ASC Systems Research Articles

Instance-level loss based multiple-instance learning framework for acoustic scene classification

An acoustic scene is inferred by detecting properties combining diverse sounds and acoustic environments. This study is intended to discover these properties effectively using multiple-instance learning (MIL). MIL, also known as a weakly supervised learning approach, is a strategy for extracting an instance vector from an audio chunk that composes an audio clip and utilizing these unlabeled instances to infer a scene corresponding to the input data. However, many studies pointed out an underestimation problem of MIL. In this study, we propose an enhanced MIL framework more suitable for ASC systems by defining instance-level labels and loss to extract and cluster instances effectively. Furthermore, we design a lightweight convolutional neural network named FUSE comprising frequency-, temporal-sided depthwise, and pointwise convolutional filters. Experimental results show that the confidence and proportion of positive instances significantly increase compared to vanilla MIL, overcoming the underestimation problem and improving the classification accuracy even higher than the supervised learning. The proposed system achieved a performance of 81.1%, 72.3%, and 58.3% on the TAU urban acoustic scenes 2019, 2020 mobile, and 2022 mobile datasets with 139 K parameters, respectively. In particular, it achieves the highest performance among the systems having under the 1 M parameters for the TAU urban acoustic scenes 2019 dataset.

Comprehensive genomic and phenotypic metal resistance profile of Pseudomonas putida strain S13.1.2 isolated from a vineyard soil.

Trace metals are required in many cellular processes in bacteria but also induce toxic effects to cells when present in excess. As such, various forms of adaptive responses towards extracellular trace metal ions are essential for the survival and fitness of bacteria in their environment. A soil Pseudomonas putida, strain S13.1.2 has been isolated from French vineyard soil samples, and shown to confer resistance to copper ions. Further investigation revealed a high capacity to tolerate elevated concentrations of various heavy metals including nickel, cobalt, cadmium, zinc and arsenic. The complete genome analysis was conducted using single-molecule real-time (SMRT) sequencing and the genome consisted in a single chromosome at the size of 6.6 Mb. Presence of operons and gene clusters such as cop, cus, czc, nik, and asc systems were detected and accounted for the observed resistance phenotypes. The unique features in terms of specificity and arrangements of some genetic determinants were also highlighted in the study. Our findings has provided insights into the adaptation of this strain to accumulation and persistence of copper and other heavy metals in vineyard soil environment.Electronic supplementary materialThe online version of this article (doi:10.1186/s13568-016-0269-x) contains supplementary material, which is available to authorized users.

Experimental and modeling study of a dual-layer (SCR + PGM) NH3 slip monolith catalyst (ASC) for automotive SCR aftertreatment systems. Part 1. Kinetics for the PGM component and analysis of SCR/PGM interactions

We present herein the first of two parts in the development and validation of a chemically and physically consistent mathematical model of a commercial dual-layer (SCR+PGM) monolithic NH3 slip converter (ASC). The overall project followed a systematic approach of growing complexity, and its results emphasize the beneficial features of a dual-layer configuration with the SCR catalyst on top of the PGM component. Specifically, we report in this paper NH3/O2/NONO2 steady-state and transient kinetic runs performed over the PGM component of the dual-layer NH3 slip catalyst. The PGM component was tested in a representative temperature range (150–550°C) in the form of precursor washcoat powders at high space velocities in order to gain kinetic information. From these data an original global PGM kinetic model was developed, which fully accounts for the effects of temperature and of NO2/NOx feed ratio (0–1) on NH3 oxidation. The model considers NO2 inhibition on NO oxidation, as well as a novel NO2 inhibition effect on the NH3 oxidation reactions. Comparative NH3/O2/NONO2 steady-state runs were performed also over two combinations of SCR+PGM powders (sequential double-bed and mechanical mixture). The N2 selectivity was greater over the mechanical mixture, as in this configuration the unselective NH3 oxidation products (NOx) formed over the PGM catalyst had a chance to further react selectively with NH3 over the SCR catalyst. Such a positive interaction between the PGM and the SCR catalytic chemistries was satisfactorily predicted by a model involving the simple superposition of the PGM and SCR kinetics. In the following part of the project the herein developed PGM kinetics, together with consistent SCR kinetics, will be incorporated in a novel dual-layer monolith catalyst model and validated against both lab-scale and engine test bench data collected over dual-layer ASC systems.

