Noble gases of Yamato 980459 shergottite

Isotopic ratios and concentrations of noble gases were determined for the Yamato (Y) 980459 olivine-phyric shergottite with a stepped heating extraction method. Trapped noble gas concentrations are low, and especially He and Ne are dominated by cosmogenic nuclides. Heavy noble gases, Ar, Kr and Xe, in the high temperature fractions (1000-1750°C ) show the martian atmospheric signatures: 40Ar36Ar and 129Xe132Xe ratios corrected for cosmogenic gases are >1000 and >1.4, respectively, and the data points plot along the mixing line between the Mars atmosphere and Chassigny in the system of 129Xe132Xe vs. 84Kr132Xe. Contribution of elementally fractionated Earth\u27s atmospheric noble gases is significant in the low temperature fractions (400-800°C ), which has been frequently reported for meteorites from hot deserts. Cosmic-ray exposure ages calculated based on cosmogenic 3He, 21Ne and 38Ar are 1.6, 2.5 and 2.1Ma, respectively. Considering partial loss of He from the meteorite, the exposure age of Y980459 would be around 2.1-2.5Ma. Though the terrestrial age of this meteorite has not been reported so far, the ages reported for Antarctic SNCs are 0.29Ma. Hence, the ejection age for Y980459 could be in the range of 2.1-2.8Ma, which is comparable to those of some basaltic shergottites, but different from other olivine-phyric shergottites ranging mostly 0.7-1.2Ma. Isotopic ratios of Kr show excesses in 80Kr and 82Kr, with 82Kr80Kr of 0.375, which results from epithermal neutron captures on 79Br and 81Br. The minimum pre-atmospheric size of Y980459 was calculated as 27cm in radius, based on the 21Ne exposure age and the n-capture 80Kr and Br concentrations of 3.0×1013cm3STPg and 0.205ppm, respectively. The calculated K-Ar age is 0.99Ga from the total 40Ar and reported K concentration of 157ppm. The age, however, gives an upper limit for the crystallization age of this meteorite, because of possible contribution of martian atmospheric Ar, as well as the terrestrial atmosphere

Noble gases and K-Ar ages of five Rumuruti chondrites Yamato(Y)-75302, Y-791827, Y-793575, Y-82002, and Asuka-881988

Noble gases and K concentrations have been determined for aliquot samples prepared from the five Antarctic R-chondrites Yamato (Y)-75302,Y-791827,Y-793575,Y-82002,and Asuka (A)-881988. K-Ar ages of about 4.2Ga were obtained for Y-75302,Y-791827,Y-793575 and A-881988,while Y-82002 showed a slightly younger age of 3.9Ga. The Y-75302,Y-791827 and Y-82002 are enriched in solar light noble gases. Four meteorites Y-75302,Y-791827,Y-82002 and A-881988 have cosmic-ray exposure ages of about 20Ma, while the age of Y-793575 is about 7Ma. Based on the noble gas compositions and K-Ar ages, Y-75302 and Y-791827 are probably paired and Y-82002 may belong to this pair. Relatively high and variable ^Xe/^Xe ratios between 2-3.7 as well as enrichments of heavier Xe isotopes were observed in all R-chondrites

Noble gas signatures of Antarctic nakhlites, Yamato (Y) 000593, Y000749, and Y000802

We have measured noble gases in three nakhlites from Antarctica, Yamato (Y) 000593, Y000749, and Y000802, by step-heating and total-melting methods.The trapped ^Ar/^Kr/^Xe ratios determined for the bulk samples are around 80/3/1, identical to those of Nakhla. The Yamato nakhlites also release noble gases showing high ^Xe/^Xe (up to 1.486) and low ^Kr/^Xe (～1.5) at 1000 and 1300 ℃, which is one of the most characteristic signatures of nakhlites. The low ^Kr/^Xe, as compared to that of the Mars atmosphere, suggests the presence of a fractionated Martian atmosphere.Cosmic-ray exposure ages based on cosmogenic ^Ne are 11.7, 11.9, and 13.0 Ma for Y000593, Y000749, and Y000802, respectively. This supports the pairing based on the mineralogical and petrographical similarities and the location of the finds. The average of the ^Ne exposure ages is 12.05±0.69 Ma. We also calculated an apparent ^Kr-Kr age as 11.8±1.0 Ma from cosmic-ray produced radioactive ^Kr and stable Kr isotopes from Y000593. The coincidence with the ^Ne exposure age indicates a short terrestrial age (Ne exposure age and terrestrial age, is 12.1±0.7 Ma. Calculated K-Ar gas retention age for the Yamato nakhlites is 1.24±0.22 Ga. The ejection time and gas retention age are close to those of non-Antarctic nakhlites and Chassigny. This suggests that the Yamato nakhlites were ejected from Mars together with other nakhlites and Chassigny. Xenon isotopes are mixtures of Chassigny Xe, fission Xe, and the Mars atmosphere. High-temperature fractions (1000-1750℃) are enriched in the Mars atmosphere and fission Xe components, compared to lower temperature fractions. There are similarities in Xe isotopes between Y000749 and Y000802 showing excesses in ^Xe and ^Xe, whereas Y000593 has only small excesses. The release pattern of ^Xe for Y000593 is also dif

