment length polymorphism) and SSCP (single strand conformation polymorphism) were used to detect the polymorphisms in CSN1S2. The Hardy-Weinberg (HW) equilibrium and the associations between body size, milk yield and composition and the genotypes were calculated. The results revealed that only A and F CSN1S2 alleles were found in the two Chinese dairy goat breeds. Allelic frequencies of A and F were 0.795, 0.205 and 0.739, 0.261 in Xinong Saanen and Guanzhong population respectively. Xinong Saanen breed was in Hardy-Weinberg equilibrium, while Guanzhong breed deviated from Hardy-Weinberg equilibrium (p<0.05). The association of polymorphism with economic traits indicated that the goats with FF genotype have higher milk fat and total solid concentration than those with AA and AF genotypes (p<0.05).

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.1881-1886
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• 2012

Breast cancer is a heterogeneous disease that is affected by ethnicity of patients. According to hormone receptor status and gene expression profiling, breast cancers are classified into four molecular subtypes, each showing distinct clinical behavior. Lack of sufficient data on molecular subtypes of breast cancer in Iran, prompted us to investigate the prevalence and the clinicopathological features of each subtype among Iranian women. A total of 428 women diagnosed with breast cancer from 2002 to 2011 were included and categorized into four molecular subtypes using immunohistochemistry. Prevalence of each subtype and its association with patients' demographics and tumor characteristics, such as size, grade, lymph-node involvement and vascular invasion, were investigated using Chi-square, analysis of variance and multivariate logistic regression. Luminal A was the most common molecular subtype (63.8%) followed by Luminal B (8.4%), basal-like (15.9%) and HER-2 (11.9%). Basal-like and HER-2 subtypes were mostly of higher grades while luminal A tumors were more of grade 1 (P<0.001). Vascular invasion was more prevalent in HER-2 subtype, and HER-2 positive tumors were significantly associated with vascular invasion (P=0.013). Using muti-variate analysis, tumor size greater than 5 cm and vascular invasion were significant predictors of 3 or more nodal metastases. Breast cancer was most commonly diagnosed in women around 50 years of age and the majority of patients had lymph node metastasis at the time of diagnosis. This points to the necessity for devising an efficient screening program for breast cancer in Iran. Further, prospective surveys are suggested to evaluate prognosis of different subtypes in Iranian patients.