L-leucine and L-alanine uptake by trout ( Salmo trutta ) cardiomyocytes: the effect of IGF-I and insulin

The uptake of L-leucine and L-alanine by trout cardiomyocytes was analysed to identify the carriers involved in their incorporation into cells. The sodium independent systems L and asc, as well as the sodium dependent system ASC, were found to be present. The Vmax of these carriers was 33.0, 40.1 and 19.4 pmol amino acid mg−1 prot min−1 for L, asc and ASC, respectively, and the Km values obtained for these transport systems were 296, 269 and 349 μM amino acid. The L system had as its main substrates the large apolar branched-chain amino acids and showed stereospecificity. The asc and ASC systems carried the short-chain neutral amino acids and were not inhibited by Me-AIB. The ASC transporter also showed adaptive regulation. The effect of IGF-I and insulin on L-alanine uptake, as well as the incorporation of L-leucine into protein, were also studied. Low IGF-I concentrations (below 2.5 ng ml−1) stimulated the uptake of L-alanine and protein synthesis but this effect reverted at high IGF-I concentrations. Insulin depressed protein synthesis and did not affect L-alanine uptake.

Characterization of cystine uptake in cultured astrocytes

Glutathione is involved in the maintenance of the structural and functional integrity of membrane proteins, in protection against free radicals and oxidative stress, and in the detoxification of xenobiotics. The cellular uptake of cystine is the rate limiting step in the biosynthesis of glutathione. The precise mechanism for such uptake is not clear as some reports indicate that the uptake occurs through a glutamate–cystine antiporter (system X c – ), whereas, others suggest that it is taken up by the glutamate transporter (system X AG ). Our studies in cultured astrocytes derived from neonatal rats showed that glutamate, D- and L-aspartate inhibited cystine uptake; that factors that increased intracellular glutamate levels, which would have enhanced the activity of the antiporter, did not stimulate cystine uptake; that the uptake was sodium dependent and partially chloride dependent; that the b o,+ and ASC systems, which have been shown to carry cystine in some cells, did not mediate cystine uptake in astrocytes; that glutamate uptake blockers such as L-aspartate-β-hydroxamate (AβH) and L- trans-pyrrolidine-2,4-dicarboxylate (PDC), as well as cystine uptake inhibitor L-α-aminoadipate (AAA) potently reduced cystine uptake. Additionally, deferoxamine (100 μM) as well as ammonium chloride (5 mM), both of which inhibit glutamate uptake, also inhibited cystine uptake. Taken together, our findings indicate that astrocytes take up cystine through a similar, if not identical, system used to take up glutamate. Interference of cystine uptake by astrocytes through the glutamate transport system may have profound effects on the redox state and the structural and functional integrity of the CNS.

Seasonal variation in uptake of short-chain neutral amino acid by red blood cells and hepatocytes in trout (Salmo trutta).

The present study shows that the capacity of trout (Salmo trutta) red blood cells (RBCs) and freshly isolated hepatocytes to take up short-chain neutral amino acids changes according to a seasonal pattern. Maximal amino acid uptake rates in RBCs were obtained in winter and spring, while minima were seen in summer and autumn. In contrast, the maximal rates for the freshly isolated hepatocytes were obtained in autumn and winter, and the minima were seen in spring and summer. In addition, by studying the uptake of glycine, evidence was found that the activities of the amino acids carriers ASC, asc and Gly in RBCs varied according to a seasonal rhythm. The activity of the ASC and asc systems changed in parallel with the global uptake of amino acids. Moreover, the RBC:plasma concentration ratio for certain substrates of these carriers (alanine, serine and glycine) varied accordingly. In contrast, the activity of the Gly system was modified inversely with respect to the overall amino acid uptake. The activity of the ASC system in freshly isolated hepatocytes was also seasonally modified, reaching a maximum in autumn, shortly before the reproductive period.

Influence of hypo-osmolality on the activity of short-chain neutral amino acid carriers in trout (Salmo trutta) red blood cells.

