Low Temperture Research Articles

Leveraging Atriplex hortensis choline monooxygenase to improve chilling tolerance in cotton

Low temperature is a major factor limiting seedling growth and the production of cotton (Gossypium hirsutum L.). However, enhancing chilling tolerance is typically negatively correlated with yield in agricultural production. Here, we demonstrate that transgenic cotton expressing Atriplex hortensis choline monooxygenase (AhCMO) greatly enhanced resistance to chilling stress. The promotion of chilling tolerance is mainly due to an increase in the content of osmoprotectants, especially glycine betaine and proline. The increased chilling tolerance was further verified at the molecular level using genome-wide expression profiling by RNA-sequencing. Further detailed analysis showed that the number of genes involved in scavenging of reactive oxygen species (ROS) was down-regulated and the activity of superoxide dismutase (SOD) and catalase (CAT) were decreased in AhCMO transgenic cotton compared with wild type after low temperture treatment. More importantly, overexpression of AhCMO in cotton moderately improved cotton fiber yield in normal growth condition. These data show that AhCMO transgenic cotton enhances low temperature tolerance via directly accumulating cellular osmoprotectants. Manipulating the expression of AhCMO by biotechnological tools could be a powerful method to enhance chilling tolerance in cotton.

SDS capped and PVA capped ZnO nanostructures with high photocatalytic performance toward photodegradation of reactive red (RR141) azo dye

Two types of ZnO nanostructures have been synthesized successfully in high yield by using either sodium dodecylsulfate (SDS) or polyvinyl alcohol (PVA) as a capping agent via a facile and low temperture chemical precipitation method. The synthesized ZnO samples show well crystallized wurtzite hexagonal phase. The SDS surfactant played a crucial effect on morphology, specific surface area and photocatalytic performance of the ZnO photocatalyst. SDS capped ZnO with high specific surface area of 14.8m2g−1 shows much higher photocatalytic performance in comparision to that of PVA capped ZnO. Nearly 95% and 88% of reactive red (RR141) azo dye decomposed after irradiation for 240min under UV light and 80min under solar light, respectively. The photodegradation reaction follows the pseudo first-order kinetics with the high rate constant (k) of 0.04min−1. The SDS capped ZnO photocatalyst retains its original efficiency of about 87% even after the third cycles of reuse indicating the advantages of stability and reusability. Hole and hydroxyl radical are the two major reactive species involving in photodegradation of azo dye. ZnO nanostructures with SDS as a capping agent will be suitable for photodegradation of organic pollutants in the environmental protection. The method and ideas presented herein will potentially provide cheaper and cleaner means for treatment of a large volume of organic dyes. The photodegradation process can be performed very easily even under solar light irradiation. This offers some insight into the progress of technological applications related to the degradation of industrial dyes.

B-47 低温式暖房の評価についての研究

B-47 低温式暖房の評価についての研究

17aB08 モノメチルシランを用いたCat-CVD法による微結晶SiCの低温成長(半導体エピ(2),第35回結晶成長国内会議)

17aB08 モノメチルシランを用いたCat-CVD法による微結晶SiCの低温成長(半導体エピ(2),第35回結晶成長国内会議)

The formation and characteristics of ZnO/AlN and ZnO/AlN/ZnO core-shell nanowires

ABSTRACTIn this work, we fabricate the p-type ZnO/AlN/ZnO core-shell nanowire arrays on Al2O3 substrate. The SEM images show the core-shell structure and the connection phenomenon appeared during the deposition process. The XRD results show a better crystal quality after annealing. The sample exhibits some unique properties after annealing treatment. Including the improvement of crystal quality and the shift of the PL emission peak. The low temperture PL spectra show a neutral acceptor bound exciton (A0X) emission (at 3.355 eV), and the emission at 3.325 eV is ascribe to the free electron to the acceptor transition (FA). The calculated result is found in good coincidence with the experiment.

Storage of human biospecimens: selection of the optimal storage temperature.

