First-to-second-order magnetic-phase transformation in La_0.7Ca_0.3-xBa_xMnO₃ exhibiting large magnetocaloric effect

Phan, T.L.,Dang, N.T.,Ho, T.A.,Manh, T.V.,Thanh, T.D.,Jung, C.U.,Lee, B.W.,Le, A.T.,Phan, A.D.,Yu, S.C. Elsevier Sequoia 2016 Journal of alloys and compounds Vol.657 No.-

We have prepared polycrystalline samples La<SUB>0.7</SUB>Ca<SUB>0.3-x</SUB>Ba<SUB>x</SUB>MnO<SUB>3</SUB> (x = 0, 0.025, 0.05, 0.075 and 0.1) by solid-state reaction, and then studied their magnetic properties and magnetocaloric (MC) effect based on magnetization versus temperature and magnetic-field (M-H-T) measurements. Experimental results reveal the easiness in tuning the Curie temperature (T<SUB>C</SUB>) from 260 to about 300 K by increasing Ba-doping concentration (x) from 0 to 0.1. Under an applied field H = 50 kOe, maximum magnetic-entropy changes around T<SUB>C</SUB> of the samples can be tuned in the range between 6 and 11 J kg<SUP>-1</SUP> K<SUP>-1</SUP>, corresponding to refrigerant-capacity values ranging from 190 to 250 J kg<SUP>-1</SUP>. These values are comparable to those of some conventional MC materials, and reveal the applicability of La<SUB>0.7</SUB>Ca<SUB>0.3-x</SUB>Ba<SUB>x</SUB>MnO<SUB>3</SUB> materials in magnetic refrigeration. Analyses of the critical behavior based on the Banerjee criteria, Arrott plots and scaling hypothesis for M-H-T data prove a magnetic-phase separation when Ba-doping concentration changes. In the doping region x = 0.05-0.075, the samples exhibits the crossover of first- and second-order phase transitions with the values of critical exponents β and γ close to those expected for the tricritical mean-field theory. The samples with x < 0.05 and x > 0.075 exhibit first- and second-order transitions, respectively. More detailed analyses related to the Griffiths singularity, the critical behavior for different magnetic-field intervals started from 10 kOe, and the magnetic-ordering parameter n = dLn|ΔS<SUB>m</SUB>|/dLnH (where ΔS<SUB>m</SUB> is the magnetic-entropy change) demonstrate magnetic inhomogeneities and multicritical phenomena existing in the samples.

Development of thermostable lipase B from Candida antarctica (CalB) through in silico design employing B-factor and RosettaDesign

Kim, H.S.,Le, Q.A.T.,Kim, Y.H. IPC Science and Technology Press ; Elsevier Scienc 2010 Enzyme and microbial technology Vol.47 No.1

Organic synthesis reactions demand improved characteristics of enzymes than wild type such as reactivity, thermostability, enantioselectivity and so on. Especially thermostability of enzyme is highly important since reaction at higher temperature has many advantages such as elevated reaction rate and increased solubility of substrates. Due to this requirement, a rational approach was employed to develop thermostable CalB. The first step of this approach was the selection of appropriate sites showing a high 'B-factor' value. These sites were chosen on the basis of atomic displacement parameters obtained from X-ray data. These selected sites were then substituted with other amino acids that were determined to be more rigid than the original amino acids by computational modeling using 'RosettaDesign'. As a result of this rational approach, several thermostable CalB mutants including R249L were produced. The residual activity of R249L CalB was two times higher than that of wild type CalB at 55<SUP>o</SUP>. Melting temperature (T<SUB>m</SUB> of R249L mutant increased to 56.8<SUP>o</SUP> compared with wild type CalB (T<SUB>m</SUB> 54.5<SUP>o</SUP>), which was determined by DSF (differential scanning fluorimetry). Additionally, packing analysis tool ''Voronoia'' pointed out that one cavity close to residue 249 of wild type CalB disappeared in CalB R249L, which could be the reason for the increase in thermal stability of CalB R249L mutant compared wild type CalB.

