Влияние пластификации на тепловое расширение полимеров

В статье рассмотрено влияние пластификации и модификации некоторых полимеров на температуру стеклования и параметры теплового расширения. В термопластичных полимерах, с достаточно гибкими макромолекулярными цепями, введение пластификатора или модификатора не влияет на величину свободного объема при Т=ТС и поведение таких систем подчиняется эмпирическому правилу Симха и Бойера. Отклонения от него наблюдаются лишь при больших концентрациях пластификатора, ограниченно совмещающегося с полимером

Designing rigid carbon foams

We use ab initio density functional calculations to study the stability, elastic properties and electronic structure of sp2 carbon minimal surfaces with negative Gaussian curvature, called schwarzites. We focus on two systems with cubic unit cells containing 152 and 200 carbon atoms, which are metallic and very rigid. The porous schwarzite structure allows for efficient and reversible doping by electron donors and acceptors, making it a promising candidate for the next generation of alkali ion batteries. We identify schwarzite structures that act as arrays of interconnected quantum spin dots or become magnetic when doped. We introduce two interpenetrating schwarzite structures that may find their use as the ultimate super-capacitor.Comment: 6 pages, 5 figure

Evaluation for Damaged Degree of Vegetation by Forest Fire Using LiDAR and Digital Aerial Photograph

The amount of vegetation physically damaged by forest fire can be evaluated using lidar (Light Detection And Ranging) data because the loss of canopy height and width by forest fire can be relevant to the number of points transmitted to the ground through the canopy of the damaged forest. On the other hand, the biological damage of vegetation caused by forest fire can be obtained from the Normalized Difference Vegetation Index (NDVI), which determines the vegetation vitality. In this study, the degree of physical damage from the lidar data was classified into serious physical damage (SPD) and light physical damage (LPD). The degree of biological damage using NDVI was likewise classified into serious biological damage (SBD) and light biological damage (LBD). Finally, the damaged area was graded into four categories: (a) SPD and SBD, (b) LPD and SBD, (c) SPD and LBD, and (d) LPD and LBD. The accuracy assessment for the area classified into four grades showed an overall accuracy of 0.74, and a kappa value of 0.61 which provides improvement over previous works

The efficacy of tenofovir-based therapy in patients showing suboptimal response to entecavir-adefovir combination therapy

Background/Aims: Before tenofovir (TDF) become available in South Korea, combination therapy with entecavir (ETV) and adefovir (ADV) was the most potent regimen for chronic hepatitis B (CHB) patients who fail to respond to rescue therapy for drug resistance. We analyzed the efficacy of ETV-ADV combination therapy and investigated the clinical and clonal results of TDF-based rescue therapy in CHB patients refractory to this combination. Methods: We retrospectively reviewed the medical records of CHB patients treated for up to 3 years with ETV-ADV combination therapy as a rescue therapy for drug resistance. In cases refractory to this combination, clinical and clonal analyses were performed for TDF-based rescue therapy. Results: The analysis was performed on 48 patients. Twelve patients achieved a virological response (VR) within 3 years. A VR was subsequently achieved in nine of the ten patients without a VR who switched to TDF monotherapy. A VR was also achieved in six of the seven patients who switched to lamivudine-TDF combination therapy, and in two of the two patients who switched to ETV-TDF combination therapy. In an in vitro susceptibility test, viral replication was detected with TDF monotherapy but not with ETV-TDF combination therapy. Conclusions: The efficacy of ETV-ADV combination therapy was insufficient in CHB patients who were refractory to rescue therapy. A more potent regimen such as ETV-TDF combination therapy may be considered in such refractory cases

