Dimensional Responses of Wood Under Cyclical Changing Temperature at Constant Relative Humidity

Tiantian Yang,Erni Ma,Yi Shi 한국목재공학회 2015 목재공학 Vol.43 No.5

To investigate dimensional responses of wood under dynamic temperature condition, poplar (populous euramericana Cv.) specimens, 20 mm in radial (R) and tangential (T) directions with two thicknesses of 4 and 10 mm along the grain, were exposed to cyclic temperature changes in square wave between 25℃ and 40℃ at 60% relative humidity (RH) for three different cycling periods of 6 h, 12 h and 24 h. R and T dimensional changes measured during the cycling gave the following results: 1) Transverse dimensional changes of the specimens were generally square but at an opposite phase and lagged behind the imposed temperature changes. The phase lag was inversely correlated with cycling period, but positively related to specimen thickness, while the response amplitude was directly proportional to cycling period, but in a negative correlation with specimen thickness. 2) The specimens showed swelling hysteresis behavior. The heat shrinkage coefficient (HSC) became greater as cycling period increased or specimen thickness decreased. 3) Dimensional changes of the specimens produced deformation accumulation during repeated adsorption and desorption. The deformation accumulating ratio decreased with an increase in cycling period and specimen thickness. 4) Wood suffered 1.5 times as many dimensional changes per unit temperature variation as per unit humidity variation, and this deformation behaved even more seriously under static condition.

The mechanism of photocurrent enhancement of ZnO ultraviolet photodetector by reduced graphene oxide

Tiantian Yang,Bin Sun,Lei Ni,Xing Wei,Tingting Guo,Zhemin Shi,Fei Han,Li Duan 한국물리학회 2018 Current Applied Physics Vol.18 No.8

An ultraviolet (UV) photodetector based on ZnO-reduced graphene oxide (ZnO-rGO) composites have been successfully fabricated. A pure ZnO photodetector was also fabricated by similar method. In comparison with the pure ZnO UV photodetector, the ZnO-rGO photodetector exhibits a much larger photocurrent and a better lightto- dark-current-ratio. The mechanism of photocurrent enhancement was investigated using I-V characteristics, photoluminescence (PL) spectra, transmittance spectra and time-dependent photocurrent analysis. Results show that the photocurrent enhancement of the ultraviolet photodetector is due to the improvement of the carrier lifetime, because the carrier recombination of ZnO were reduced by rGO. It provides a potential way to fabricate high-response UV photodetectors.

Comparison of Dynamic Sorption and Hygroexpansion of Wood by Different Cyclic Hygrothermal Changing Effects

Tiantian Yang,Erni Ma 한국목재공학회 2016 목재공학 Vol.44 No.2

To investigate the dynamic sorptive and hygroexpansive behaviors of wood by different cyclic hygrothermal changing effects, poplar (populus euramericana Cv.) specimens, were exposed to dynamic sorption processes where relative humidity (RH) and temperature changed simultaneously in sinusoidal waves at 75-45% and 5-35℃ (condition A) and where RH changed sinusoidally at 75-45% but temperature was controlled at 20℃ (condition B), both for three cyclic periods of 1, 6, and 24 h. Moisture and dimensional changes measured during the cycling gave the following results: Moisture and transverse dimensional changes were generally sinusoidal. Moisture and dimensional amplitude increased with increasing cyclic period but all were lower for thicker specimens. The amplitude ratio of condition A to condition B ranged from 1.0 to 1.6 with the maximum value of 1.57 occurring at the shortest cyclic period, not as much as expected. T/R increased as cyclic period increased or specimen thickness decreased. T/R from condition B was weaker than that from condition A. Sorption and swelling hysteresis existed in both conditions. Sorption hysteresis was negatively related to cyclic period but in positive correlation with specimen thickness. Sorption hysteresis was found more obvious in condition B, while moisture sorption coefficient and humidity expansion coefficient showed the opposite results.

Variations of SSU rDNA Group I Introns in Different Isolates of Cordyceps militaris and the Loss of an Intron during Cross-Mating

Tiantian Lian,Tao Yang,Junde Sun,Suping Guo,Huaijun Yang,Caihong Dong 한국미생물학회 2014 The journal of microbiology Vol.52 No.8

Cordyceps militaris, the type species of genus Cordyceps, isone of the most popular mushrooms and a nutraceutical ineastern Asia. It is considered a model organism for thestudy of Cordyceps species because it can complete its lifecycle when cultured in vitro. In the present study, the occurrenceand sequence variation of SSU rDNA group I introns,Cmi.S943 and Cmi.S1199, among different isolatesof C. militaris were analyzed. Based on the secondary structurepredictions, the Cmi.S943 intron has been placed insubgroup IC1, and the Cmi.S1199 intron has been placedin subgroup IE. No significant similarity between Cmi.S943and Cmi.S1199 suggested different origins. Three genotypes,based on the frequency and distribution of introns, were describedto discriminate the 57 surveyed C. militaris strains. It was found that the genotype was related to the stromacharacteristics. The stromata of all of the genotype II strains,which possessed only Cmi.S943, could produce perithecium. In contrast, the stromata of all genotype III strains, whichhad both Cmi.S943 and Cmi.S1199, could not produce perithecium. Cmi.S1199 showed the lowest level of intra-specificvariation among the tested strains. Group I introns can belost during strain cross-mating. Therefore, we presumed thatduring cross-mating and recombination, intron loss could bedriven by positive Darwinian selection due to the energeticcost of transcribing long introns.