Room Temperature Magnetocaloric Effect in <tex> ${\hbox{La}}_{0.7}{\hbox{Sr}}_{0.3}{\hbox{Mn}}_{1\hbox{-}{\rm x}}{\hbox{Co}}_{\rm x}{\hbox{O}}_{3}$</tex>

Tran Dang Thanh,Le Viet Bau,Phan, T. L.,Yu, S. C. IEEE 2014 IEEE transactions on magnetics Vol.50 No.1

<P>We have investigated the magnetic properties and magnetocaloric effect in La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB> prepared by a conventional solid-state reaction method. Magnetic measurements versus temperature revealed that the Curie temperature (T<SUB>C</SUB>) decreased gradually with increasing Co content (x); T<SUB>C</SUB> values are about 360, 310, 296 and 280 K for x =0.0, 0.06, 0.08 and 0.1, respectively. Magnetic entropy change (ΔS<SUB>m</SUB>) of the samples under a magnetic field change of 10 kOe was calculated by using isothermal magnetization data. We have found its maximum (|ΔS<SUB>max</SUB>|) achieved around T<SUB>C</SUB>, which is not changed much (~ 1.5 J·kg<SUP>-1</SUP>·K<SUP>-1</SUP>) with increasing Co-doping concentration. If combining the samples with x = 0.06, 0.08 and 0.10 for magnetic refrigeration, particularly, the temperature range can be used in between 266 K and 322 K, where |ΔS<SUB>max</SUB>| values are stable at about 0.98 J·kg<SUP>-1</SUP>·K<SUP>-1</SUP>. The relative cooling power is accordingly about 55 J·kg<SUP>-1</SUP> and comparable to that of other magnetocaloric alloys. These results suggest La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>Mn<SUB>1-x</SUB>Co<SUB>x</SUB>O<SUB>3</SUB> compounds to be a potential candidate for magnetic refrigerators at room temperature.</P>

The reproduction potentials of four entomopathogenic nematode strains related to cost-effective production for biological control

Chau Nguyen N.,Anh Le T.,Vu Nguyen H.,Phuc Hoang K. 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.2

Bioassays to evaluate the mortality, virulence and reproduction potentials of four indigenous EPN strains, SPQ16, S-BM12, H-KT3987 and H-CB3452 on insect larvae of mealworm (Tenebrio molitor) and greater wax moth (Galleria mellonella) revealed the highest mortality rates of two insect larvae at the highest inoculation dose of 100 IJs to range from 89 to 100 percent and 94.3–100 percent at 48 h after inoculation, respectively. Virulence was high for all nematode strains, with LC 50 values between 29.6 and 47.3 IJs/insect host. The highest IJ yields were different between nematode strains and insect host, from 66.8 × 10 3 IJs (S-PQ16) to 118.6 × 10 3 IJs (HKT3987) on T. molitor, and from 54.2 × 10 3 IJs (S-BM12) to 163.3 × 10 3 IJs (H-KT3987) on G. mellonella. The culturing cost in terms of food expenditure for rearing insect larvae varied between insect larvae and nematode strains, from 6.76 to 26.63 USD per billion IJs for nematode strains cultured on T. molitor larvae and from 3.54 to 7.81 USD per billion IJs for nematode strains cultured on G. mellonella larvae. The full cost for a nematode product of 2.5 × 10 9 IJs per hectare, produced through in vivo mass culturing, of the most efficient nematode strain, H-KT3987, was 191.3 USD, slightly cheaper than 199.4 USD for the same nematode product produced through in vitro mass culturing.

Intravascular schwannoma as an extremely unusual cause of vein obstruction: a case report

Luis Miguel Chinchilla-Tábora,Beatriz Segovia Blázquez,José María Sayagués,Marta Rodríguez González,Joaquín González-Rivero,José Antonio Muñoz León,Andrea Beatriz Jiménez Pérez,Idalia González Morais 대한병리학회 2024 Journal of Pathology and Translational Medicine Vol.58 No.5

The blood vessel lumen is an extremely rare location for a benign peripheral nerve sheath tumor like schwannoma. Less than 10 cases have been previously reported. In this report, we present a case of a 68-year-old woman who had a soft tissue nodule at the posterior calf of her left leg during a physical examination. Pathological examination was performed after complete surgical excision. The patient underwent follow-up for 12 months after surgery without evidence of recurrence or any other complication. This is the first case of intravascular schwannoma reported as a cause of vein obstruction. Microscopically, the tumor was composed of Schwann spindle cells that were immunoreactive for S100 protein and SOX10. This tumor was surrounded by a well-defined vascular smooth muscle wall. Prospective series are required to improve the knowledge on the underlying mechanisms of intravascular schwannoma development.