Millions of biological samples are currently kept at low tempertures in cryobanks/biorepositories for long-term storage. The quality of the biospecimen when thawed, however, is not only determined by processing of the biospecimen but the storage conditions as well. The overall objective of this article is to describe the scientific basis for selecting a storage temperature for a biospecimen based on current scientific understanding. To that end, this article reviews some physical basics of the temperature, nucleation, and ice crystal growth present in biological samples stored at low temperatures (-20°C to -196°C), and our current understanding of the role of temperature on the activity of degradative molecules present in biospecimens. The scientific literature relevant to the stability of specific biomarkers in human fluid, cell, and tissue biospecimens is also summarized for the range of temperatures between -20°C to -196°C. These studies demonstrate the importance of storage temperature on the stability of critical biomarkers for fluid, cell, and tissue biospecimens.

Respone of onion seedling s to some Inducing factors for flowering and seed production

The study was conducted during 2011-2012 season in Al usufyia district( 30 kmsouthern Baghdad) of onion seedling on Texsas Eerly Grano ( PRR) Var . treat theseedling with low Tempertures ( 5 , 10 and 15 Co ) for three periods (24, 48 and 72 h).the aim of the study was determing the best temperature that cause the high responseof flowering and high seed yeild . The results can summarized as follows :Thetreatment 5Co for 24 hr gave the best results in vegetative growth characters(number of tellers and neck diameter ) ( 1.733 teller / plant and 41.90 mm respecteflly )( earliar flowering ,flowering percentage , number of flowering bolter and thelength of flowering bolter ) ( 150 day , 87.33 % , 1.700 tiller / plant and 126 cm ,respect) , the seed yeild characters ( set percentage , Inflorecent weight and seed yeildin area ) ( 43 % , 15.40 gm / inf and 725.3 kg/ha ) respectefly significantly as controltreatmet .

Effect of nitrite on immunity of the white shrimp Litopenaeus vannamei at low temperture and low salinity

White shrimp Litopenaeus vannamei Boone (6-7 cm) were individually exposed during 8 h to 0 (control), 0.5, 1.0, and 10.0 mg/l NO(2)(-)-N at 22 °C and 10 ‰ salinity. Nitrite concentration was measured, and hemolymph and hepatopancreas were sampled at 0, 4 and 8 h. Superoxide dismutase (SOD) activity, catalase (CAT) activity, and malondialdehyde (MDA) in haemolymph and hepatopancreas of L. vannamei Boone, and hemocyanin were examined. The results indicated significant relationships among hemocyanin concentration (Hc), nitrite concentration (nt), and exposure time (t) was as following: Hc = 1.250 + 0.0360 nt + 0.0636t, (R(2) = 0.702, P < 0.01), and Gompertz models with 3-parameters was used to describe well the increase trend of Hc with increase of nitrite concentration at 4, 8 h, respectively (R(2) > 0.99, P ≤ 0.05). MDA level and CAT activity in hemolymph decreased significantly at 8 h, and MDA level and CAT activity in hepatopancreas increased markedly. The SOD activity in hepatopancreas remained almost stably in the range of 0.22-0.24 U/g Hb within 8 h. The results showed there existed a immune difference between in hemolymph and hepatopancreas after white shrimp exposed to ambient nitrite within 8 h, and further experiments should be designed to answer the reason.

Production of Oleic Acid Based Wax Ester Using Acidic Homogeneous Catalysts

Four homogeneous acidic catalysts were tested for their ability to catalyze the esterification reaction of oleic acid and oleyl alcohol to produce oleyl oleate, a wax ester. Sulfuric acid showed relatively higher specific activity. Various reaction parameters were optimised to obtain high percentage yield of oleyl oleate. The optimum condition to produce oeyl oleate was reaction time; 5 h, temperture; 90°C, amount of sulforic acid 0.15 g and molar ratio of oleyl alcohol to oleic acid; 1:1. Percentage yield of wax ester obtained at these optimum reaction conditions was 93.88. Disappearance of carboxylic acid (C=O) peak has confirmed by FTIR with appearance of ester (C=O) peak at 1739 cm−1. 1H NMR spectra analyses confirmed the result of oleyl oleate with appearance of ester (‐CH2OCOR) at 4.02 ppm and also the 13C‐NMR confirmed the result with appearance of ester (C=O) peak at 173.2 ppm. The low‐temperture behavior of compound synthesized was determined through its pour point (PP), viscosity index (VI) and flash point (FP) values. The results showed that oleyl oleate exhibited the most favorable low‐temperture performance of PP, VI and FP with −31°C, 197.5 and 320°C respectively. This is due to increase of the molacular weight thus improve the low temperture property significantly.