The present study shows that in trout red blood cells the activity of some amino acid carriers, not directly involved in cell volume regulation, is affected by external osmolality. Glycine uptake has been used as the experimental approach because it was shown previously that it is effected by different carriers, namely the Na+-dependent ASC and Gly systems, as well as the Na+-independent asc and L systems. An increase in the uptake through the Gly system and the two Na+-independent carriers was found, while the ASC system appeared to be downregulated. Those systems whose activities were increased by hypo-osmolality did not share the mechanism by which this increase was obtained. Thus, the Gly system was sensitive to intracellular ionic changes, while the Na+- independent systems were mechanically stimulated, as assessed by the iso-osmotic swelling caused by ammonium chloride. On the other hand, a volume-sensitive transporter may be present in trout red blood cells, which is involved in the swelling-induced glycine movement, as can be deduced from the effect of some inhibitors such as pyridoxal phosphate, DIDS (4,4'-diisothiocyanate-stilbene-2,2'-disulfonic acid) and quinine.

Na(+)-independent L-alanine uptake by trout cells. Evidence for the existence of at least two functionally different acs systems.

The Na(+)-independent uptake of L-alanine has been studied in trout red blood cells, isolated hepatocytes and peripheral blood lymphocytes. The present study shows the existence of two functionally different Na(+)-independent systems for short chain neutral amino acids in these cells. They are designated as asc systems because of their resemblance to systems described in other cell types. Besides their independence of sodium and a rough similarity in substrate preference, the most important property shared by the two carriers is a lack of trans-stimulation, allowing further differentiation from system L. One of them is an unusually stereospecific carrier present in red blood cells, the other is less restrictive and present in hepatocytes and peripheral blood lymphocytes. Extracellular acid pH increases the incorporation to red blood cells, while it slightly depresses the uptake in the other cells. From the data presented, it is not possible, at first, to classify these carriers as asc1 or asc2 systems. Moreover, the system present in red cells resembles that found in the nonerythroid cells, BSC-1, while there is no clear parallelism between the system found in hepatocytes/lymphocytes and any of those described previously.

Changes in alanine and glutamine transport during rat red blood cell maturation.

Alanine and glutamine transport have been studied during red blood cell maturation in the rat. Kinetic parameters of Na(+)-dependent L-alanine transport were: Km 0.43 and 1.88 mM and Vmax 158 and 45 nmoles/ml ICW/min for reticulocytes and erythrocytes, respectively. During red cell maturation in the rat there is a loss of capacity and affinity of the system ASC for L-alanine transport. The values for Na(+)-dependent L-glutamine transport in reticulocytes were Km 0.51 mM and Vmax 157 nmoles/ml ICW/min. On the other hand, a total loss of L-glutamine transport mediated by both N and ASC systems is demonstrated in mature red cells. This seems to indicate that during rat red cell maturation the system N disappears. Furthermore, the system ASC specificity in mature cells changes, and glutamine enters the red cell by non-mediated diffusion processes.

Transport of L-tyrosine by B16/F10 melanoma cells: the effect of the intracellular content of other amino acids

The uptake of L-Tyr by B16/F10 malignant melanocytes in culture has been studied. These melanoma cells can either be depleted of amino acids by 1 h preincubation in Hanks' isotonic medium or preloaded with a specific amino acid by 1 h preincubation in the same solution containing 2 mM of the amino acid to be preloaded. By means of these pretreatments, it is shown that the rate of L-Tyr uptake is greatly dependent on the content of other amino acids inside the cells. The L-Tyr uptake is higher in cells preloaded with amino acids transported by the L and ASC systems than in cells depleted of amino acids or preloaded with amino acids transported by the A system. It is concluded that L-Tyr is mainly taken up by an exchange mechanism with other amino acids mediated by the L1 system, although the ASC system can also participate in the process. In agreement with that, the homo-exchange performed by cells preloaded with unlabelled L-Tyr is more efficient than any other hetero-exchange, although L-Dopa, the product of tyrosine hydroxylation in melanin synthesis, is almost as efficient as L-Tyr. Apart from aromatic amino acids, melanoma cells preloaded with L-Met and L-His also yield a high initial rate of L-Tyr uptake. The results herein suggest that melanoma cells do not have transport systems specific for L-Tyr, even if this amino acid is needed to carry out the differential pathway of this type of cells, melanosynthesis.