Effect of stress during slaughter on carcass characteristics and meat quality in tropical beef cattle

Carrasco-García Apolo A.,Pardío-Sedas Violeta T.,León-Banda Gloria G.,Ahuja-Aguirre Concepción,Paredes-Ramos Pedro,Hernández-Cruz Bertha C.,Murillo Vicente Vega 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.10

Objective: This study aimed to determine the effects of stress during slaughter of beef cattle on physiological parameters, carcass, and meat quality at a Federal Inspection Type slaughterhouse located in the southeast of Mexico. Methods: A total of 448 carcasses of male Zebu×European steers with an average age of 36 months were included. Carcass assessment of presence of bruises and bruise characteristics was carried out on each half-carcass. Blood variable indicators of stress (packed cell volume, neutrophil to lymphocyte ratio, glucose, cortisol concentration) and meat quality parameters (pH, color, shear force, drip loss) were evaluated. Results: Of the 448 carcasses evaluated, 81% of the carcasses showed at least one bruise; one bruise was detected in 36.6% and two bruises in 27.0% of animals. Of the 775 bruises found, 69.2% of the bruises were grade 1 in region 3. Of the 448 carcasses studied, 69.6% showed hyperglycemia (6.91 mmol/L); 44.3% and 22.7% showed high (74.7 ng/mL) and extremely high (108.8 ng/mL) cortisol levels, respectively, indicative of inadequate handling of animals during preslaughter and slaughter. Of the carcasses evaluated, 90.4% had a pH ≥5.8 with an average of pH 6.3. In both pH groups, meat samples showed L* values >37.0 (81.6%) and a shear force >54.3 N; meat pH≥5.8 group showed a drip loss of 2.5%. These findings were indicative of dark, firm, and dry (DFD) meat. According to principal component analysis, grades 1 and 2 bruises in region 3 and grade 1 bruises in region 5 were highly associated with cortisol, drip loss, and color parameters b* and h* and were negatively associated with L*, a*, and C*. Conclusion: The bruises probably caused by stress-inducing situations triggered DFD meat. Appropriate changes in handling routines in operating conditions should be made to minimize stress to animals during the slaughter process to improve animal welfare and meat quality.

Discordance between quantitative ultrasound and dual-energy X-ray absorptiometry in bone mineral density: The Vietnam Osteoporosis Study

Huy G. Nguyen,Khanh B. Lieu,Thao P. Ho-Le,Lan T. Ho-Pham,Tuan V. Nguyen 대한골다공증학회 2021 Osteoporosis and Sarcopenia Vol.7 No.1

Objectives: Calcaneal quantitative ultrasound measurement (QUS) has been considered an alternative to dual-energy X-ray absorptiometry (DXA) based bone mineral density (BMD) for assessing bone health. This study sought to examine the utility of QUS as an osteoporosis screening tool by evaluating the correlation between QUS and DXA. Methods: The study was a part of the Vietnam Osteoporosis Study that involved 1270 women and 773 men aged 18 years and older. BMD at the femoral neck, total hip and lumbar spine was measured using DXA. Osteoporosis was diagnosed based on the femoral neck T-score using World Health Organization criteria. Broadband ultrasound attenuation (BUA) at the calcaneus was measured by QUS. The concordance between BUA and BMD was analyzed by the linear regression model. Results: In all individuals, BUA modestly correlated with femoral neck BMD (r ¼ 0.35; P < 0.0001) and lumbar spine BMD (r ¼ 0.34; P < 0.0001) in both men and women. In individuals aged 50 years and older, approximately 16% (n ¼ 92/575) of women and 3.2% (n ¼ 10/314) of men were diagnosed to have osteoporosis. Only 0.9% (n ¼ 5/575) women and 1.0% (n ¼ 3/314) men were classified as “Low BUA”. The kappa coefficient of concordance between BMD and BUA classification was 0.09 (95% CI, 0.04 to 0.15) for women and 0.12 (95% CI, 0.03 to 0.22) for men. Conclusions: In this population-based study, QUS BUA modestly correlated with DXA BMD, suggesting that BUA is not a reliable method for screening of osteoporosis

Determining the risk factors associated with the development of Clostridium difficile infection in patients with hematological diseases

Yu Ling Lee-Tsai,Rodrigo Luna-Santiago,Roberta Demichelis-Gómez,Alfredo Ponce-de-León,Eric Ochoa-Hein,Karla María Tamez-Torres,María T Bourlon,Christianne Bourlon 대한혈액학회 2019 Blood Research Vol.54 No.2

