Pull-down Test Research Articles

Retrofit assessment of refrigerator using hydrocarbon refrigerants

This study used hydrocarbon (HC) refrigerants in a small R134a refrigerator to evaluate the refrigeration performance and feasibility of using these alternative refrigerants by conducting the no-load pull-down test and 24-hour on-load cycling test. The mixed mass ratios of the HC refrigerants, R290 and R600a, were 65% and 35% (HC1), 50% and 50% (HC2), and 0% and 100% (HC3), respectively. The charged ratios were 30%, 40%, 50%, and 60% based on the charged mass of R134a for HC refrigerants. The results of the no-load pull-down test revealed that the optimal charged mass for all the HC refrigerants was 40% of that of R134a. Most of the experimental results of the HC refrigerators obtained using the optimal charged masses showed that freezer temperature and power consumption were higher than those of the R134a refrigerator. Therefore, the capillary tube lengths of R134a, HC1, HC2, and HC3 were recalculated to be 2.77, 5.05, 5.34, and 5.60 m, respectively, and the recalculated capillary tube was used in the 24-hour on-load cycling test. The results of the 24-hour on-load cycling test showed that the freezer temperatures considerably decreased when the HC refrigerants were used, and that all of the HC refrigerants could be used in the R134a refrigerator after changing the capillary tube lengths. All of the HCs refrigerants yielded lower electricity consumption, lower on-time ratios, and higher energy factors (EFs) than R134a did. The EFs of HC1, HC2, and HC3 were 9.1%, 12.2%, and 42.3% higher than that of R134a, respectively. Using a higher proportion of R600a in HC refrigerants can enhance the EFs of refrigerators.

HFO-1234yf를 적용한 가정용 냉동/냉장고의 성능평가

The performance of HFO-1234yf as a substitute for R-134a was evaluated in a household freezer/refrigerator. A series of tests such as 'refrigerant charging test, pull-down test, cooling speed test, and energy consumption test were carried out under the AHAM (Association of Home Appliance Manufacturers) standard. The results of a drop-in test were compared with those of a test conducted using R-134a. A test under a severe ambient air condition () was also conducted. The result shows that the refrigeration cycle performance of HFO-1234yf is as good as that of R-134a ; however, the diameter of capillary tube should be increased in order to improve its performance in the cooling speed test.

Effects of K-ras gene mutation on colon cancer cell line Caco-2 metastasis by regulating E-cadherin/beta-catenin/p120 protein complex formation and RhoA protein activity

To explore the effects of K-ras gene mutation on colon cancer cell line Caco-2 metastasis by regulating E-cadherin/beta-catenin/p120 protein complex formation and RhoA protein activity. K-ras wild-type colon cancer cell line Caco-2 was transiently transfected by phr-GFP vector (control group), transfected by mutant K-ras gene phr-K-ras (Val12) vector (transfection group), transfected by mutant K-ras gene phr-K-ras (Val12) vector and treated by specific MAPK pathway inhibitor PD98059 (MAPK inhibition group), or transfected by mutant K-ras gene phr-K-ras (Val12) vector and treated by specific PI-3K pathway inhibitor LY294002 (PI-3K inhibition group), respectively. Cell migration was tested by Transwell experiment. E-cadherin and beta-catenin protein expression and intracellular location were detected by cell immunofluorescence method. Intracellular p120 protein expression was detected by Western blot. beta-catenin protein level which combined with E-cadherin was detected by immunoprecipitation. RhoA activity was analyzed by Pull-down assay. The Caco-2 cell migration rate was (19.8 +/- 5.6) % in transfection group, which was significantly higher than that in control group [(14.0 +/- 4.2) %] (P = 0.001) and in MAPK inhibition group [(15.8 +/- 1.2) %] (P = 0.044), but was not significantly different from that in PI-3K inhibition group [(17.5 +/- 2.8) %] (P = 0.095). Immunofluorescence method showed that the E-cadherin and beta-catenin stain located in the cell membrane decreased in transfection group. Western blot showed that the total intracellular p120 protein decreased in transfection group and PI-3K inhibition group. Immunoprecipitation data showed that beta-catenin protein level combined with E-cadherin decreased in transfection group and PI-3K group. Pull-down test showed that RhoA protein activity was up-regulated in transfection group. K-ras gene mutation stimulates the migration of colon cancer cell Caco-2, which may be achieved by decreasing the E-cadherin/beta-catenin/p120 protein complex formation via MAPK pathway and increasing the RhoA protein activity.