A Study of the Membrane Transport of Aminoacids in Erythrocytes from Patients on Haemodialysis

The initial rates of aminoacid influx to erythro cytes from nine patients on maintenence haemodialysis and from nine normal controls have been studied using radiolabelled L-serine, glycine, L-tryptophan and L-leucine. L-serine uptake had an Na-dependent component fitted by Michaelis-Menten kinetics (ASC system) and a non-saturable Na-independent component. In erythrocytes from haemodialysis patients L-serine uptake via the ASC system had a mean (SEM) Vmax of 233 (33) micromol/1 cells per h, compared to a mean Vmax in controls of 353 (21) micromol/l cells per h. The mean Km for L-serine uptake was 105 (11) microM in haemodialysis erythrocytes and 160 (12) microM in controls. These reductions in Vmax and Km for ASC in haemodialysis erythrocytes were significant (2P < 0.02). Glycine uptake had a Michaelis-Menten-type chloride-dependent component (gly system), and a chloride-independent non-saturable component. The mean Km for glycine influx via the gly system was 26.3 (2.3) microM in haemodialysis erythrocytes, and 34 (3.1) microM in normals (2P < 0.02). The Vmax for the uptake of glycine by the gly system did not differ significantly between haemodialysis and control erythrocytes. The initial influx rates of L-tryptophan via the T system and of L-leucine via the L system did not vary between control and haemodialysis erythrocytes. It is suggested that abnormalities of the ASC and gly membrane transport systems may contribute to the altered interorgan transport of aminoacids found in renal disease.

Processus de transport à travers la barrière hémato-encéphalique

The existence of the blood-brain barrier is due to tight junctions between endothelial cells preventing the passage of liquid and solute material at the capillary level. Substances can thus pass across the blood-brain barrier if they are lipophilic or if they have transport systems in the membranes of endothelial cells. The luminal membrane brings metabolites needed for the brain function, the abluminal one plays an important part in removing substances from brain, this can happen against a concentration gradient and thus needs energy. Ions are transported differently by the 2 membranes. Sodium and chloride have carriers and potassium is transported very actively by the sodium-potassium ATPase of the abluminal membrane. Blood-brain glucose influx is very important and happens by carrier transport at the 2 membranes. Efflux seems to use the same transport system as the influx. Transport of ketone bodies seems to happen only from blood to brain, the carriers being reversibly used for brain-blood transport of pyruvic and lactic acid. Amino-acid transport is very different on the luminal and abluminal membranes. On the luminal membrane there are 2 transport systems, one for basic amino acids, the other one, the L system, for neutral amino-acids. All neutral amino-acids are transported through the abluminal membrane by the L, A and ASC systems. There exists a system of transport for basic amino-acids, and a very active one for acid amino-acids. Some systems for the transport of hormones, vitamins and for some peptides exist also at the blood-brain barrier which thus plays a very important role in the regulation of brain metabolism.

Dibasic amino acid interactions with Na +-independent transport system asc in horse erythrocytes. Kinetic evidence of functional and structural homology with Na +-dependent system ASC

Amino acid transport in horse erythrocytes is regulated by three co-dominant allelomorphic genes coding for high-affinity transport activity (system asc 1), low-affinity transport activity (system asc 2) and transport-deficiency, respectively. The asc systems are selective for neutral amino acids of intermediate size, but unlike conventional system ASC, do not require Na + for activity. In the present series of experiments we have used a combined kinetic and genetic approach to establish that dibasic amino acids are also asc substrates, systems asc 1 and asc 2 representing the only mediated routes of cationic amino acid transport in horse erythrocytes. Both transporters were found to exhibit a strong preference for dibasic amino acids compared with neutral amino acids of similar size. Apparent K m values (mM) for influx via system asc 1 were l-lysine (9), l-ornithine (27), l-arginine (27), l-alanine (0.35). Corresponding V max estimates (mmol/l cells per h, 37°C) were l-lysine (1.65), l-ornithine (2.15), l-arginine (0.54), l-alanine (1.69). Apparent K m values for l-lysine and l-ornithine influx via system asc 2 were ≈ 90 and > 100 mM , respectively, with V max values > 2 and > 1 mmol/l cells per h, respectively. Apparent K m and V max values for l-alanine uptake by system asc 2 were 14 mM and 6.90 mmol/l cells per h. In contrast, l-arginine was transported by system asc 2 with the same apparent K m as l-alanine (14 mM), but with a 77-fold lower V max . This dibasic amino acid was shown to cause cis- and trans-inhibition of system asc 2 in a manner analogous to its interaction with system ASC, where the side-chain guanidinium group is considered to occupy the Na +-binding site on the transporter. Concentrations of extracellular l-arginine causing 50% inhibition of zero- trans l-alanine influx and half-maximum inhibition of l-alanine zero- trans efflux were 14 mM (extracellular l-alanine concentration 15 mM) and 3 mM (intracellular l-alanine concentration 15.5 mM), respectively. We interpret these observations as evidence of structural homology between the horse erythrocyte asc transporters and system ASC. Physiologically, intracellular l-arginine may function as an endogenous inhibitor of system asc 2 activity.

