Min Soak Research Articles

Fabrication of transparent MgAl 2O 4 spinel polycrystal by spark plasma sintering processing

Transparent spinel can be fabricated without any sintering aids by spark plasma sintering (SPS) processing for only a 20 min soak at 1300 °C. For heating rates

Tonometers and infectious risk: myth or reality? Efficacy of different disinfection regimens on tonometer tips

To evaluate the adequacy of common disinfection regimens for disposable tonometer tips and assess if disinfection of reusable prisms or the use of disposable tips is preferable. We used disposable tonometer tips, using the same material and tip diameter of standard Goldmann tonometer prism. Strains of Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilisand Candida albicanswere tested according to the European standard guidelines for disinfectants test. Antimicrobial effectiveness of the following disinfection practices has been assessed: dry wipe, Minuten wipes (Alpro), soaking in 3% hydrogen peroxide, 0.5% benzalkonium chloride, and 0.5% Pantasept for 1, 5, and 15 min. All tests have been performed three times and all conditions tested in duplicate. Dry wiping and 1 min soak in 3% hydrogen peroxide were ineffective on all microrganisms. Minuten wipes, 1 min soak in 0.5% benzalkonium chloride or 3% hydrogen peroxide were ineffective on B. subtilis. 0.5% Pantasept soak was effective in 1 min for all microrganisms tested, whereas 3% hydrogen peroxide and 0.5% benzalkonium chloride soaks were effective when performed for at least 5 min. B. subtiliswas the most resistant organism to disinfectant regimes at 1 min time. Results of our study demonstrate a relative disinfection efficacy for the different evaluated regimens, provided that correct exposure times are adopted for the chosen disinfectants, a condition difficult to ensure in a busy clinic setting. We conclude that disposable prism tonometry provides a safe alternative to Goldmann tonometry.

Allele Frequencies and Statistic Parameters for Penta D and Penta E Loci in Chinese Han Population

Abstract EDTA whole blood samples were collected from 281 unrelated individuals of Han population living in Wuhan, China. DNA was extracted using Cheles-100 method (1). Hot-start PCR was performed in a total volume of 10 µL containing 10 ng genomic DNA, 0.2 µM each primer, 10 mM Tris-HCl buffer (pH8.3), 50 mM KCl, 1.5 mM MgCl2, 200 µM each dNTP, and 0.3 U Taq DNA polymerase (BioStar, Canada) was add when the temperature reaches 92°C. The primer sequences newly designed by us were: Penta D: 5'-cagagcaagacaccatctcaa-3', 5'-tttgcctaacctatggtcataacg-3'; Penta E: 5'-agatcacgccattgcactcc-3', 5'-gggttattaattgagaaaactccttacaat-3'. PCR cycling conditions: 95°C for 2 min soak, 32 cycles of 30 s at 94°C, 30 s at 62°C for Penta D and 60°C for Penta E, 35 s at 72°C followed by a 5 min extension period at 72°C. The amplification products were separated in a vertical, native polyacrylamide gel (6% T; 5% C) and visualized by silver staining (2). Allele frequencies and other statistics parameters for forensic and paternity were determined for these two locus by the PowerStats software packages (3). The Hardy-Weinberg equilibrium test (HWE) was performed by an exact test (4). None of the analyzed loci showed deviations from HWE (P > 0.05) in the population studied.

Haplotype Distribution of the Multi-copy Y-STR Loci DYS385, DYS459 and DYS464 in Chinese Han Population

Abstract EDTA-blood samples were collected from 176 healthy unrelated males of Han population living in Wuhan, China. DNA was extracted using Cheles-100 method (1). PCR was performed in a total volume of 10 µL containing 2–5 ng genomic DNA, 0.2 µM each primer, 10 mM Tris-HCl buffer (pH 8.3), 50 mM KCl, 1.5 mM MgCl2, 200 µM each dNTP, and 1 U AmpliTaq Gold® DNA polymerase (Applied Biosystems, Foster City, CA). DYS459 and DYS464 were co-amplified in a duplex reaction and DYS385 was amplified in a singleples reaction. Primer sequences: DYS385: 5'-FAM-agcatgggtgacagagcta-3', 5'-gccaattacatagtcctcctttc-3'; DYS459: 5'FAM-caggtgaactggggtaaataat-3', 5'-gttgagcaacagagcaagactta-3'; DYS464: 5'-FAM-ctttgggctatgcctcagttt-3', 5'-gccatacctgggtaacagagagac-3'. PCR cycling conditions: 95°C for 11 min soak, 30 cycles of 40 s at 94°C, 40 s at 60°C, 50 s at 72°C followed by a 6 min extension period at 72°C. All loci were amplified in a GeneAmp PCR System 9700 (PE Applied Biosystems).