Optimisation of visi cooler with the low global warming potential refrigerant mixture as an alternative to R134a and HC blend

In this study, the performance of a visi cooler has been evaluated by using the ternary mixture of R134a/R290/R600a with five different mass fractions as an alternative to R134a and HC mixture. Baseline tests have been carried out with R134a and HC mixture and the performance parameters were compared with the five selected alternative refrigerant mixtures. The performance is optimised by varying the refrigerant charge and capillary tube length under experimental conditions for both the pull-down test and the energy consumption test. The optimised refrigerant charge of the ternary mixture is approximately 50% of that of the optimised R134a system and the global warming effects will be decreased by two-thirds. The cooling speed is increased by 25% and COP is increased by 9.9%. The length of the capillary is increased by 63.63% to obtain the best performance. The agreement between the predicted values and experimental values is found to be satisfactory.

Performance characteristics of a small-capacity directly cooled refrigerator using R290/R600a (55/45)

In this study, the performance of a small-capacity directly cooled refrigerator was evaluated by using the mixture of R290 and R600a with mass fraction of 55:45 as an alternative to R134a. The compressor displacement volume of the alternative system with R290/R600a (55/45) was modified from that of the original system with R134a to match the refrigeration capacity. Both systems with R290/R600a (55/45) and R134a were tested, and then optimized by varying the refrigerant charge and capillary tube length under experimental conditions for both the pull-down test and the power consumption test. The refrigerant charge of the optimized R290/R600a system was approximately 50% of that of the optimized R134a system. The capillary tube lengths for each evaporator in the optimized R290/R600a system were 500 mm longer than those in the optimized R134a system. The power consumption of the optimized R134a system was 12.3% higher than that of the optimized R290/R600a system. The cooling speed of the optimized R290/R600a (55/45) system at the in-case setting temperature of −15 °C was improved by 28.8% over that of the optimized R134a system.

Protein-protein Interaction Between Domains of PDZ and BAR from PICK1

Two DNA fragments encoding PDZ domain(21–110 residues) and BAR domain(150–360 residues) from PICK1 (1–416 residues) were amplified by PCR and then introduced into vectors, pET-32M and pMAL-c2X respectively to generate recombinant plasmids, pE-pdz and pM-bar. Having been separately transferred into the hosts E. coli BL21 and E. coli JM109, these two strains can express fusion proteins: His-tagged PDZ(PDZ domain) and maltose binding protein-BAR(MBP-BAR domain) respectively, as confirmed by both SDS-PAGE and Western blotting. The interaction between these two domains is dose-dependence, as identified by a pull-down test. Moreover, it has been shown from the ELISA analysis that the actual amount of PDZ bound to MBP-BAR-amylose beads reaches (16 ± 0.5)%, as calculated by the molar ratio of PDZ to MBP-BAR. In addition, the interaction between BAR(bait) and PDZ(prey) in vivo was also examined with a yeast two-hybrid system.

Is the Presidentʼs Challenge a Valid Test of Fitness in Children Ages 10-14?

Childhood obesity is increasingly becoming a public health concern. The CDC has reported that approximately 25% of children in the United States are overweight and 11% are obese. Increasing childhood fitness is one way in which childhood obesity can be conquered and fitness testing is currently used to determine physical fitness levels in children. However, the validity of physical fitness testing in children has been immersed in controversy for over 30 years. PURPOSE: To determine if the President's Challenge is a valid predictor of physical fitness in children between 10 and 14 years of age. METHODS: Twenty three subjects, between the ages of 10 and 14, completed two fitness testing protocols. Protocol one was the President's Challenge and protocol two was developed by the researchers at the University ofEvansville (UE) entitled the UE Protocol. The President's Challenge consisted of a one-mile endurance run/walk, a shuttle run, curl-ups, pull-ups, and a sit and reach test. The UE Protocol consisted of measuring VO2 peak with a metabolic cart, using the Bruininks-Oseretsky protocol subtest 1, abdominal strength test using a Lafayette Manual Muscle Test System (MMT), pull-down test using a Base Line hydraulic push-pull dynamometer, Modified-Modified Schober Technique, and a 90/90 Test for hamstring flexibility. An intraclass correlation coefficient model (3, 1) was performed to analyze data. RESULTS: The ICC(3,1) between the President's Challenge shuttle run and the Bruininks-Oseretsky protocol subtest 1 was found to be 0.728. The ICC(3,1) between the Sit & Reach and the Modified-Modified Schober Technique was found to be 0.020. The ICC(3,1) between the Sit & Reach and both hamstring flexibility tests was found to be −0.107. The ICC(3,1) between the four tests was found to be −0.075. The ICC(3,1) between pull-ups and the pull-down test was found to be 0.117. The ICC(3,1) between curl-ups and the abdominal strength test was found to be 0.305. CONCLUSION: The components of the President's Challenge were not found to be a valid means of testing physical fitness in children ages 10–14.