The Motor Vehicle - A Good Example of the Wide Range of Application of Modern Control Engineering

The paper briefly outlines current development activities concerning the use of active systems in automobile technology, particularly in the chassis/suspension field. Starting from the striking, pacesetting developments in engine control technology, similarly successful controls such as ABS and ASC systems, which influence vehicle dynamics are compared. Bearing in mind the necessary prerequisites for the successful utilization of modern control technology in the motor vehicle, the improvement potential and development trends in the field of chassis engineering are shown. The limitations of classic and the possibilities of modern control technology are demonstrated using the example of four-wheel steering and active suspension systems. The effects of these technologies will be perceptible over and above the individual automobile in future transport systems.

Alanine uptake by liver at midpregnancy in rats.

The participation of the liver to the increase in alanine utilization seen at midpregnancy was studied in 9- and 12-day pregnant rats. Liver fractional extraction of alanine was assessed in vivo from the changes in concentration in afferent and efferent vessels. Hepatic active transport of alanine was determined in vitro using isolated plasma-membrane vesicles. Compared with nonpregnant controls, alanine fractional extraction was significantly increased on day 12 but not on day 9 of pregnancy. Vesicles isolated from 9- and 12-day pregnant animals had a greater capacity for Na+-dependent transport than those from controls. Eadie-Hofstee plotting showed that this increase was due to an increase in Vmax with no change in Km. Both A and ASC systems contributed to the Vmax increase. These results indicate that, although by day 9 the liver has developed an increased capacity for alanine uptake, the actual extraction is seen only by day 12 of pregnancy. At this stage the liver participates actively in the turnover of alanine and the development of hypoalaninemia.

L-tyrosine and L-tryptophan transport in red blood cells in normal subjects. Effects of other amino acids, temperature and medium of incubation.

Blood cells may be used as a model in the central transport mechanisms of amino acids, precursors of amines, implicated in some hypotheses of psychiatric diseases. In a previous paper, we showed a deficit of tyrosine transport by red cells incubated in the plasma of depressed patients. In the present study, we have investigated the interaction of these peripheral transport mechanisms for tyrosine and tryptophan with other amino acid transports, such as the L and ASC systems, and the role of sodium ions in the extracellular medium. We also describe the inhibition induced by incubation at a low temperature, and a probable role of the membrane viscosity. The interest of incubating the cells in their own plasma, in order to have physiological conditions, is also discussed.

Uptake of valine and alanine by a neutral amino-acid carrier in sea urchin eggs: cyclic variations in the early cleavage stage

The characteristics of valine and alanine uptake (respectively, preferential substrates of the L and A or ASC systems in mammalian cells) were studied in sea urchin eggs before and 40 min after fertilization. Substrate concentration dependence showed that in unfertilized eggs alanine is absorbed linearly up to an external concentration of 20mm, whereas valine uptake presented a saturable kinetic with aKm of 6 μm. Competition experiments showed that valine is absorbed by a carriermediated transport resembling the L system. Fertilization develops a new Na-dependent system, resembling the ASC system which is specific for neutral amino acids but does not discriminate between them. This system is superimposed on that of the unfertilized egg. In fertilized eggs, amino-acid transport displayed cyclic variations which have been previously associated with cell cleavage. We have found that eggs prevented from cleavage by treatment with antimitotic undergo a sequence of periodic amino-acid uptake timed with the mitotic cycle of untreated eggs. In addition, artificially activated eggs (A23187) which failed to divide showed a time course of amino-acid uptake similar to that observed in fertilized eggs. Furthermore, these variations are independent of protein synthesis. These results suggest to us that a biological clock exists in the cytoplasm or cortex of sea urchin eggs, which may be involved in timing the cell cycle.