Analysis of the Crack Fracture Morphology of the Asphalt Mixture under Tensile Stress Effects

Through studying the bending fracture and cleavage fracture of the asphalt mixture within the different temperature condition, confirming that the temperature influences the microscopic mechanism of mixture cracking: the fracture is relatively flat with low temperture, the destruction of the asphalt mixture is also mainly result of the brittle fracture; As the temperature rise, fracture surface becomes coarse, some part show large plastic elapse deformation. Adding fiber can reduce thickness of the asphalt membrane, improve the bonding strength of asphalt mastic, and greatly increase the ratio of the aggregate fracture and interface zone fracture, so as to enhance the asphalt mixture crack-resistance. The fracture morphology of asphalt mixture has a better reflection for its mechanical characteristics.

Quadrupole Susceptibility and Elastic Softening due to a Vacancy in Silicon Crystal

We investigate the electronic states around a single vacancy in silicon crystal by using the Green's function approach. The triply degenerate vacancy states within the band gap are found to be extended over a large distance $\sim20 {\rm \AA}$ from the vacancy site and contribute to the reciprocal temperature dependence of the quadrupole susceptibility resulting in the elastic softening at low temperture. The Curie constant of the quadrupole susceptibility for the trigonal mode ($O_{yz},O_{zx},O_{xy}$) is largely enhanced as compared to that for the tetragonal mode ($O_{2}^{0},O_{2}^{2}$). The obtained results are consistent with the recent ultrasonic experiments in silicon crystal down to 20 mK. We also calculate the dipole and octupole susceptibilities and find that the octupole susceptibilities are extremely enhannced for a specific mode.

Low Temperture Au-Au Thermal Compression Bonding of Thermally Mismatched Substrates

One of the limitations in using metal bonding materials for the integration of compound semiconductors and silicon has been controlling the thermal expansion difference. Metal diffusion bonding using copper or gold generally requires annealing temperatures around 400C which is not compatible with heterogeneous materials bonding with large CTE mismatch. However, several processing modifications can be exploited to increase the diffusion rates, reduce annealing temperatures and control stresses in metal diffusion bonded substrates.

Low Temperture Au-Au Thermal Compression Bonding of Thermally Mismatched Substrates

not Available.

Clinical nursing reseach in prevention of intradialytic hypotension with hemodiaffitration

Objective To compare the effect of hemodiafiltration(HDF) on the incidence rate of intradialytie hypotension. Methods We followed up eighteen patients with symptomatic hypotension history and divided them into group A and group B.Group A was treated with conventional hemodialysis(CHD) and HDF, Group B adopted HDF with low temperture hemodialysis. The number of hypotensive episodes, blood temperature during cardiopulmonary bypass, energy transfer rates were assessed. Results The incidence of symptomatic hypotension of patients was found lower in CHD (40%) than in HDF (6%),P<0.01. Energy transfer rates were founded higher in CHD than in HDF and low temperture hemodialysis, P<0.01. Conclusions HDF significantly reduced hemodialysis-related side effects and increased the tolerance ability of patients. Key words: Hemodiafiltration; Intradialytie hypotension; Nursing Besearch

Distribution functions for a two-dimensional non-interacting quantum electron gas in an external magnetic field

The exact n-body distribution functions are calculated for a two-dimensional, non-interacting quantum electron gas in an external magnetic field for any temperature and density. At low tempertures and filled lowest Landau level (LLL), these functions are identical to the exact distribution functions obtained by Jancovici [1981, Phys. Rev. Lett., 46, 386] for the classical two-dimensional one-component plasma (2DOCP) at the special plasma parameter Γ = 2, thus establishing that the 2DOCP provides an exact classical Boltzmann factor which describes the ideal LLL quantum state associated with the integral quantum Hall effect.

Consistent picture of strong electron correlation from magnetoresistance and tunneling conductance measurements in multiwall carbon nanotubes

Both the magnetoconductance and the nonlinear differential conductance of multiwall carbon nanotube ropes have been studied at low temperture. Suppression in the differential conductance was observed at low bias voltages and at low temperatures, indicating the formation of a Coulomb gap. The magnetoconductance was found to follow a scaling law at both high and low temperatures, but with different mechanisms. The analysis of the data provides a sign of a non-Fermi-liquid-like behavior through magnetotransport measurement.

