A1 Absorption Research Articles

Effect of supplementary irrigation on rice yield in dry land during rainy season

Climate change causes change in rainfall patterns, which will affect water availability. Water is a limiting factor for rice production on dry land. Increasing rice yields on dry land requires precise water management. This study aimed to investigate the effect of supplementary irrigation when it does not rain on rice yields in dry land during rainy season. The research was conducted on dry land in Playen, Gunung Kidul, Daerah Istimewa Yogyakarta, Indonesia during rainy season of November 2020 to February 2021. The treatments were supplementary irrigation if 1 day without rain (A1), if 2 days without rain (A2) and if 3 days without rain (A3), and they were compared to control without supplementary irrigation (A0). This research used a randomized completely block design, each treatments replicated 4 times. The results showed A1 gave the highest grain yield, namely 7.786 ton ha−1, significant different with other treatments of A2, A3 and A0. Dry straw of A1 was 7.324 ton ha−1, significant different with A2, A3 and A0. Carbon absorption of A1 was 6.860 ton ha−1, consisting of carbon in grain 3.575 ton ha−1 and straw 3.285 ton ha−1, it was significant different with other treatments of A2, A3 and A0 (p<0.05; n=16). B/C A2 1.73 was highest from the others and its farmers have profit Rp. 19,276,360 ha−1.

Pharmacokinetic studies of active triterpenoid saponins and the total secondary saponin from Anemone raddeana Regel.

The rhizome of Anemone raddeana Regel, a Traditional Chinese Medicine (TCM) which has a robust history treating rheumatism and neuralgia. The total secondary saponin (TSS) from it has demonstrated antitumor activity. In this study, a rapid and validated LC-MS/MS method was developed to simultaneously determine the active compounds (Hederacolchiside A1 and Eleutheroside K). Analytes were separated on a reverse-phase C18 column with acetonitrile-water (5mmol/L ammonium acetate) as the mobile phase. This assay showed acceptable linearity (r>0.99) over the concentration range 5-1000 nmol/L for two analytes. The intra- and inter-day precision was within 8.06% and accuracy was ranged from -3.16% to 3.34% for two analytes. The mean extraction recoveries of analytes and IS from rat plasma were all more than 76.0%. Under the developed analytical conditions, the obtained values of main pharmacokinetic parameters (Cmax and AUC0-t) indicated that the pure compounds were more efficient than the TSS extract in Hederacolchiside A1 and Eleutheroside K absorption. In addition, pharmacokinetic studies of two individual compounds demonstrated their poor oral absorption in rat (aF%, 0.019-1.521). In the study of absorption and transportation of Hederacolchiside A1 and Eleutheroside K in Caco-2 cell monolayer model, the uptake permeability was in 10-6cm/sec range suggesting poor absorption, which confirmed the previous pharmacokinetic profiles in vivo. Interestingly, the uptake ratio of them declined significantly when treated with phloridzin (SGLT1 inhibitor). It indicated that the absorption of Hederacolchiside A1 in intestine was mainly through positive transport and SGLT1 might participate in its active absorption.

Absorption and Transport of Sea Cucumber Saponins from Apostichopus japonicus.

The present study is focused on the intestinal absorption of sea cucumber saponins. We determined the pharmacokinetic characteristics and bioavailability of Echinoside A and Holotoxin A1; the findings indicated that the bioavailability of Holotoxin A1 was lower than Echinoside A. We inferred that the differences in chemical structure between compounds was a factor that explained their different characteristics of transport across the intestine. In order to confirm the absorption characteristics of Echinoside A and Holotoxin A1, we examined their transport across Caco-2 cell monolayer and effective permeability by single-pass intestinal perfusion. The results of Caco-2 cell model indicate that Echinoside A is transported by passive diffusion, and not influenced by the exocytosis of P-glycoprotein (P-gp, expressed in the apical side of Caco-2 monolayers as the classic inhibitor). The intestinal perfusion also demonstrated well the absorption of Echinoside A and poor absorption of Holotoxin A1, which matched up with the result of the Caco-2 cell model. The results demonstrated our conjecture and provides fundamental information on the relationship between the chemical structure of these sea cucumber saponins and their absorption characteristics, and we believe that our findings build a foundation for the further metabolism study of sea cucumber saponins and contribute to the further clinical research of saponins.

Electronic Characterization of Reaction Intermediates: The Fluorenylium, Phenalenylium, and Benz[f]indenylium Cations and Their Radicals.