Intratester Reliability for Determining an 8-Repetition Maximum for 3 Shoulder Exercises Using Elastic Bands

Context:Standardization of training load using the 1-repetition maximum (1RM) test cannot be directly applied when using elastic bands as resistance.Objective:To determine the intratester reliability for establishing an 8-repetition maximum (8RM) using elastic bands.Design:Test–retest.Participants:5 men, 10 women, 23–29 years.Intervention:An 8RM test was established for 3 shoulder exercises using the Dura-Band® exercise system.Main Outcome Measures:The length of the elastic band was recorded. An analysis of variance was performed, and intraclass correlation coefficients (ICC) were calculated for each exercise.Results:Intratester reliability for determining the elastic-band length required to establish an 8RM was very high for internal rotation (ICC = .91) and high for external rotation (ICC = .77). The diagonal pull-down 8RM test had moderate reliability (ICC = .65).Conclusion:Training load can be reliably standardized in healthy young adults using moderate-to high-resistance elastic bands with a goal-based multiple-RM test.

HTRP--An Immediate-Early Gene Product Induced by HSV1 Infection in Human Embryo Fibroblasts, Is Involved in Cellular Co-Repressors

The interaction between virus and receptor is a process that mimics physiological ligand binding receptors and induces signal transduction. In the investigation of the interaction between HSV1 (Herpes Simplex virus 1) and human fibroblasts via virus binding to its receptor complex on cellular membranes, the HTRP (human transcription regulator protein), a protein encoded by an immediate-early gene of cellular response against the specific stimulation of HSV1 binding, was cloned from a cDNA library established from early gene response mRNA. The localization of HTRP expressed as a fusion polypeptide with a fluorescent protein in HeLa cells was confirmed to be the nucleus. The results of a yeast two-hybrid experiment indicated that HTRP is indeed involved in the interaction with the SAP (mSin3-associate polypeptide) complex via SAP30. A pull-down test and Western blotting in vitro, and immunoprecipitation in vivo also provided evidence in support of this result. The interaction of HTRP with SAP30 in its conserved domain implies that this protein family, as the products of immediate-early genes, comprise functional molecules involved in the transcriptional regulation of cells, which might be related to the inhibition of some cell survival genes.

Testing of propane/isobutane mixture in domestic refrigerators

The performance of a propane/isobutane (R290/R600a) mixture was examined for domestic refrigerators. A thermodynamic cycle analysis indicated that the propane/isobutane mixture in the composition range of 0.2 to 0.6 mass fraction of propane yields an increase in the coefficient of performance (COP) of up to 2.3% as compared to CFC12. For the actual tests, two commercial refrigerators of 299 and 465 l were used. For both units, all refrigeration components remained the same throughout the tests, except that the length of the capillary tube and amount of charge were changed for the mixture. Each refrigerator was fully instrumented with more than 20 thermocouples, two pressure transducers, and a digital watt/watt-h meter. For each unit, both ‘energy consumption test’ and ‘no load pull-down test’ were conducted under the same condition. The experimental results obtained with the same compressor indicated that the propane/isobutane mixture at 0.6 mass fraction of propane has a 3–4% higher energy efficiency and a somewhat faster cooling rate than CFC12. The mixture showed a shorter compressor on-time and lower compressor dome temperatures than CFC12. In conclusion, the proposed hydrocarbon mixture seems to be an appropriate long term candidate to replace CFC12/HFC134a from the viewpoint of energy conservation requiring minimal changes in the existing refrigerators.