Dependence of Lower Molding Temperature Limit and Molding Time on Molding Mechanism in Dental Thermoforming

Effectiveness and safety of a sports mouthguard depend on its thickness and material, and the thermoforming process affects these. The purpose of this study was to clarify the effects of differences in molding mechanisms on the lower molding temperature limit and molding time in dental thermoforming. Ethylene vinyl acetate resin mouthguard sheet and two thermoforming machines;vacuum blower molding machine and vacuum ejector/pressure molding machine were used. The molding pressures for suction molding were −0.018 MPa for vacuum blower molding and −0.090 MPa for vacuum ejector molding, and for pressure molding was set to 0.090 MPa or 0.450 MPa. Based on the manufacturer’s standard molding temperature of 95˚C, the molding temperature was lowered in 2.5˚C increments to determine the lower molding temperature limit at which no molding defects occurred. In order to investigate the difference in molding time depending on the molding mechanism, the duration of molding pressure was adjusted in each molding machine, and the molding time required to obtain a sample without molding defects was measured. The molding time of each molding machine were compared using one-way analysis of variance. The lower molding temperature limit was 90.0˚C for the vacuum blower machine, 77.5˚C for the vacuum ejector machine, 77.5˚C for the pressure molding machine at 0.090 MPa, and 67.5˚C for the pressure molding machine at 0.45 MPa. The lower molding temperature limit was higher for lower absolute values of molding pressure. The molding time was shorter for pressure molding than for suction molding. Significant differences were observed between all conditions except between the pressure molding machine at 0.090 MPa and 0.45 MPa (P < 0.01). A comparison of the differences in lower molding temperature limit and molding time due to molding mechanisms in dental thermoforming revealed that the lower molding temperature limit depends on the molding pressure and that the molding time is longer for suction molding than for pressure molding.

Effects of temperatures on the development and reproduction of the armyworm, Mythimna roseilinea: Analysis using an age-stage, two-sex life table

The armyworm Mythimna roseilinea（Walker） is a major pest of grain crops in South China. So far little is known about its basic biology and ecology, making prediction of population dynamics difficult. This study examined the relationships of individual development and population growth with temperature based on an age-stage, two-sex life table of M. roseilinea reared on maize in the laboratory at 18, 21, 24, 27 and 30℃. The highest values of net reproductive rate（R_0） and fecundity were observed at 21 and 24℃, respectively. Both the intrinsic rate of increase（r） and finite rate of increase（λ） increased significantly and mean generation time（T） decreased significantly with increasing temperature. M. roseilinea was able to develop, survive and lay eggs at all temperature regimes tested. Development rates of the egg, larval, pupal, as well as the whole pre-oviposition stages had a positive linear relationship with temperature. The calculated development threshold temperatures of egg, larval, pupal, pre-oviposition and total pre-oviposition stages were 13.29, 8.39, 14.35, 7.42, and 12.24℃, respectively, and their effective accumulated temperatures were 63.59, 445.00, 211.11, 89.02, and 698.95 degree-days, respectively. These results provide insight into temperature-based phenology and population ecology of this insect pest and will allow population prediction and management available in the field.

Synthesis and Characterization of Liquid Crystal with Lower Temperature of Phase Change of meso-tetra-(4-n-lauroyloxyphenyl)porphyrin

The synthesis and characterization of meso-tetra (4-n-lauroyloxy phenyl) porphyrin with long ester chains are reported. The domains of stability and the structure of the liquid crystalline phases are determined by optical microscopy and differential scanning calorimerials (DSC).

Alumina Solubility in Na_3AlF_6-K_3AlF_6-AlF_3 Molten Salt System Prospective for Aluminum Electrolysis at Lower Temperature

The alumina solubility in the title system within the composition range of KR{m（K3AlF6）/[m（K3AlF6）＋ m（Na3AlF6）]} 10%―50%, a ternary Na3AlF6-K3AlF6-AlF3 molten system with 23%―29%（mass fraction） AlF3 was investigated by measuring the mass loss of a rotating sintered corundum disc. And the following empirical equation was derived when superheat degree was no more than 60 °C： w（Al2O3）sat=A×（T/1000）B, where A= –1.85774＋ 26.754234w（AlF3）–0.3683–0.00783KR2.363＋0.010266KR2.3048＋0.7902w（AlF3）0.00652, B=112.4625–53.2567w（AlF3）0.4236＋ 5.1079w（AlF3）0.9241＋0.01542w（AlF3）1.3540. Considering both higher alumina solubility and not too high superheat de gree are required, alumina solubility of different compositions at not the same temperature but the same superheat degree was studied, which will be more industrial helpful for selecting prospective compositions. The results show that the composition deserved to be further tested in lower temperature cells is 10%―30% KR and 23%―26%（mass fraction） AlF3.

