794 research outputs found
Solvent drag measurement of transcellular and basolateral membrane NaCl reflection coefficient in kidney proximal tubule.
The NaCl reflection coefficient in proximal tubule has important implications for the mechanisms of near isosmotic volume reabsorption. A new fluorescence method was developed and applied to measure the transepithelial (sigma NaClTE) and basolateral membrane (sigma NaClcl) NaCl reflection coefficients in the isolated proximal straight tubule from rabbit kidney. For sigma NaClTE measurement, tubules were perfused with buffers containing 0 Cl, the Cl-sensitive fluorescent indicator 6-methoxy-N-[3-sulfopropyl] quinolinium and a Cl-insensitive indicator fluorescein sulfonate, and bathed in buffers of differing cryoscopic osmolalities containing NaCl. The transepithelial Cl gradient along the length of the tubule was measured in the steady state by a quantitative ratio imaging technique. A mathematical model based on the Kedem-Katchalsky equations was developed to calculate the axial profile of [Cl] from tubule geometry, lumen flow, water (Pf) and NaCl (PNaCl) permeabilities, and sigma NaClTE. A fit of experimental results to the model gave PNaCl = (2.25 +/- 0.2) x 10(-5) cm/s and sigma NaClTE = 0.98 +/- 0.03 at 23 degrees C. For measurement of sigma NaClbl, tubule cells were loaded with SPQ in the absence of Cl. NaCl solvent drag was measured from the time course of NaCl influx in response to rapid (less than 1 s) Cl addition to the bath solution. With bath-to-cell cryoscopic osmotic gradients of 0, -60, and +30 mosmol, initial Cl influx was 1.23, 1.10, and 1.25 mM/s; a fit to a mathematical model gave sigma NaClbl = 0.97 +/- 0.04. These results indicate absence of NaCl solvent drag in rabbit proximal tubule. The implications of these findings for water and NaCl movement in proximal tubule are evaluated
Comparison of Nitrate Contents for Reed Canarygrass and Orchardgrass in Large Amounts of Compound Fertilization
Reed canarygrass (Phalaris arundinacea L.) could be an ideal candidate for manure application. We compared its growth, crude protein (CP) and nitrate N (NO3-N) content to that of orchardgrass (Dactylis glomerata L.) on different levels of nitrogen fertilization (3,10,15 and 20g N m-2, applied from May 15 to September 15 after each monthly cutting. The dry weight (DW) of reed canarygrass increased significantly with increasing amounts of N nitrogen on July, August and September. However, orchardgrass only showed a significant increase in yield on September. The concentration of CP of reed canarygrass was significantly lower than that of orchardgrass with 3 g N m-2 on June, July, August and 10 g N m-2 on August. In contrast to this, CP of reed canarygrass was significantly higher than that of orchardgrass with 15 g N m-2 on July and 20 g N m-2 on July and August. NO3-N content of reed canarygrass was significantly lower than that of orchardgrass with 3 g N m-2 and 10 g N m-2 on June, July and August. We had high NO3-N (\u3e 0.15% N as NO3-N was considered unsafe) with 15 g N m-2 and 20 g N m-2 in both forage species and with 10 g N m-2 in orchardgrass. Our results indicate that reed canarygrass accumulates less NO3-N than orchardgrass with applications of 3 g N m-2 and 10 g N m-2 per cutting
Nonstructural Carbohydrate Reserves of Temperate Perennial Grasses in Autumn Early Growth
The objective of this study was to determine levels of nonstructural carbohydrate reserves of four temperate perennial grasses: Orchardgrass (Dactylis glomerata L.), Timothy (Phleum pratense L.), Perennial ryegrass (Lolium perenne L.), and Reed canarygrass (Phalaris arundinacea L.) in their early growth stages during the cool autumn temperatures in northern Japan. At the time of sampling, all grasses were in their vegetative stage, and Reed canarygrass was not forming rhizomes. Fructosan concentration in reed canarygrass roots (8.04%) was 22 times that of the leaf blade (0.36%) and twice that of the stem (3.40%); the concentration in reed canarygrass root was the highest of the four grasses. Timothy stored fructosan in the root at a significantly higher concentration (1.65%) than did the orchardgrass (0.58%) and perennial ryegrass (0.83%). The concentration of fructosan in the timothy was the highest in the stem, the lowest in the leaf blade and intermediate in the root. On the other hand, orchardgrass and perennial ryegrass stored the highest amount of fructosan in the stem, the lowest amount in the root, and an intermediate amount in the leaf blade. In addition, the root dry weight and the ratio of the root dry weight to the total dry weight were significantly higher in reed canarygrass than in the other three grasses. Timothy was in second place surpassing orchardgrass and perennial ryegrass. We considered that winter survival is the highest in reed canarygrass and second highest in timothy over orchard grass and perennial ryegrass
A determination of the LMC dark matter subhalo mass using the MW halo stars in its gravitational wake
Our goal is to study the gravitational effects caused by the passage of the
Large Magellanic Cloud (LMC) in its orbit on the stellar halo of the Milky Way
(MW). We employed the Gaia Data Release 3 to construct a halo tracers data set
consisting of K-Giant stars and RR-Lyrae variables. Additionally, we have
compared the data with a theoretical model to estimate the DM subhalo mass. We
have improved the characterisation of the local wake and the collective
response due to the LMC orbit. On the other hand, we have estimated for the
first time the dark subhalo mass of the Large Magellanic Cloud, of the order of
M, comparable to previously reported values in the
literature.Comment: submitted to A&
Nuclear response to dark matter signals in Ge and Xe odd-mass targets
Abstract: The interaction of dark matter particles (WIMPs) with the odd-mass
Ge and Xe target nuclei ,{ {that is the recoil rates
corresponding to the elastic scattering of WIMPs by these nuclei}}, is analysed
in the context of the minimal extensions of the SUSY model. The BCS+QRPA
technique plus the quasiparticle-phonon coupling scheme is used to describe the
nuclear structure part of the calculations. The resulting values for the
nuclear spin content of both nuclei are compared to values previously reported
in the literature
The performance of thin NaI(Tl) scintillator plate for dark matter search
A thin (0.05cm) and wide area (5cmX5cm) NaI(Tl) scintillator was developed.
The performance of the thin NaI(Tl) plate, energy resolution, single
photoelectron energy and position sensitivity were tested. An excellent energy
resolution of 20% (FWHM) at 60keV was obtained. The single photoelectron energy
was calculated to be approximately 0.42 0.02keV. Position information in the
5cmx5cm area of the detector was also obtained by analyzing the ratio of the
number of photons collected at opposite ends of the detector. The position
resolution was obtained to be 1cm (FWHM) in the 5cmx5cm area.Comment: 10 pages. Accepted to Journal of Physical Society of Japa
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