Vascular effects of estrogen in type II diabetic postmenopausal women

AbstractOBJECTIVESWe assessed the effects of estrogen on vascular dilatory and other homeostatic functions potentially affected by nitric oxide (NO)-potentiating properties in type II diabetic postmenopausal women.BACKGROUNDThere is a higher cardiovascular risk in diabetic women than in nondiabetic women. This would suggest that women with diabetes do not have the cardioprotection associated with estrogen.METHODSWe administered placebo or conjugated equine estrogen, 0.625 mg/day for 8 weeks, to 20 type II diabetic postmenopausal women in a randomized, double-blinded, placebo-controlled, cross-over design.RESULTSCompared with placebo, estrogen tended to lower low-density lipoprotein (LDL) cholesterol levels by 15 ± 23% (p = 0.007) and increase high-density lipoprotein (HDL) cholesterol levels by 8 ± 16% (p = 0.034). Thus, the ratio of LDL to HDL cholesterol levels significantly decreased with estrogen, by 20 ± 24%, as compared with placebo (p = 0.001). Compared with placebo, estrogen tended to increase triglyceride levels by 16 ± 48% and lower glycosylated hemoglobin levels by 3 ± 13% (p = 0.295 and p = 0.199, respectively). However, estrogen did not significantly improve the percent flow-mediated dilatory response to hyperemia (17 ± 75% vs. placebo; p = 0.501). The statistical power to accept our observation was 81.5%. Compared with placebo, estrogen did not significantly change E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1 or matrix metalloproteinase-9 levels. Compared with placebo, estrogen tended to decrease tissue factor antigen and increase tissue factor activity levels by 7 ± 46% and 5 ± 34%, respectively (p = 0.321 and p = 0.117, respectively) and lower plasminogen activator inhibitor-1 levels by 16 ± 31% (p = 0.043).CONCLUSIONSThe effects of estrogen on endothelial, vascular dilatory and other homeostatic functions were less apparent in type II diabetic postmenopausal women, despite the beneficial effects of estrogen on lipoprotein levels

Characteristics of Sawdust and Cocopeat Beddings, and Their Usefulness According to the Fan and Pen Location for Rearing Hanwoo Cattle

This study was designed to examine the characteristics of sawdust and cocopeat bedding materials, including physicochemical properties (Exp. I) and on-farm trial (Exp. II). In Exp. I, the proportion of particle size was in the order of sawdust> cocopeat India>cocopeat Vietnam (pcocopeat Vietnam>sawdust (p<0.05), thus cocopeat treatments showed 4.4 times higher bedding cost than sawdust. The water absorption rates were 702.0% in cocopeat India, 678.3% in cocopeat Vietnam, and 444.0% in sawdust, showing cocopeat had approximately 1.5 times higher water absorption rate than sawdust. Moisture evaporation rates after 12 h of air blowing (2.00 m/s) were higher (p<0.05) in cocopeat Vietnam (80.4%) than sawdust (71.2%) and cocopeat India (72.8%). In vitro ammonia emissions were higher (p<0.05) in sawdust (2.71 mg/m2/h) than cocopeat India (1.59 mg/m2/h) and Vietnam (1.22 mg/m2/h), and total ammonia emissions were higher (p<0.05) in sawdust (37.02 mg/m2) than cocopeat India (22.51 mg/m2) and Vietnam (13.60 mg/m2). In Exp. II, an on-farm trial was conducted with 48 Hanwoo cattle in 16 pens using the same bedding materials as in Exp. I, with fan (blowing 2.00 m/s) and no fan treatments, and feed bunk side (FB) and water supply side (WS) within a pen (4.5 m, width×9.0 m, length). Beddings were replaced with fresh bedding materials when moisture concentrations were over 65%. No interactions among treatments were detected for moisture concentration and increment rates, and ammonia concentrations, but a significant effect was observed (p<0.01) for each of the treatments. Both concentrations and increment rate of moisture were higher (p<0.01) in the beddings without fan than with fan. Moisture concentrations and increment rate within a pen were also higher (p<0.01) in FB than WS. Thus, the whole no-fan-FB and sawdust-fan-FB were replaced with fresh bedding material between 4 to 5 experimental weeks. The ammonia concentrations and pH of beddings were not significantly different among treatments. Therefore, using cocopeat bedding with a blowing fan can extend twice the bedding utilization period, and WS within a pen showed twice the bedding-life compared to FB. Despite the outstanding characteristics of cocopeat compared with sawdust, using cocopeat as an alternative for sawdust bedding is not recommended for cattle management, considering it has 4.4 times higher bedding cost and a dust production problem