A New Weighting Function for Estimating Microwave Sounding Unit Channel 4 Temperature Trends Simulated by CMIP5 Climate Models

A new static microwave sounding unit （MSU） channel 4 weighting function is obtained from using Coupled Model Inter-comparison Project, Phase 5 （CMIP5） historical multimodel simulations as inputs into the fast Radiative Transfer Model for TOVS （RTTOV v10）. For the same CMIP5 model simulations, it is demonstrated that the computed MSU channel 4 brightness temperature （T4） trends in the lower stratosphere over both the globe and the tropics using the proposed weighting function are equivalent to those calculated by RTTOV, but show more cooling than those computed using the traditional UAH （University of Alabama at Huntsville） or RSS （Remote Sensing Systems in Santa Rosa, California） static weighting functions. The new static weighting function not only reduces the computational cost, but also reveals reasons why trends using a radiative transfer model are different from those using a traditional static weighting function. This study also shows that CMIP5 model simulated T4 trends using the traditional UAH or RSS static weighting functions show less cooling than satellite observations over the globe and the tropics. Although not completely removed, this difference can be reduced using the proposed weighting function to some extent, especially over the tropics. This work aims to explore the reasons for the trend differences and to see to what extent they are related to the inaccurate weighting functions. This would also help distinguish other sources for trend errors and thus better understand the climate change in the lower stratosphere.

Effects of Lower Temperature in Spring on Tea Yield in Xuancheng Area

Data of daily mean temperature, precipitation, sunshine hours and tea yield in Xuancheng area from 1979 to 2008 were used to analyze the relationship between lower temperature in spring and tea yield. The results showed during 1979 -2008, the per unit area yield of tea in Xu- ancheng area fluctuated greatly in various years. The relative meteorological yield of tea changed greatly during 1979 -2008, and the decrease in tea yield occurred frequently over the past 30 years. Over the past 30 years, the probability of lower temperature in spring was 56.7%, and the probability of serious and extremely serious lower temperature in spring was 43.4%. In each off year with decrease in tea yield, medium or above lower temperature in spring occurred, showing that the impact of lower temperature in spring on tea yield was very obvious.

Behavior of HSLA A709 Steel under Different Environmental Conditions

According to the requirement of the knowledge of material mechanical properties in structure design procedure,the paper considered experimentally obtained data regarding the high-strength low-alloy A 709 Gr50 steel.In that way,ultimate tensile strength and 0.2 offset yield strength at both lowered and elevated temperatures were presented and analyzed.The effect of temperature exerted on both of the mentioned strengths was presented.Creep responses for selected temperatures and selected stress levels were also considered.All of the tests are related to the uniaxial tensile tests and were performed in the laboratory of the Department for Engineering Mechanics at the Faculty of Engineering Rijeka.

Co-firing of LNT/Ag Multilayer Sheets Prepared by Aqueous Tape Casting

Multilayer ceramic sheets composed of Li1.075Nb0.625Ti0.45O3 （LNT） layers and silver metal layers were fabricated by aqueous tape-casting method. LNT green tape was prepared using PVA （polyvinyl alcohol） as binder and ethylene glycol as plasticizer. The influence of the slurry composition on the rheological properties of the slurries and the properties of the resultant green tapes were studied. The slurry exhibited a typical shear thinning behavior. The increase in the PVA content increased the tensile strength of the tapes. The slip compositions with 5 wt pct PVA produced green tapes with satisfactory tensile strength. Ethylene glycol additions enhanced the flexibility of the green tapes but also produced a decrease in the tensile strength. Sliver inner-electrode was pasted on LNT green tapes and the sheets were stacked, pressed and sintered at 900℃ for 2 h. SEM （scanning electron microscopy） micrographs showed that the multilayer sheets were fully dense with fairly uniform microstructure and no reaction was observed between LNT and sliver layers.