Cosmic-ray exposure ages of enstatite chondrites

Eleven enstatite (E-) chondrites were analyzed for abundances and isotopic ratios of noble gases by total melting. Light noble gases, He, Ne and Ar are discussed. We obtained cosmic-ray exposure ages (T^) based on cosmogenic ^Ne that are divided into two groups, below 15 Myr and above 40 Myr. Both ranges of T^ contain various petrologic-types of E-chondrites. Isotopic ratios and concentration of Ne for Yamato (Y)-8414 and -86004 are almost the same, which suggests that they are from a common fragment. Identical exposure age T^ of 10 Myr for Y-8414 and -86004 supports their pairing. The pairing for Y-8414 and -86004 based on noble-gas signatures and T^ is consistent with their petrologic similarities. Pairing for Y-792959 and -793161 is also suggested by their similarities in mineral compositions, their close sampling location and the same petrologic-type. However, there are discrepancies in He and Ar contents between the two samples, which fails to support their pairing. Including literature data, the exposure ages show no systematic correlation with petrologic type. Additionally, both EH-and EL-chondrites are found in both two peaks of T^. The exposure age distribution has no implications about the structure of E-chondrite parent body. The parent body of E-chondrites has possibly lost the original structure after many collisions in the early solar system evolution

A newly-developed guide can create tibial tunnel at an optimal position during medial meniscus posterior root repairs

Background During transtibial pullout repair of medial meniscus (MM) posterior root tears (MMPRTs), accurate tibial tunnel creation within the anatomic MM posterior root attachment seems critical. This study aimed to evaluate the tibial tunnel position created by a newly-developed Precision guide during pullout repair of MMPRTs. Methods In 40 patients who underwent transtibial pullout repairs, the tibial tunnel was created using the Unicorn Meniscal Root (UMR) (n = 20) or Precision guide (n = 20). Three-dimensional computed tomography images of the tibial surface were evaluated postoperatively, using Tsukada's measurement method. The expected anatomic center of the MM posterior root attachment was defined as the center of three tangential lines corresponding to anatomic bony landmarks. The expected anatomic center (AC) and the tibial tunnel center (TC) were evaluated using the percentage-based posterolateral location on the tibial surface. The difference in the mediolateral and anteroposterior percentage distance between the AC and TC was calculated, as was the absolute distance between the AC and TC. Results The mean AC was located 77.4% posterior and 40.1% lateral. The mean TC was similar in the UMR and Precision guide groups. There was no significant difference in the mediolateral percentage distance (UMR 3.9% vs. Precision 3.6%, p = 0.405), but a significant difference was observed in the anteroposterior percentage distance (UMR 3.5% vs. Precision 2.6%, p = 0.031). The mean absolute distance between the AC and TC was 3.9 mm and 3.5 mm (UMR and Precision guide groups, respectively) (p = 0.364). Conclusions The new Precision guide can create tibial tunnel in an optimal and stable position during pullout repair of MMPRTs

Development of Flat Tube Heat Exchanger for Heat Pump Air Conditoner

We developed a new type of a heat pump outdoor unit using an aluminum flat tube heat exchanger in order to improve the energy saving capability of an air conditioner. There are several difficulties in keeping a desired drainage performance, frost formation performance, as well as even distribution of refrigerant, when applying the flat tube heat exchanger to heat pump outdoor units. In order to achieve the same drainage performance and the frost formation performance as those of conventional heat exchangers, we have adopted new plate fins with ellipse cutouts. Flat tubes were inserted in the ellipse cutouts, and the slit position on a plate fin was properly adjusted. In order to achieve the even distribution of refrigerant, an aluminum distributor and 3-way pipes were installed to the evaporator. In this report, first we describe features of the flat tube heat exchanger. Next, we present and explain experimental results of the air-side heat transfer coefficient and the air-side pressure drop on the condition of dry, wet, and frost state respectively. Moreover, we present experimental results of the total heat transfer performance, including the refrigerant performance, under the conditions of the condensation and the evaporation. Finally, we explain the heat transfer performance and the effect of the flat tube heat exchanger to a conventional one in the case that the developed heat exchanger was mounted in heat pump outdoor unit

Preoperative Computed Tomography-Derived Bone Densities in Hounsfield Units at Implant Sites Acquired Primary Stability

The purpose of this study was to evaluate preoperative CT-derived bone densities in Hounsfield units (HU) at implant sites that acquired primary stability, and to compare these values to the optimal bone densities proposed in the literature. Fifty-one patients, 18 males (37 implant sites) and 33 females (67 implant sites) between 2003 and 2010 were assessed. CT data for different jaw sections, regions, and operating procedures were compared using the Kruskal-Wallis test and Scheffe's test for multiple comparisons (P < 0.05). The mean bone density in the maxilla was significantly lower than that in the mandible (P < 0.05); the mean bone densities in the 4 jaw regions decreased in the following order: anterior mandible > anterior maxilla > posterior mandible > posterior maxilla. The bone densities assessed by HU fell into the range of optimal bone densities associated with acquired primary implant stability proposed in the literature