Three vibrationally resolved absorption systems commencing at 538, 518, and 392 nm were detected in a 6 K neon matrix after mass-selected deposition of C13 H9 (+) ions (m/z=165) produced from fluorene in a hot-cathode discharge ion source. The benz[f]indenylium (BfI(+) : 538 nm), fluorenylium (FL9(+) : 518 nm), and phenalenylium (PHL(+) : 392 nm) cations are the absorbing molecules. Two electronic systems corresponding to neutral species are apparent at 490 and 546 nm after irradiation of the matrix with λ<260 nm photons and were assigned to the FL9 and BfI radicals, respectively. The strongest peak at 518 nm is the origin of the 2 (1) B2 ←X̃ (1) A1 absorption of FL9(+) , and the 490 nm band is the 2 (2) A2 ←X̃ (2) B1 origin of FL9. The electronic systems commencing at 538 nm and 546 nm were assigned to the 1 (1) A1 ←X̃ (1) A1 and 1 (2) A2 ←X̃ (2) A2 transitions of BfI(+) and BfI. The 392 nm band is the 1 (1) E'←X̃ (1) A1 ' transition of PHL(+). The electronic spectra of C13 H9 (+) /C13 H9 were assigned on the basis of the vertical excitation energies calculated with SAC-CI and MS-CASPT2 methods.

A RARE ENCOUNTER WITH VERY MASSIVE STARS IN NGC 3125-A1

Super star cluster A1 in the nearby starburst galaxy NGC 3125 is characterized by broad He\ii \lam1640 emission (full width at half maximum, $FWHM\sim1200$ km s$^{-1}$) of unprecedented strength (equivalent width, $EW=7.1\pm0.4$ \AA). Previous attempts to characterize the massive star content in NGC 3125-A1 were hampered by the low resolution of the UV spectrum and the lack of co-spatial panchromatic data. We obtained far-UV to near-IR spectroscopy of the two principal emitting regions in the galaxy with the Space Telescope Imaging Spectrograph (STIS) and the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (\hst). We use these data to study three clusters in the galaxy, A1, B1, and B2. We derive cluster ages of 3-4 Myr, intrinsic reddenings of $E(B-V)=0.13$, 0.15, and 0.13, and cluster masses of $1.7\times10^5$, $1.4\times10^5$, and $1.1\times10^5$ M$_\odot$, respectively. A1 and B2 show O\vb \lam1371 absorption from massive stars, which is rarely seen in star-forming galaxies, and have Wolf-Rayet (WR) to O star ratios of $N(WN5-6)/N(O)=0.23$ and 0.10, respectively. The high $N(WN5-6)/N(O)$ ratio of A1 cannot be reproduced by models that use a normal IMF and generic WR star line luminosities. We rule out that the extraordinary He\ii \lam1640 emission and O\vb \lam1371 absorption of A1 are due to an extremely flat upper IMF exponent, and suggest that they originate in the winds of very massive ($>120\,M_\odot$) stars. In order to reproduce the properties of peculiar clusters such as A1, the present grid of stellar evolution tracks implemented in Starburst99 needs to be extended to masses $>120\,M_\odot$.

Miscibility, crystallization and annealing studies of poly(vinylidene fluoride)/hyperbranched polyester blends

In this study, miscibility and crystallization behavior of polyvinylidene fluoride (PVDF) and its blends with hyperbranched polyester (HBPE, 0 to 50 wt.-% of HBPE in PVDF) are investigated by means of DSC and FTIR techniques. Among the varying blend compositions, PVDF/HBPE (100/0 and 90/10) blend ultrathin film samples were subjected to thermal annealing at different temperatures (30–200 °C) in order to examine and compare their crystallization behavior. From FTIR data, the all-trans band (A1) at ca. 1280 cm−1 corresponding to the changes in ferroelectric β-crystalline phase for both the samples exhibits higher absorption intensity upon annealing at 90 °C, well below their melting temperature range (Tm∼160 °C), whereas, the sample melt-annealed at 210 °C exhibit reduced A1 absorption intensity, which is attributed to the crystalline transformation from ordered ferroelectric phase into the disordered amorphous phase. Quantitative data from Factor analysis revealed the existence of higher ferroelectric β-crystalline phase content in PVDF/HBPE (90/10) blend ultrathin film sample than in commercially available PVDF and PVDF/TrFE (72/28) ultrathin film samples, which exemplifies the importance of this study. The enhanced ferroelectric characteristics exhibited by the PVDF/HBPE (90/10) blend ultrathin film samples can be well-suited for electronic applications such as non-volatile memory devices, sensors, etc.

ATP-binding cassette transporter A1, fatty acids, and cholesterol absorption.