Synthesis and Properties of Poly (N-isopropylacrylamide) and Poly (N-isopropylacrylamide-co-acrylamide) Hydrogels

The thermosensitive poly （ N-isopropylacrylamide ） （PNIPAAm） and poly （N-isopropylacrylamide-co-acrylamide） [ poly （NIPAAm-co-AAm） ] hydrogels with different acrylamide molar percentage are prepared by radiation polymerization using Co^60 γ-ray. Their swelling equilibrium data in the media of deionized water, NaCl aqueous solutions and different pH buffer solutions are determined. It appears that lower critical solution temperature （LCST） of the hydrogels will drop with the increase of ionic strength and increase with the rising of acrylamide content, A semi-empirical formula is set up with the experimental results. Moreover, it also indicates that this copolymer is pH-sensitive, which is similar to the homopolymer of PNIPAAm.

Temperature/pH dual-responsive reversible morphology evolution of block copolymer microparticles under three-dimensional confinement

Development of block copolymer(BCP)microparticles with switchable morphology in response to external stimuli is important for exploiting new intelligent materials.In this work,thermo/p H dual-responsive nanoparticles(NPs)were employed as a cosurfactant to modulate the self-assembly morphology of polystyrene-b-poly(2-vinylpyridine)(PS-b-P2VP)microparticles within confined emulsion droplets.The co-surfactant was synthesized by grafting poly(acrylic acid)-b-poly(N-isopropylacrylamide)onto the surface of Fe3O4NP.The introduction of the dual-responsive co-surfactant enabled thermo/p H dual-responsive reversible morphology transition of the PS-b-P2VP microparticles by tailoring the hydrophobicity and interfacial affinity of the cosurfactant.By using this strategy,the thermo-inert PS-b-P2VP self-assembled into pupa-like microparticles at T=10℃ and p H7.5,which could transform into tulip-like microparticles when T was increased to 50℃.When the p H value was increased to 11,the pupa-like particles turned into onion-like microparticles although the PS-b-P2VP was inert to alkali.However,the pupa-like microparticles remained unchanged when both T and p H were simultaneously increased.The PAA-b-PNIPAM-grafted Fe3O4NP surfactants showed obvious advantages over the linear PAA-b-PNIPAM surfactants in modulating the morphology transition,since the linear PAA-b-PNIPAM could not induce the reversible shape transition of microparticles.Our work provides an efficient strategy to achieve reversible shape transformation of BCP microparticles while the internal phase structure is preserved,which may be utilized to switch the structural color properties of BCP microparticles.

Non-invasive prenatal molecular detection of a fetal point mutation for congenital adrenal hyperplasia using co-amplification at lower denaturation temperature PCR

Conventional prenatal diagnosis relies on invasive chorionic biopsy or amniocentesis, which increases the risk of miscarriage, and is undertaken at 11-20 weeks gestation.1 The discovery of cell-free fetal DNA in maternal plasma has, however, offered a new strategy for non-invasive prenatal diagnosis.2 Cell-free fetal DNA in maternal plasma has been used for the determination of fetal gender3 and RHD status4 as well as testing certain monogenic diseases such as 13-thalassemia5 and cystic fibrosis.6 However,

Controlling the gelation temperature of biomimetic polyisocyanides

Thermosensitive polymers show an entropy-driven transition from a well-solvated to a poorly solvated polymer chain, resulting in a more compact globular conformation. The transition at the lower critical solution temperature（LCST） is often sharp, which allows for a wide range of smart material applications.At the LCST, oligo（ethylene glycol）-substituted polyisocyanides（PICs） form soft hydrogels, composed of polymer bundles similar to biological gels, such as actin, fibrin and intermediate filaments. Here, we show that the LCST of PICs strongly depends linearly on the length of the ethylene glycol（EG） tails; every EG group increases the LCSTand thus the gelation temperature by nearly 30 ℃. Using a copolymerisation approach, we demonstrate that we can precisely tailor the gelation temperature between 10 ℃ and 60 ℃and, consequently, tune the mechanical properties of the PIC gels.