Application of the cellular oxidation biosensor to Toxicity Identification Evaluations for high-throughput toxicity assessment of river water

Toxicity Identification Evaluation (TIE) is a useful method for the classification and identification of toxicants in a composite environment water sample. However, its extension to a larger sample size has been restrained owing to the limited throughput of toxicity bioassays. Here we reported the development of a high-throughput method of TIE Phase I. This newly developed method was assisted by the fluorescence-based cellular oxidation (CO) biosensor fabricated with roGFP2-expressing bacterial cells in 96-well microplate format. The assessment of four river water samples from Langat river basin by this new method demonstrated that the contaminant composition of the four samples can be classified into two distinct groups. The entire toxicity assay consisted of 2338 tests was completed within 12 h with a fluorescence microplate reader. Concurrently, the sample volume for each assay was reduced to 50 μL, which is 600 to 4700 times lesser to compare with conventional bioassays. These imply that the throughput of the CO biosensor-assisted TIE Phase I is now feasible for constructing a large-scale toxicity monitoring system, which would cover a whole watershed scale

Medial meniscus posterior root repairs: A comparison among three surgical techniques in short-term clinical outcomes and arthroscopic meniscal healing scores

Background Medial meniscus (MM) posterior root repairs lead to favorable clinical outcomes in patients with MM posterior root tears (MMPRTs). However, there are few comparative studies in evaluating the superiority among several pullout repair techniques such as modified Mason–Allen suture, simple stitch, and concomitant posteromedial pullout repair. We hypothesized that an additional pullout suture at the MM posteromedial part would have clinical advantages in transtibial pullout repairs of the MMPRTs. The aim of this study was to compare the clinical usefulness among several types of pullout repair techniques in patients with MMPRTs. Methods Eighty-three patients who underwent arthroscopic pullout repairs of the MMPRTs were investigated. Patients were divided into three groups using different pullout repair techniques: a modified Mason–Allen suture using FasT-Fix all-inside meniscal repair device (F-MMA, n = 28), two simple stitches (TSS, n = 30), and TSS concomitant with posteromedial pullout repair using all-inside meniscal repair device (TSS-PM, n = 25). Postoperative clinical outcomes and semi-quantitative arthroscopic meniscal healing scores (0–10 points) were evaluated at second-look arthroscopies. Results No significant differences among the three groups were observed in patient demographics and preoperative clinical scores, except for preoperative Lysholm scores. At second-look arthroscopies, there were no significant differences among the three techniques in postoperative clinical outcomes and meniscal healing scores. Conclusions This study demonstrated that the TSS-PM pullout repair technique did not show better scores in postoperative clinical outcomes and meniscal healings compared with the F-MMA and TSS techniques. Our results suggest that the concomitant posteromedial pullout suture may have no clinical advantage in the conventional pullout repairs for the patients with MMPRTs

Steep posterior slope of the medial tibial plateau is associated with ramp lesions of the medial meniscus and a concomitant anterior cruciate ligament injury

Background: Medial meniscus (MM) tears are associated with both acute and chronic anterior cruciate ligament (ACL) insufficiency and can lead to degenerative changes in the knee. ACL reconstruction (ACLR) combined with the meniscal repair was reported to result in decreased anterior knee joint laxity with evidence of improved patient-reported outcomes in the long term. However, a subtle tear of the MM posterior segment, also known as a ramp lesion, is difficult to detect on conventional magnetic resonance imaging (MRI) and is frequently missed in ACL-deficient knees. However, there are few studies about the associations between bone geometry and ramp lesion of the MM. This study aimed to compare sagittal medial tibial slope (MTS), medial tibial plateau depth (MTPD), and coronal tibial slope (CTS) between ACL-injured knees with and without ramp lesion of the MM. We hypothesised that patients with ramp lesion of the MM and a concomitant ACL injury have a steeper MTS and shallower MTPD than those without ramp lesion of the MM. Methods: Twenty-seven patients who underwent ACLR (group A), and 15 patients with combined MM repair (group AM) were included in the study. Anterior tibial translation (ATT) was measured under general anaesthesia just before surgery using a knee arthrometer. MRI was performed in the 10 degrees-knee-flexed position. The MTS and MTPD were measured on sagittal view, and the CTS was measured on coronal view. These parameters were compared between the groups. Differences in MRI measurements or patient demographics between the groups were evaluated using the Mann-Whitney U test. Results: No significant difference was observed in demographic data and post-operative side-to-side difference in ATT between both groups. Pre-operative ATT was significantly higher in group AM than in group A (P = 5.0 degrees than in those with MTS = 5.0 degrees, an occult MM ramp lesion should be strongly suspected, and surgeons should prepare for MM repair in combination with ACLR