A significant advance in our understanding of the reverse cholesterol transport pathway occurred in 1999 with the identification of defects in the ATP-binding cassette transporter A1 gene as the cause of Tangier disease. Since this discovery, an overwhelming number of experiments have been conducted to further define the function of this gene. Among the concepts emerging from such studies is a possible role for the gene in cholesterol absorption. The present review summarizes the most recent of these studies, as well as the only report to describe the effects of fatty acids on ATP-binding cassette transporter A1 gene activity. From the one study conducted thus far, it appears that unsaturated fatty acids can reduce ATP-binding cassette transporter A1 gene activity by enhancing its degradation. Among the primary modulators of the gene's transcription is the liver X receptor, with liver X receptor-selective agonists significantly increasing expression of the gene. While some studies indicate that upregulation of the gene inhibits cholesterol absorption, the results of other studies suggest that it facilitates cholesterol absorption and the transfer of cholesterol into the bile. Preliminary evidence from studies with transgenic and knockout mice supports the concept that increasing ATP-binding cassette transporter A1 gene expression may be beneficial in the prevention of diet-induced atherosclerosis. Although there is substantial evidence from and studies to suggest that the ATP-binding cassette transporter A1 gene regulates intestinal cholesterol absorption, perhaps by mediating cholesterol efflux from the basolateral surface of enterocytes, it remains unclear whether or not this gene is the primary ATP-binding cassette transporter involved in the process.

Influence of crystal properties on the absorption IR spectra of polycrystalline AlN thin films

In this paper Fourier transform infrared (FTIR) transmission spectroscopy is presented as a technique suitable for the routine morphological study of polycrystalline AlN thin films. We have compared FTIR spectra and X-ray diffraction (XRD) patterns of wurtzite polycrystalline AlN films deposited on Si(001) by RF reactive sputtering of an Al target in an N 2/Ar mixture. The preferred orientation and crystal quality of the films were investigated by XRD. The FTIR spectra showed absorption bands due to vibrational modes of AlN bonds, in particular, the A1(TO) mode at 612 cm −1 and the E1(TO) mode at 672 cm −1. The ratio of integrated areas of A1(TO) and E1(TO) absorption bands is related to the preferred orientation of the films, which ranges from films with purely (00.2)-oriented grains to films with grains tilted by approximately 60° to the surface normal. Energy shifts of the IR absorption modes were observed in relation to biaxial residual stress present in the films. As residual stress varied from tensile to compressive, E1(TO) peak energy increased, while A1(TO) peak energy decreased. It is concluded that FTIR transmission spectroscopy has the potential to be used as a routine characterization technique for in-line process control of polycrystalline AlN thin films.

Crystal structure of ABPO5 and optical study of Pr3+ embedded in these compounds

The crystal structure of borophosphates ABPO5 (A = alkaline earth or Pb) was resolved on a polycrystalline sample using the Rietveld method. The x-ray diffraction patterns data show that ABPO5 crystallize in a centrosymmetric space group P3121 and their structure is related to the borogermanates REBGeO5 with a stillwellite-type structure. Pr3+ ion was used as a local structural probe to corroborate the structural resolution results. Absorption and fluorescence spectra of A1−xPrxBP1−xGexO5 (A = alkaline earth or Pb; x = 0.05) have been investigated at different temperatures. At 9 K the 3H4 → 3P0 transition of trivalent praseodymium ion (4f2 configuration) is observed as a single line. This indicates a unique crystallographic site for the rare earth ion in these compounds replacing the divalent cation. Energy level schemes were deduced from the low-temperature spectroscopic measurements. Comparing the electronic level splittings of studied compounds with the already reported data on REBGeO5 doped with Pr3+ ion, it is possible to dispel the doubt existing about structural determination. Moreover, under 460 nm excitation, intense red emission of trivalent praseodymium is observed corresponding to 1D2 → 3H4 transition. The lifetime measurements of 1D2 level have been performed for all the title compounds.

Validity of IRI electron density profiles in relation to vertical incidence absorption measurements

The observed discrepancies between A1 absorption meaurements and numerical estimation of the same using IRI electron density profiles are attributed to the assumption made in the Sen-Wyleer generalized magneto-ionic theory that the momentum transfer collision frequency of electrons with neutrals is proportional to the square of the electron thermal speed. Based on Budden's (1985) suggestion that, in the lower thermosphere and mesosphere, the momentum transfer collision frequency is proportional to the electron thermal speed, a generalized magneto-ionic theory has been outlined. The new theory brings experimental measurements of A1 absorption closer to the theoretical deductions based on IRI-90 electron density profiles.