Silylation of porous methylsilsesquioxane films in supercritical carbon dioxide

Silylation reactions using a supercritical carbon CO2 solvent were performed on porous methylsilsesquioxane (p-MSQ) thin films. The addition of alkylsilyl moieties to the films repaired damage due to oxygen plasma processing. The films (JSR LKD 5109) were characterized using Fourier transform infrared (FTIR) spectroscopy, ellipsometry, contact angle, and electrical measurements. The silylation chemistries included <1.5 wt% hexamethyldisilazane (HMDS), tetramethyldisilazane (TMDS), and trimethylchlorosilane (TMCS) mixed with supercritical CO2 (scCO2). Blanket films with a dielectric constant of 2.4 before oxygen ashing and 3.5 after ashing were processed at 150–300 atm and 50–60 °C for a 2 min soak time (after a 15 min ramp to steady-state). The disilazanes and chlorosilane reacted with both lone and hydrogen-bonded silanol (SiO–H) groups on the surface of the p-MSQ. The hydrophobicity of the p-MSQ surface was recovered after treatment as shown by contact angles >80°. The dielectric constant of ashed p-MSQ was reduced to 2.5, 3.3, and 2.6±0.1 by HMDS, TMDS, and TMCS addition, respectively. The mechanism proposed involves the direct reaction of the Si-bearing precursor molecules with the p-MSQ surface. Supercritical CO2 is a good solvent for silylation reactions and is an effective approach to restore the degradation of porous MSQ films due to plasma ashing.

Effects of Seed Coat Treatment and Stratification on the Germination Rate of Montezuma Cypress

An experiment was initiated to evaluate the effects of previously recommended seed treatments for baldcypress [Taxodium distichum (L.) Rich.] or pondcypress [Taxodium distichum (L.) Rich. var. imbricarium (Nutt.) Croom] on Montezuma cypress [Taxodium distichum (L.) Rich. var. mexicanum Gordon], and to determine which, if any, provided optimum germination. Factorial combinations of seed treatments and stratification (2 °C for 0, 45, or 90 d) were applied to seeds of Montezuma cypress. Treatments included: 1) 90% ethanol 5 min soak, 2) ethyl ether 5 min soak, 3) 100 mg·L-1 citric acid 48 h soak, 4) mechanical scarification, 5) five hot water baths (42 °C) allowing the water to cool to room temperature between baths, and 6) a non-treated control. Three more seed treatments consisted of water soaks at room temperature (25 °C) for 0, 45, or 90 d. Seeds were germinated on moist filter paper in a growth chamber with a 12-h day/night photoperiod at a constant 25 °C. Data was collected daily for 14 d and then weekly for the following 4 wks. Radicle elongation of 1 cm was considered germination. Without stratification, 100 mg·L-1 citric acid and the hot water bath treatments were significantly different from other treatments by 7 d, though not from each other, with a mean cumulative germination of 15.6% and 12.2%, respectively. By 14 d, the 100 mg·L-1 citric acid treatment differed only from the ethyl ether wash attaining 28.9% and 14.4% germination, respectively. There were no other statistically significant differences observed among any other treatments without stratification. Germination percentages were low,&lt;30%, without stratification. Effects of additional stratification will also be discussed.

Allele Frequencies of Four Short Tandem Repeat Loci in Chinese Han Population

Abstract Genomic DNA was obtained from peripheral blood extracted with Chelex-100 method (1). PCR was performed in a total reaction volume of 20 µL containing 20 ng genomic DNA, 0.2 µM each primer, 10 mM Tris-HCl buffer (pH 8.3), 50 mM KCl, 1.5 mM MgCl2, 200 RM each dNTP, and 1 U Taq DNA polymerase (BioStar, Canada). Primer sequences: D2S1788: 5 -aat gga tgg aca aat gga tg-3, 5 -ccc tcc ata att aga tga gcc-3; D6S1043: 5 -caa gga tgg gtg gat caa ta-3, 5 -ttg tat gag cca ctt ccc at-3; D7S3048: 5 -ctg gag ctg cat agt gtc ct-3, 5 -aat cat ccc tgt gtg ctt tc-3; D12S1064: 5 -act act cca agg ttc cag cc-3, 5 -aat att gac ttt ctc ttg cta ccc-3. PCR conditions: 95°C for 2 min soak, 32 cycles of 35 s at 94°C, 35 s at 60°C, 40 s at 72°C followed by a 5 min extension period at 72°C. The amplification products were separated in a vertical, native polyacrylamide gel (6% T; 5% C) and visualized by silver staining. Allele frequencies and others statistics parameters for forensic and paternity were determined for each locus by the PowerStats software packages (2). The Hardy-Weinberg equilibrium test (HWE) was performed by an exact test (3). None of the analyzed loci showed deviations from HWE (P &amp;gt; 0.05) in the population studied. The complete dataset is available to any interested researcher upon request to the authors.