Characteristics of Classified Aerosol Types in South Korea during the MAPS-Seoul Campaign

During the Megacity Air Pollution Studies-Seoul (MAPS-Seoul) campaign from May to June 2015, aerosol optical properties in Korea were obtained based on the AERONET sunphotometer measurement at five sites (Anmyon, Gangneung_WNU, Gosan_SNU, Hankuk_UFS, and Yonsei_University). Using this dataset, we examine regional aerosol types by applying a number of known aerosol classification methods. We thoroughly utilize five different methods to categorize the regional aerosol types and evaluate the results from each method by inter-comparison. The differences and similarities among the results are also discussed, contingent upon the usage of AERONET inversion products, such as the single scattering albedo. Despite several small differences, all five methods suggest the same general features in terms of the regionally dominant aerosol type: Fine-mode aerosols with highly absorbing radiative properties dominate at HankukUFS and Yonsei_University; non-absorbing fine-mode particles form a large portion of the aerosol at Gosan_SNU; and coarse-mode particles cause some effects at Anmyon. The analysis of 3-day back-trajectories is also performed to determine the relationship between classified types at each site and the regional transport pattern. In particular, the spatiotemporally short-scale transport appears to have a large influence on the local aerosol properties. As a result, we find that the domestic emission in Korea significantly contributes to the high dominance of radiation-absorbing aerosols in the Seoul metropolitan area and the air-mass transport from China largely affects the western coastal sites, such as Anmyon and Gosan_SNU

Spontaneous HBsAg loss in Korean patients: relevance of viral genotypes, S gene mutations, and covalently closed circular DNA copy numbers

Background/AimsOccult HBV infection can persist following HBsAg loss and be transmitted, but the virological features are not well defined.MethodsHere we investigated 25 Korean patients who lost HBsAg during follow up, either spontaneously or subsequent to therapy.ResultsWhereas subtype adr (genotype C) was found in 96% of HBsAg positive patients, 75 % of patients who lost HBsAg spontaneously were seemed to be infected with the ayw subtype with sequence similar to genotype D. Mutations in the major hydrophilic region (MHR) of HBsAg were found in 7 patients who lost HBsAg spontaneously. The mutations include T123S, M125I/N, C139R, D144E, V177A, L192F, and W196L, some of which have not been reported before. Functional analysis via transfection experiments indicate that the C139R and D144E mutations drastically reduced HBsAg antigenicity, while the Y225del mutation found in one interferon-treated patient impaired HBsAg secretion.ConclusionsLack of detectable HBsAg in patient serum could be explained by low level of ccc DNA in liver tissue, low antigenicity of the surface protein, or its secretion defect

Long-Pulsed Nd:YAG Laser Treatment of Warts: Report on a Series of 369 Cases

Various treatment methods have been adopted in the management of warts; however, there is still no consensus on first-line treatment. This study was designed to evaluate the efficacy of long-pulsed Nd:YAG laser in the treatment of warts. Over the course of 1 yr, 369 patients with recalcitrant or untreated warts were exposed to a long-pulsed Nd:YAG laser. The following parameters were used: spot size, 5 mm; pulse duration, 20 msec; and fluence, 200 J/cm2. No concomitant topical treatment was used. In all, 21 patients were lost during follow up; hence, the data for 348 patients were evaluated. The clearance rate was 96% (336 of the 348 treated warts were eradicated). The clearance rate of verruca vulgaris after the first treatment was very high (72.6%), whereas the clearance rate of deep palmopantar warts after the first treatment was low (44.1%). During a median follow-up period of 2.24 months (range, 2-10 months), 11 relapses were seen (recurrence rate, 3.27%). In conclusion, long-pulsed Nd:YAG laser is safe and effective for the removal or reduction of warts and is less dependent on patient compliance than are other treatment options