Comparison of IRI profile with low latitude A1 absorption measurements — A summary

Comparison of the IRI-90 profiles for the lower ionosphere with those derived from A1 absorption measurements indicate that the IRI-90 values of electron density are consistently higher in the lower E-region. It is suggested that LAY function representation of electron density in the lower ionosphere be provided as an option in the IRI description.

Room-temperature radiation effects in Al-doped Y-bar quartz

Infrared and optical spectra were measured for synthetic quartz in Y-bar form, as it received progressive dosage of gamma -irradiation. The gamma -induced coloration varied in intensity over different growth regions of the Y-bar, in proportion to the density of aluminium impurities, the latter being dependent on the growth speed of the region in question as well as the polarization effect of the x-axis. From the variations in absorbance within the conventionally designated S4, e2 and A1 absorption bands, we deduce that, over a broad range of dosage, Al-OH defects increased continuously while as-grown OH sites hardly decreased in concentration. This indicates the presence of another kind of as-grown A centre that does not show up in IR absorption. It is most noticeable in the -x region, which, like air-swept quartz, has a low radiation susceptibility.

Upconversion by excited state absorption of Pb+(1) centres in alkaline-earth fluorides

Pb+(1) centres in alkaline-earth fluorides consisting of a substitutional Pb+ ion next to a F- vacancy have shown IR emissions (SrF2 at 1.17 eV) when excited in their A1 absorption bands (SrF2 at 1.87 eV). In contrast to the analogous Pb+(1) centres in KMgF3 they could not be brought to lase. It is shown that this failure occurs because of a loss mechanism in which excited-state absorption leads to an 'upconversion' emission peaking at 2.375 eV for CaF2, 2.361 eV for SrF2 and 2.370 eV for BaF2. Its intensity depends quadratically on the pump power and it can also be excited in the A3 band in the UV. A theoretical calculation shows that the upconversion emission originates from the relaxed excited state of a FA-centre model rather than from a 6s27s excited Pb+(1) state and explains its observed temperature dependence. The upconversion is observed in the alkaline-earth fluorides because of an accidental energy resonance 2A1=A3 that does not occur in KMgF3.

Effect of Lactate on the Absorption and Retention of Aluminum in the Remnant Kidney Rat Model

In previous investigations we found the gastrointestinal absorption of aluminum (Al) to be enhanced in uremic rats and this phenomenon could not be attributed to either calcitriol deficiency or secondary hyperparathyroidism. The purpose of this study was to examine whether carboxyl ligands such as lactate could affect the absorption of A1 in our model and, if so, whether this would impose additional alterations on the A1 absorption in uremia. Uremic rats and controls were studied with single oral loads of either A1 chloride or A1 lactate and, subsequently, urinary A1 excretion was measured for 5 days. Compared with Al chloride, administration of A1 lactate resulted in significantly higher urinary excretion rates of A1 in uremic rats (55.5 +/- 22.7 vs. 27.4 +/- 7.0 micrograms; 2.06 +/- 0.84 vs. 1.01 +/- 0.26 mumol) and in controls (23.6 +/- 8.5 vs. 11.9 +/- 4.3 micrograms; 0.87 +/- 0.31 vs. 0.44 +/- 0.16 mumol). However, with either A1 load the recovery of A1 from urine was substantially higher in uremic animals. In contrast, only in controls was there a more pronounced rise in serum A1 concentrations following ingestion of A1 lactate, whereas in uremic rats this increase had a similar magnitude following A1 chloride and A1 lactate, suggesting a larger apparent volume of distribution of the latter. Adjustment of the pH of the A1 lactate-containing solution to 7.0 or oral administration of sodium lactate together with A1 chloride yielded essentially similar results. These observations indicate that the enhanced intestinal absorption of A1 in uremia is further augmented by lactate regardless of the mixture of hydroxolactato complexes employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of transforming growth factor alpha in normal, malignant, and hyperproliferative human keratinocytes.

Transforming growth factor alpha (TGF-alpha) is a 50-amino acid peptide, previously demonstrated only in transformed cell lines and human tumors, which is structurally homologous to epidermal growth factor (EGF). TGF-alpha expression in keratinocytes from normal individuals, patients with psoriasis, and patients with malignant skin diseases was investigated using an mAb raised against synthetic human TGF-alpha. mAb A1.5 reacted with TGF-alpha, but not EGF, in a sensitive ELISA. Keratinocytes in eight nodular basal cell carcinomas, one morpheic basal cell carcinoma, and one squamous cell carcinoma demonstrated intense membranous immunoperoxidase staining with mAb A1.5. Of even greater interest was the observation that the overlying normal epidermis, as well as the epidermis from five normal skin specimens, were stained by the mAb. Keratinocytes in plaques from 18 psoriasis patients were more intensely stained than those from normal skin. Cultured normal keratinocytes demonstrated membranous staining with mAb A1.5. Absorption of mAb A1.5 with synthetic human TGF-alpha completely removed the reactivity of mAb A1.5 with both basal cell tumors and normal epidermis. The demonstration of TGF-alpha in normal keratinocytes suggests that it plays a role in normal keratinocyte growth, wound healing, and in the pathogenesis of acanthosis.