Low temperature hot-pressed BAS matrix composites reinforced with in situ grown Si 3N 4 whiskers

A series of Si 3N 4/BAS compositions of 20, 40, 60, 80 and 100 wt.% barium aluminosilicate (BAS) were hot-pressed at relatively low sintering temperature (1450 °) for a 30–60 min soak at a pressure of 10–20 MPa under N 2 atmosphere. Elongated rod-like β-Si 3N 4 whiskers were formed for compositions with 20–80 wt.% BAS. No metal ions were dissolved in Si 3N 4 crystal lattices. The microstructure varied with composition. The relative content of rod-like β-Si 3N 4 whiskers increased with increasing BAS content. Densities of all the specimens with BAS contents more than 20 wt.% were >99% of the theoretical density. With a 30 min soak, the room temperature (RT) flexural strength increased from 259.1 to 323.0 MPa from 20 to 40 wt.% BAS and then decreased to 70.6 MPa for 100 wt.% BAS. The fracture toughness increased from 2.40 to 3.24 MPa m 1/2 from 20 to 60 wt.% BAS and then decreased to 1.78 MPa m 1/2 for 100 wt.% BAS. With a 60 min soak, the RT flexural strength of 40 wt.% BAS without monoclinic BAS seeds was 379.6 MPa and retained 87.9, 93.8 and 94.2% of their RT values at 1000, 1100 and 1200 °C, respectively; in contrast, the RT flexural strength of 40 wt% BAS containing 8 wt% BAS seeds was 519.4 MPa and retained 87.3, 63.0 and 51.9% of their RT values at 1000, 1100 and 1200 °C, respectively. Monoclinic BAS seeds had little effect in accelerating the hexagonal→monoclinic phase transformation of BAS glass ceramics.

The effect of toothpaste on the propensity of chlorhexidine and cetyl pyridinium chloride to produce staining in vitro: a possible predictor of inactivation.

Cationic antiseptics such as chlorhexidine (CHX) and cetyl pyridinium chloride (CPC) interact with dietary chromogens to produce extrinsic stain, and this can be used as a measure of activity of products. The aim of these studies in vitro was to determine if toothpaste influenced the tea staining effects of CHX and CPC as a predictor of action in vivo. Clear acrylic specimens were soaked in pooled human saliva followed by sequential 2-min soaks in pairs of agents, namely 0.05% CHX, 0.05% CPC, 0.2% CHX, water (W) and toothpaste slurry (TP). The combinations were; TP/CHX, CHX/TP, TP/CPC, CPC/TP, W/CHX, CHX/W, W/CPC, CPC/W, TP/W, W/TP, W/W. These treatments were followed by a 60 min soak in tea. Optical density readings were taken at baseline and after each of 8 cycles. In the separate CHX and CPC studies by comparison with W/CHX, TP/0.05% CHX had little effect on staining, but TP/0.2% CHX showed a reduction in staining of 18%. 0.05% CHX/TP reduced staining by >40%, and 0.2% CHX by >78%. TP/CPC reduced staining by >26% and CPC/TP by 80%. Water after 0.2% CHX, 0.05% CHX and CPC reduced staining by 18%, 13% and 17% respectively. Little staining was seen with TP and W combinations. The data for CHX are in agreement with a study in vivo except TP followed by CHX reduced the activity of CHX. Toothpaste appears to adversely affect the activity of CHX and CPC particularly if used immediately after the antiseptics. The data further supports the concept of separating the use of antiseptics until sometime after the use of toothpaste, and the idea of developing mouthwash friendly toothpastes.