Halogen-Bridged Binuclear Metal Complexes Under Static Pressure

Two contrasting observations for halogen ( x )-bridged binuclear platinum complexes R 4 [Pt 2 O 5 H 2 )X] n H 2 O are interpreted by finite-temperature Hartree-Fock calculations. Assuming pressure-induced simultaneous increases of the interdimer electron transfer and Coulomb repulsiion, we reveal that an applied pressure turns the initial charge-polarization state into a charge-density-wave state at high tmperatures, while the charge-density-wave stte oppositely declines with increasing pressure at low tempertures. We predict pressure-induced phase transitions in another family of MMX complexes, Pt 2 (CH 3 CS 2 ) 4 I, as well. MMX chain pressure-induced phase transition Peierls-Hubbard model

Ｃｒ‐Ｍｏ鋼熱影響部の焼もどし脆化に関する研究 ５ ９００Ｋ以下の温度域におけるＨＡＺ焼もどし脆化の発生原因

The authors have pointed out in preceding papers that four types of temper arise in temperature range below 900 K when heat affected zone of 2 1/4Cr-lMo steel is reheated. The causes of these temper embrittlements were examined in present paper.The first type of which arises at 775 K was compared with the low temperture temper embrittlement which has been known to arise at 575 K and to be caused by fine precipitates of cementite. Experimental results on a series of specimens which were tempered at each temperature from 575 K to 775 K showed that both types of temper are identical.The second type of embrittlement, which arises at 825 K in short term range and produces cleavage fracture by impact test, was found to be caused by hardening of ferrite which was induced by fine precipitates of Mo2C type carbide.The thirdd type of arises at temperatures around 825 K and produces intergranular fracture by impact test. A new technique for analyzing grain boundary revealed that segregation of phosphorus caused this embrittlement.The fourth type of embrittlement, which arises at 875 K in long term range and produces cleavage fracture, was found to be caused by large sized particles of Mo2C type and Cr, C, type carbide. In impact test, fracture occurred preferentially along planes in which carbide particles of large size exist.The proper terms of first to fourth types of were proposed by authors : low-temperature-, short-term-, intergranular- and long-term temper embrittlement.

Band and Percolation Approaches to Low Temperature Properties of Manganites

Properties of the parent compound, LaMnO3 are greatly affected by strong Hund's coupling. Assuming the antiferromagnetic ordering (with a low Neel temperture) along one of the cubic axes, this coupling would result in formation of disconnected ferromagnetic layers. Furthermore, in the presence of the cooperative Jahn–Teller effect the compound becomes a band insulator. At small doping ( La 1-x Ca x MnO 3, x ≪ 1) the band insulator phase coexists with the presence of localized holes. An insulator-ferromagnetic metal transition occurs at the percolation point x c =0.16.

Sintering injection moulded high speed steel to full density at low tempertures : J.Urcola et al. (CEIT-ESII, Spain.)

Traditional ways to obtain homogeneous and efficient skutterudite-based thermoelectric materials usually require long processing time. In this study thermoelectric properties of Se and Te co-doped CoSb3 bulk materials fabricated using a combination of self-propagating high-temperature synthesis and pulse-plasma sintering techniques were investigated. The proposed short-term fabrication route enabled synthesis of thermoelectric materials with high chemical homogeneity. Moreover, simultaneous doping with Se and Te beneficially influenced the electrical and thermal transport properties of the materials. As a result, an ultralow lattice thermal conductivity of 0.86 W m−1 K−1 has been attained while simultaneously doping and filling the voids in the skutterudite structure. The ultralow lattice thermal conductivity could be attributed to the unique lattice dynamics, enhanced point-defect, and electron-phonon scattering. Owing to these synergetic effects, a dimensionless figure of merit of 1.1 was obtained at 723 K. The findings show that combination of self-propagating high-temperature synthesis and pulse-plasma sintering techniques allow to fabricate chemically homogeneous and efficient thermoelectric materials as well as offer numerous advantages, such as time, energy efficiency, and potential scalability, to carry out large-scale production.