Input from station-oriented observations and its assimilation into the new formula for the International Reference Lower Ionosphere (IRLI)

In order to compare the station-oriented observations from a variety of experimental techniques, it is necessary to use standard and state-of-the art procedures for the methods of evaluation. While discussing the formulae used in the past for the calculation of mf/hf radio wave absorption and vlf/lf reflection coefficients, the use of the Sen-Wyller formula for the computation of A1 absorption at mf/hf and the use of generalised full wave theory for the calculation of vlf/lf reflection coefficients are recommended. For oblique incidence mf/hf (A3) absorption calculations, use of the generalised Booker quartic is recommended. The need to use a consistent and standard collision frequency model linked with the CIRA pressure model is recommended. While discussing the normalisation procedures used in the past for the global mapping of the D- and lower-E-region A1 absorption, the need to calculate the absorption (without normalisation) and then make a comparison with the IRI description is stressed. The use of the currently available rocket data, to model the peak parameters of the E-region, is discussed. More rocket observations to probe the E-region together with incoherent scatter data are needed to model the E-region peak parameters needed for incorporation into the new formula for the International Reference Lower Ionosphere (IRLI).

A test of the International Reference Ionosphere using single-frequency A1 data

A1 absorption and virtual reflection height data recorded at Camden, Australia during the period February 1980–January 1981 were compared with values calculated using the latest version of the International Reference Ionosphere—IRI 79. Systematic differences of 10–25 dB in absorption and 2–4 km in virtual height indicate that the IRI electron densities are too high for the lower ionosphere. A better fit between theory and experiment at Camden may be achieved by extending the top altitude of the D-region (i.e. the IRI parameter HDX) and by using a different profile shape to connect the D-region to the peak of the E-region.

On the use of virtual reflection height information to interpret single-frequency A1 absorption measurements

If the A1 data collected at Camden, Australia, is sorted into 2 km virtual height bins, then the echo amplitudes are observed to increase as the overall virtual height decreases. Model calculations show that this behaviour can be simulated by introducing a sharp increase in electron-density gradient near the reflection level. This appears to truncate the extent of the ray path in the deviative region and leads to a fall in absorption. Since the deviative component of the absorption is a large fraction of the total absorption (at the observing frequency of 1.91 MHz), this reduction can be dramatic. This mechanism is believed to be the main source of variability in single-frequency A1 absorption measurements.

Ledge effect in A1 absorption measurements

The short-term variability in A1 absorption measurements for Camden (34°S, 151°E) is caused by changes in the deviative component of absorption. These changes, in turn, are caused by enhanced electrondensity gradients (referred to here as ‘ledges’) near the reflection level. The ledges perturb the normal E-region electron density profile and introduce a bias (termed the ‘ledge effect’) into the absorption measurements. In the present experiment, the ledge effect was isolated by using the virtual reflection height information to interpret the A1 absorption measurements. During the period of this study (February 1980–January 1981), the ledge effect was observed to have both diurnal and seasonal variations. The effect was most noticeable in the afternoon around the equinoxes, but was essentially absent during the summer months.

Experimental investigations of ionospheric/stratospheric coupling in southern mid latitudes—1. Spectra and cross-spectra of stratospheric temperatures and the ionospheric ƒ-min parameter

Spectra of the variance and coherence of stratospheric (100, 50 and 30 mb) temperature and of ionosonde ƒ-min during 1964–1967, show an increase in the variance and coherence (between layers) of temperatures from 100 to 30 mb in the stratosphere over Christchurch (44°S 172°E) and Campbell Island (53°S 169°E) at periods greater than seven days, and particularly in winter. The seasonal variation of ƒ-min variance is shown to be a function of magnetic activity (ΣK). The coherence of the Christchurch temperatures and Campbell Island ƒ-min is significant at frequencies of about 0.15 days − (periods of ~6 days) in both winter and summer. Comparison of the Godley Head (Christchurch) ƒ-min with (nearby) Birdlings Flat A1 absorption measurements indicated that the former is not as good a measure of ionospheric absorption as the Campbell Island ƒ-min