The effect of toothpaste on the propensity of chlorhexidine and cetyl pyridinium chloride to produce staining in vitro: a possible predictor of inactivation

AbstractBackground/aims: Cationic antiseptics such as chlorhexidine (CHX) and cetyl pyridinium chloride (CPC) interact with dietary chromogens to produce extrinsic stain, and this can be used as a measure of activity of products. The aim of these studies in vitro was to determine if toothpaste influenced the tea staining effects of CHX and CPC as a predictor of action in vivo.Method: Clear acrylic specimens were soaked in pooled human saliva followed by sequential 2‐min soaks in pairs of agents, namely 0.05% CHX, 0.05% CPC, 0.2% CHX, water (W) and toothpaste slurry (TP). The combinations were; TP/CHX, CHX/TP, TP/CPC, CPC/TP, W/CHX, CHX/W, W/CPC, CPC/W, TP/W, W/TP, W/W. These treatments were followed by a 60 min soak in tea. Optical density readings were taken at baseline and after each of 8 cycles.Results: In the separate CHX and CPC studies by comparison with W/CHX, TP/0.05% CHX had little effect on staining, but TP/0.2% CHX showed a reduction in staining of 18%. 0.05% CHX/TP reduced staining by &gt;40%, and 0.2% CHX by &gt;78%. TP/CPC reduced staining by &gt;26% and CPC/TP by 80%. Water after 0.2% CHX, 0.05% CHX and CPC reduced staining by 18%, 13% and 17% respectively. Little staining was seen with TP and W combinations. The data for CHX are in agreement with a study in vivo except TP followed by CHX reduced the activity of CHX.Conclusion: Toothpaste appears to adversely affect the activity of CHX and CPC particularly if used immediately after the antiseptics. The data further supports the concept of separating the use of antiseptics until sometime after the use of toothpaste, and the idea of developing mouthwash friendly toothpastes.

Novel approach to phasing proteins: derivatization by short cryo-soaking with halides.

A quick (less than 1 min) soak of protein crystals in a cryo-solution containing bromide or iodide anions leads to incorporation of these anomalous scatterers into the ordered solvent region around the protein molecules. These halide anions provide a convenient way of phasing through their anomalous scattering signal: bromides using multiwavelength anomalous dispersion (MAD) and bromides and/or iodides using single-wavelength anomalous dispersion (SAD) or single isomorphous replacement with anomalous scattering (SIRAS) methods. This approach has been tested successfully on four different proteins and has been used to solve the structure of a new protein of molecular weight 30 kDa.

DISINFECTION OF SHREDDED SALAD INGREDIENTS WITH SODIUM DICHLOROISOCYANURATE

Raw salads are frequently subjected to hypochlorite wash to reduce microbial numbers, retard enzymatic activity and improve shelf-life of sensory quality. Hypochlorite dips significantly reduce the initial population of natural contaminants on lettuce. However, populations on treated and untreated samples are not significantly different after four days storage at refrigeration temperature. Increasing the level of free available chlorine does not improve the microbicidal effect. In this study sodium dichloroisocyanurate (NaDCC) was used to disinfect salad vegetables. Though the principal salad vegetable used was butterhead lettuce, results show that the efficacy of NaDCC in reducing total aerobic mesophile levels varies with vegetable type. NaDCC gives an acid pH in solution and has significantly higher activity than sodium hypochlorite. For longer term storage, preparation of lettuce which included a 30 min soak in NaDCC improved the microbiological quality of the produce at the end of the storage period. The microbial load on disinfected produce was between 0.62 and 0.98 log cycles lower than on lettuce prepared without a disinfection step for up

A Field and Storage Rot of Onion (Allium cepa L. var. cepa) Caused by Pseudomonas cepacia in Lowland Papua New Guinea

AbstractA bacterium consistently isolated from rotting onions in the field and in storage was shown by biochemical and pathogenicity tests to be Pseudomonas cepacia. In experiments to determine the mode of entry of the pathogen only injured bulbs developed a soft rot after a 10 min soak in a suspension of P. cepacia (approx. 108 cfu/ml).

Geometrical factors of argon incorporation in SiO 2 films deposited by ion beam sputtering

The geometrical conditions for argon incorporation in SiO 2 films prepared by ion beam sputter deposition were studied experimentally. The main factor was the ejection angular dependence of the incorporated argon from the fused silica target, which was found to be quite different from that of sputtered particles such as silicon. By a judicious choice of the ejection angle and the angle of incidence of the ion beam to the target, it was found that sputter depositions with amounts of incorporated argon differing by a factor of 10 can be achived under the same deposition rate. An immersion test in a 10% aqueous solution of NaOH maintained at 70°C revealed that the SiO 2 film deposited onto an Si(100) substrate under conditions of low argon incorporation flaked off within several minutes, while the sample with a high incorporation of argon showed good adhesion even after a 40 min soak. The results indicated that the conventional idea that ion beam sputter deposition yields films with good adhesion to the substrate and a low incorporation of impurities is not generally valid; instead these characteristics depend markedly on the geometrical conditions of deposition.