BackgroundClostridium difficile infection (CDI) is a nosocomial condition prevalent in patients with hematological disorders. We aimed to identify the risk factors associated with the devel-opment of CDI and assess the mortality rate at 15 and 30 days among hematologic patients admitted to a tertiary care center.MethodsWe conducted a retrospective case-control study from January 2010 to December 2015. Forty-two patients with hematologic malignancy and CDI, and 84 with hematologic dis-ease and without history of CDI were included in the case and control groups, respectively.ResultsUnivariate analysis revealed that episodes of febrile neutropenia [odds ratio (OR), 5.5; 95% confidence interval (CI), 2.3‒12.9; P<0.001], admission to intensive care unit (OR, 3.8; 95% CI, 1.4‒10.2; P=0.009), gastrointestinal surgery (OR, 1.2; 95% CI, 1.1‒1.4; P<0.001), use of therapeutic (OR, 6.4; 95% CI, 2.5‒15.9; P<0.001) and prophylactic antibiotics (OR, 4.2; 95% CI, 1.6‒10.7; P=0.003) in the last 3 months, and >1 hospital-ization (OR, 5.6; 95% CI, 2.5‒12.6; P<0.001) were significant risk factors. Multivariate analysis showed that use of therapeutic antibiotics in the last 3 months (OR, 6.3; 95% CI, 2.1‒18.8; P=0.001) and >1 hospitalization (OR, 4.3; 95% CI, 1.7‒11.0; P=0.002) were independent risk factors. Three (7.1%) and 6 (14.2%) case patients died at 15 and 30 days, respectively.ConclusionThe risk factors for developing CDI were exposure to therapeutic antibiotics and previous hospitalization. Hematological patients who developed CDI had higher early mortality rates, suggesting that new approaches for prevention and treatment are needed.

Biogas Production from Vietnamese Animal Manure, Plant Residues and Organic Waste: Influence of Biomass Composition on Methane Yield

T.T.T. Cu,T.X. Nguyen,J.M. Triolo,L. Pedersen,V.D. Le,P.D. Le,S.G. Sommer 아세아·태평양축산학회 2015 Animal Bioscience Vol.28 No.2

Anaerobic digestion is an efficient and renewable energy technology that can produce biogas from a variety of biomasses such as animal manure, food waste and plant residues. In developing countries this technology is widely used for the production of biogas using local biomasses, but there is little information about the value of these biomasses for energy production. This study was therefore carried out with the objective of estimating the biogas production potential of typical Vietnamese biomasses such as animal manure, slaughterhouse waste and plant residues, and developing a model that relates methane (CH4) production to the chemical characteristics of the biomass. The biochemical methane potential (BMP) and biomass characteristics were measured. Results showed that piglet manure produced the highest CH4 yield of 443 normal litter (NL) CH4 kg–1 volatile solids (VS) compared to 222 from cows, 177 from sows, 172 from rabbits, 169 from goats and 153 from buffaloes. Methane production from duckweed (Spirodela polyrrhiza) was higher than from lawn grass and water spinach at 340, 220, and 110.6 NL CH4 kg–1 VS, respectively. The BMP experiment also demonstrated that the CH4 production was inhibited with chicken manure, slaughterhouse waste, cassava residue and shoe-making waste. Statistical analysis showed that lipid and lignin are the most significant predictors of BMP. The model was developed from knowledge that the BMP was related to biomass content of lipid, lignin and protein from manure and plant residues as a percentage of VS with coefficient of determination (R-square) at 0.95.This model was applied to calculate the CH4 yield for a household with 17 fattening pigs in the highlands and lowlands of northern Vietnam.

Highly regioselective hydroxylation of polydatin, a resveratrol glucoside, for one-step synthesis of astringin, a piceatannol glucoside, by P450 BM3

Le, T.K.,Jang, H.H.,Nguyen, H.T.H.,Doan, T.T.M.,Lee, G.Y.,Park, K.D.,Ahn, T.,Joung, Y.H.,Kang, H.S.,Yun, C.H. IPC Science and Technology Press ; Elsevier Scienc 2017 Enzyme and microbial technology Vol.97 No.-

<P>Enzymatic conversion of natural glycosides to their corresponding hydroxylated products using cytochromes P450 has significant advantages over synthetic chemistry and even enzyme-catalyzed glycosylation of chemicals. At present, the basic strategy for making glycosides of stilbenoid compounds is to use the glycosylation activity of enzymes, such as glycosyltransferases. Here, an efficient synthesis of a valuable (E)-astringin, a piceatannol glucoside, was developed using CYP102A1 via the highly regioselective C-3' hydroxylation of polydatin, a resveratrol glucoside. (E)-astringin is a high added value compound found in plants and wine. Benzylic hydroxylation of polydatin provides an attractive route to (E)-astringin, a catechol product. Thus far, chemical and enzymatic methods of producing (E)-astringin have not been developed. In the present study, a set of CYP102A1 mutants from Bacillus megaterium was found to catalyze regioselective hydroxylation of polydatin at the C-3' position to generate an (E)-astringin, a piceatannol glucoside. (C) 2016 Elsevier Inc. All rights reserved.</P>