Carrageenin-induced arthritis. VI. Alterations in amino acid transport by articular cartilage in acute inflammatory arthritis.

The mechanism of transport of alanine and aminoisobutyric acid into chondrocytes in rabbit articular cartilage was shown to be mediated by transport systems similar to that described for other eukaryotic cells namely the A, ASC, and L systems. Three days after the initiation of an acute inflammatory arthritis by the intra-articular injection of carrageenin into one knee joint the rate of transport of both these amino acids was decreased. Although all three transport systems were depressed, it appeared that the A and ASC systems were partially susceptible to damage by the induced inflammation. The rate of amino acid transport by the affected cartilage had recovered by 28 days after carrageenin treatment. This depression in amino acid transport is discussed in relation to a decrease in general metabolic processes in chondrocytes as a consequence of inflammation.

Alanine-resistant mutants of Chinese hamster ovary cells, CHO-K1, producing increases in velocity of proline transport through the A, ASC, and P systems

We have developed a method for the isolation of transport mutants with increases in velocity of transport through the A and ASC systems and through a newly discovered P system utilizing the amino acid antagonism between A system amino acids and proline in CHO-K1 pro- cells. Mutants alar2 and alar3, isolated in a single-step procedure, resistant to 25 mM alanine in MEM-10 plus 0.05 mM proline are pro-, stable, cross resistant to alpha-(methylamino)isobutyric acid (MeAIB) and show an approximately twofold increase in the initial velocity of proline uptake. Ethyl methane sulfonate (EMS) increases the frequency of pro- alar clones in the population by at least 50 times the spontaneous frequency. The increased velocity of proline transport by alar2 and alar3 can be attributable to the 1.5 to 3 times increase in velocity of transport of proline through systems A, ASC, and P. The Vmax for proline transport through the A system has increased two times for alar2 while the Km and Vmax for alar3 has increased by 1.4 and 2.3 times that of CHO-K1. There is a corresponding increase in Vmax of proline transport by alar2 through the P system. The P system is defined operationally as that portion of the Na+-dependent velocity that remains when the A, ASC, and glutamine-inhibitable fraction are eliminated. The system is concentrative. Proline appears to be the preferred substrate. Li+ cannot be substituted for Na+. The system is moderately dependent upon pH. It obeys Michaelis-Menten kinetics and is not derepressible by starvation. There is no evidence for an N system in CHO-K1.

Growth regulation and amino acid transport in epithelial cells: Influence of culture conditions and transformation on A, ASC, and l transport activities

AbstractAmino acid transport in Madin‐Darby canine kidney (MDCK) cells, grown in a defined medium, was investigated as a function of cell density, exposure to specific growth factors, and transformation. MDCK cells were found to transport neutral amino acids by systems similar to the A, ASC, L, and N systems which have been characterized using other cell lines. Experimental conditions were developed for MDCK cells which allowed independent measurement of A, ASC, and L transport activities. The activity of the L system was measured as Na+‐independent leucine or methionine uptake at pH 7.4. The activity of the A system was measured as Na+‐dependent α(methylamino)isobutyric acid (mAIB) uptake at pH 7.4, the activity of the ASC system was measured as Na+‐dependent alanine uptake in the presence of 0.1 mM mAIB at pH 6.0, and the activity of system N was observed by measuring Na+‐dependent glutamine uptake at pH 7.4 in the presence of high concentrations of A and ASC system substrates. The L transport system responded minimally to changes in growth state, but Na+‐dependent amino add transport responded to regulation by growth factors, cell density, and transformation. The activities of the A and ASC systems both decreased at high cell density, but these activities responded dissimilarly under other conditions. The activity of the A system was stimulated by insulin, was inhibited by PGE1, and was elevated 3–7 fold in the transformed cell line, MDCK‐T1. The activity of the ASC system was slightly stimulated by insulin and by PGE1, but was unchanged after chemical transformation. Changes in cellular growth were monitored and were found to correlate best with the activity of the A system. These results suggested that MDCK cell growth may be more closely related to the activity of the A than of the ASC system.