Supramolecular control over thermo-responsive systems with lower critical solution temperature behavior

Lower critical solution temperature(LCST)is the critical temperature below which the solution is miscible for all compositions and above which the solution becomes a suspension.The study of LCST properties has become a central research topic due to its profound impact on the applications of stimuli-responsive materials.Inspired by the marriage between materials science and supramolecular chemistry,the introduction of supramolecular pairs and interactions into polymeric LCST systems is increasingly practiced.Especially,supramolecular interactions provide precise control over LCST behavior in both water and organic solvents.Furthermore,supramolecular interactions not only control or adjust LCST behavior(supramolecular interaction controlled LCST),but also induce LCST phase behavior in species lack of thermo-sensitive properties(supramolecular interaction induced LCST).In this review,we summarize the applications of supramolecular interactions in LCST systems.By examining the relationship between supramolecular interactions and LCST changes,we further discuss the differences between supramolecular interaction controlled LCST and supramolecular interaction induced LCST.We hope this review will give our readers a snapshot on how the supramolecular interactions influence the LCST behavior in various systems,and benefit them with different applications.

Tunable LCST-type phase behavior of [FeCl4]--based ionic liquids in water

In this work, 16 kinds of [FeCl4]--based magnetic ionic liquids （ILs） with different cation structures have been designed and synthesized, and their structures are characterized by IR and Raman spectroscopy. Then the lower critical solution temperature （LCST）-type phase behavior of these magnetic ILs in water is investigated as a function of concentration. It is shown that cat- ion structure, alkyl chain length and molar ratio of FeCl3/chloride IL have a significant influence on the LCST of the mixtures. The phase separation temperature can be tuned efficiently by these factors. Meanwhile, the LCST-type phase separation pro- cess is also investigated by dynamic light scattering. The results support the mechanism that the hydrogen bonds of the [Fefl4]- anion with water have been gradually disrupted to form ILs aggregates with increasing temperature. In addition, the stability of the ILs in water is also examined in some details. These LCST-type phase separation systems may have potential applications in extraction and separation techniques at room temperature.

Micromechanical properties of poly(N-isopropylacrylamide)hydrogel microspheres determined using a simple method

Temperature-responsive poly（N-isopropylacrylamide） （PNIPAM） hydrogel microspheres have attracted extensive attention because of their promising diverse biomedical applications. A quantitative understanding of the micromechanical properties of these microspheres is essential for their practical application. Here, we report a simple method for the characterization of the elastic properties of PNIPAM hydrogel microspheres. The results show that PNIPAM hydrogel microspheres exhibit elastic deformation and the obtained force-deformation experimental data fits the Hertz theory well. The moduli of elasticity of the PNIPAM hydrogel microspheres prepared under different conditions were systematically investigated in this work for the first time. The PN1PAM hydrogel microsphere composition significantly affects their micromechanical properties and their temperature sensitivity behavior. PNIPAM hydrogel microspheres with a larger equilibrium volume change have a lower modulus of elasticity. The modulus of elasticity of the PNIPAM hydrogel microspheres at body temperature （37 ℃, above the lower critical solution temperature （LCST） of PNIPAM） is much higher than that at room temperature （25 ℃, below the LCST of PNIPAM） because ofthermo-induced volume shrinkage and an increase in stiffness. These results provide valuable guidance for the design of smart materials for practical biomedical applications. Moreover, the simple microcompression method presented here also provides a versatile way to investigate the micromechanical properties of microscopic biomedical materials.

Supramolecular control over LCST behavior of hybrid macrocyclic system based on pillar[5]arene and crown ether

A hybrid system containing a pillar[5]arene unit and ten crown ether moieties was developed.The LCST behavior and thermo-responsive ness were successfully introduced into this pillar[5]arene-crown ether system.Both host-guest interactions and salting-out effect displayed great effects in realizing the supramolecular control over LCST properties and the rmo-re sponsiveness.Compa red with the individual macrocycles,this hybrid macrocycle system dramatically amplified the supramolecular control effect over LCST behavior.