Experimental study on thermo-hydraulic performance of nanofluids in diverse axial ratio elliptical tubes with a built-in turbulator

Cong Qi,Tiantian Chen,Yuxing Wang,Liyuan Yang 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.9

Due to the low heat transfer efficiency of common heat exchange systems, an improved heat exchange system was developed. Enhanced tubes (elliptical tubes with a built-in turbulator) instead of a smooth tube were used and TiO2-water nanofluids were substituted for water to intensify the heat transfer. The influences of turbulator (presence or absence), axial ratios of elliptical tubes (Z=1.235, 1.471, 1.706), nanoparticle concentration (=0.0 wt%, 0.1 wt%, 0.3 wt%, 0.5 wt%), and Reynolds number (Re=400-12,000) on the flow and heat transfer properties of TiO2-water nanofluids were studied. Thermal and exergy efficiency were used to research the comprehensive thermo-hydraulic characteristics of these heat transfer enhancement technologies. The thermo-hydraulic properties of nanofluids all showed an increasing trend with the growing axial ratio, nanoparticle concentration and Reynolds number. Nanofluids (=0.5 wt%) in an elliptical tube (Z=1.706) with a built-in turbulator showed the best thermal performance, which could be increased by 33.8% in comparison with water at best. The thermal efficiency index increased first and then decreased with the Re. Nanofluids in elliptical tubes with a built-in turbulator can clearly promote heat transfer under the identical condition.

Screening and Molecular Cloning of a Protective Antigen from the Midgut of Haemaphysalis longicornis

Yonghong Hu,Jincheng Zhang,Shujie Yang,Hui Wang,Hua Zeng,Tiantian Zhang,Jingze Liu 대한기생충학열대의학회 2013 The Korean Journal of Parasitology Vol.51 No.3

Treatment performance and N2O emission in the UASB-A/O shortcut biological nitrogen removal system for landfill leachate at different salinity

Mu Liu,Yongzhen Peng,Qing Yang,Tiantian Liu, Han Xiao,Shuying Wang 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.32 No.-

Landfill leachate was treated using the upflow anaerobic sludge blanket (UASB) combined with anoxic/aerobic reactor (A/O) for shortcut biological nitrogen removal. The treatment performance and nitrousoxide (N2O) emission were studied under different salinity. When salinity increased from 10 to 35 g/L,the removal efficiency of ammonium nitrogen and total nitrogen decreased from 99.3 to 83.9% and from85.4 to 68.4%, respectively while the nitrite accumulation rate always remained high at more than 94.3%. The N2O conversion ratio increased by 14.7 times, from 0.3 to 4.7%. The concentration of biodegradableCOD in influent of the A/O reactor increased with the increase of salinity, which lead to the decrease ofdissolved oxygen and thus stimulated N2O emission remarkably during the aerobic zone. Meanwhile, theN2O emissions were likely to occur by a combination of pathways since the simultaneous nitritation anddenitritation was occurred in aerobic zone. The increase of NH4+-N concentration, NO2-N concentrationand pH caused by high salinity also promoted the N2O emission. The population of Nitrosomonaseuropaea increased with salinity, which was important for N2O emission.

The effect of canagliflozin on gut microbiota and metabolites in type 2 diabetic mice

Zeng Li,Ma Jideng,Wei Tiantian,Wang Hao,Yang Guitao,Han Chongxiang,Zhu Tao,Tian Haoming,Zhang Min 한국유전학회 2024 Genes & Genomics Vol.46 No.5