Removal of zinc residues from apple leaves by hydrochloric acid and leaching of other nutrients in the process

AbstractLeaves sampled from “Lord Lambourne”, “Starking Delicious” and “Golden Delicious” apple trees sprayed with zinc sulphate were treated in various ways (a detergent wash, an acid wash, a 10 min, or a 20 min soak in N‐HCl). Leaves which were soaked had the lowest zinc content, and this was attributed to “internal” zinc; the other treatments left behind more zinc, and the increase was attributed to “external” and/or easily leachable zinc. A single spray (0.3% ZnSO4. H2O) increased “internal” zinc contents to ∼50 parts/106, and three sprays to ∼150 Parts/106. Soaking the leaves in N‐HCl for 10 min leached out K, Mg and Mn but not N, P or Fe. As with zinc, soaking for 20 min did not, except in one case, leach out any additional amounts of nutrients. It is suggested that there may be an “easily leachable” fraction of K, Mg, Mn, and possibly Zn, which is removed from the leaves by the 10 min soak in N‐HCl.

The effect of calcium on the force-velocity relation of briefly glycerinated frog muscle fibres.

1. Twitch fibres were isolated from the semitendinosus muscles of frogs. The sarcolemma was made more permeable by a 30 min soak in a solution containing 47.3% glycerine (v/v), 2 mM-EGTA and 10 mM phosphate buffer, pH 7. This was followed by a 30-60 min soak in a solution containing the non-ionic detergent Lubrol-WX. The fibres were then placed in a relaxing medium containing (in mM): KCl, 100; MgCl(2), 1; ATP, 4; EGTA, 2; imidazole buffer, 10; pH 7.0.2. A piece of fibre about 1-2 mm long treated as described in (1) was attached to a servo apparatus. This apparatus made it possible either to hold fibre length constant giving isometric conditions, or alternatively to hold the force constant while measuring isotonic length changes. A special network made it possible to switch control from isometric to isotonic conditions so that afterloaded contractions with a shortening stop could be carried out.3. Contractions were induced at about 4 degrees C by lowering the pCa in the relaxing solution to various levels determined by the ratio of calcium and EGTA added. Contractions were never observed above pCa 7. The steady force generated reached a maximum over the range of pCa 6.09 to 5.49. The relationship between steady force generated and pCa is S-shaped and very steep, implying that multiple interacting binding sites for calcium are involved in the force generating process.4. The relative force-velocity relation is the same at pCa 6.09 and 5.49 where the steady force is at a maximum. The data points can be well fitted by a hyperbola in which the extrapolated value for V(max) is 2.39 muscle lengths/sec. The values obtained for the Hill parameters a/P(0) and b are within the range of those reported for living electrically excited frog muscle.5. The relative force-velocity points obtained at higher pCa values at which the steady force was on average 37% of that developed at pCa 5.49 can also be fitted by a hyperbola. However, the extrapolated value for V(max) is only 1.12 muscle lengths/sec. The value for a/P(0) is increased slightly and the value for b is markedly decreased.6. Evidence is presented against the possibility that an unrecognized fixed internal load is responsible for the change in the relative force-velocity relation obtained at high pCa.7. The relative force-velocity relation does not change appreciably over at least part of the range of sarcomere lengths in which the force generated varies linearly with overlap provided the pCa is held constant.8. The results support the view that lowering the pCa produces a mechanical state equivalent to that produced by tetanic electrical stimulation.9. Some models for calcium activation are discussed. It is concluded that a model based on calcium binding to troponin on the thin filaments is difficult to reconcile with all of the experimental evidence. There is additional evidence for believing that activating calcium may directly influence the cross-bridges.

Stain Technology: A Phenylhydrazine-Leucofuchsin Sequence for Staining Nerves and Nerve Endings in the Integument of Poultry

This sequence for staining cutaneous nerves and nerve endings uses 1% formic acid as a fixative for 1 hr, followed by two treatments of 5 min each in 6% H2SO4. The tissue is then submerged in fresh 5% phenylhydrazine hydrochloride for 30 min, washed in running tap water for 10 min, and given a 5 min soak in distilled water. The specimen is placed in Lillie's “cold Schiff” reagent for 4 hr; transferred to 6% H2SO4, 4 changes of 5 min each; washed in distilled water, 3 changes of 5 min each; dehydrated in acetone, 4 changes of 10 min each; and cleared in 2 changes of methyl benzoate, the 1st for 1 hr and the 2nd until the tissue clears. Nerve fibers stain pinkish-purple; muscles also take up the stain, yet the nerves are discernible from the muscles. All other tissue remain unstained.