Background Sodium glucose cotransporter 2 inhibitor (SGLT2i) represent a new type of hypoglycemic medicine that can cause massive loss of glucose from the urine, which have several benefits of reducing body weight and improving the prognosis of cardiovascular and kidney diseases. Although they are oral medicated hypoglycemic agents, their effects on the gut microbiome and function have been unclear. Objective In order to describe the effects of canagliflozin on intestinal flora and metabolites, diabetic mice were randomized to receive canagliflozin or isoconcentration carboxymethylcellulose sodium by gavage for 8 weeks. Feces were collected for 16 S rRNA gene and LC-MS/MS analysis and enriched metabolic pathways through Kyoto Encyclopedia of Genes and Genomes (KEGG). Liver, muscle, intestinal, fat were collected for qRT-PCR according to KEGG enriched metabolic pathways. Results Our results showed that canagliflozin significantly increased GLP-1 level and impacted on the composition of gut microbiota and metabolites. It mainly increased Muribaculum, Ruminococcaceae_UCG_014, Lachnospiraceae-UCG-001, decreased ursodeoxycholic acids (UDCA) and hyodeoxycholic acids (HDCA), and increased fatty acids metabolites in feces. Conclusion In conclusion, we analyzed the changes of intestinal microbial composition and metabolites in diabetic mice after canagliflozin intervention and found that canagliflozin influenced intestinal fatty acid and bile acid (BA) metabolism. This study will provide reference for subsequent SGLT2i and intestinal related research. Background Sodium glucose cotransporter 2 inhibitor (SGLT2i) represent a new type of hypoglycemic medicine that can cause massive loss of glucose from the urine, which have several benefits of reducing body weight and improving the prognosis of cardiovascular and kidney diseases. Although they are oral medicated hypoglycemic agents, their effects on the gut microbiome and function have been unclear. Objective In order to describe the effects of canagliflozin on intestinal flora and metabolites, diabetic mice were randomized to receive canagliflozin or isoconcentration carboxymethylcellulose sodium by gavage for 8 weeks. Feces were collected for 16 S rRNA gene and LC-MS/MS analysis and enriched metabolic pathways through Kyoto Encyclopedia of Genes and Genomes (KEGG). Liver, muscle, intestinal, fat were collected for qRT-PCR according to KEGG enriched metabolic pathways. Results Our results showed that canagliflozin significantly increased GLP-1 level and impacted on the composition of gut microbiota and metabolites. It mainly increased Muribaculum, Ruminococcaceae_UCG_014, Lachnospiraceae-UCG-001, decreased ursodeoxycholic acids (UDCA) and hyodeoxycholic acids (HDCA), and increased fatty acids metabolites in feces. Conclusion In conclusion, we analyzed the changes of intestinal microbial composition and metabolites in diabetic mice after canagliflozin intervention and found that canagliflozin influenced intestinal fatty acid and bile acid (BA) metabolism. This study will provide reference for subsequent SGLT2i and intestinal related research.

Effects of Fdft 1 gene silencing and VD3 intervention on lung injury in hypoxia-stressed rats

Pu Xiaoyan,Lin Xue,Qi Yinglian,Li Yinglian,Li Tiantian,Liu Yang,Wei Dengbang 한국유전학회 2022 Genes & Genomics Vol.44 No.10

Background: Hypoxia can induce lung injury such as pulmonary arterial hypertension and pulmonary edema. And in the rat model of hypoxia-induced lung injury, the expression of Farnesyl diphosphate farnesyl transferase 1 (Fdft 1) was highly expressed and the steroid biosynthesis pathway was activated. However, the role of Fdft 1 and steroid biosynthesis pathway in hypoxia-induced lung injury remains unclear. Objective: The study aimed to further investigate the relationship between Fdft1 and steroid biosynthesis pathway with hypoxia-induced lung injury. Methods: A rat model of lung injury was constructed by hypobaric chamber with hypoxic stress, the adenovirus interference vector was used to silence the expression of Fdft 1, and the exogenous steroid biosynthesis metabolite Vitamin D3 (VD3) was used to treat acute hypoxia-induced lung injury in rats. Results: Sh-Fdft 1 and exogenous VD3 significantly inhibited the expression of Fdft 1 and the activation of the steroid pathway in hypoxia-induced lung injury rats, which showed a synergistic effect on the steroid activation pathway. In addition, sh-Fdft 1 promoted the increase of pulmonary artery pressure and lung water content, the decrease of oxygen partial pressure and oxygen saturation, and leaded to the increase of lung cell apoptosis and the aggravation of mitochondrial damage in hypoxia-stressed rats. And VD3 could significantly improve the lung injury induced by hypoxia and sh-Fdft 1 in rats. Conclusions: Fdft 1 gene silencing can promote hypoxic-induced lung injury, and exogenous supplement of VD3 has an antagonistic effect on lung injury induced by Fdft 1 gene silencing and hypoxic in rats, suggesting that VD3 has a preventive and protective effect on the occurrence and development of hypoxia-induced lung injury.

Gene Cloning, Expression and Immunogenicity of the Protective Antigen Subolesin in Dermacentor silvarum

Yonghong Hu,Hua Zeng,Jincheng Zhang,Duo Wang,Dongming Li,Tiantian Zhang,Shujie Yang,Jingze Liu 대한기생충학열대의학회 2014 The Korean Journal of Parasitology Vol.52 No.1