2,960 research outputs found
Uptake of purines in <i>Plasmodium falciparum</i>-infected human erythrocytes is mostly mediated by the human Equilibrative Nucleoside Transporter and the human Facilitative Nucleobase Transporter
No full text<b>Background</b>: Plasmodium parasites are unable to synthesize purines de novo and have to salvage them from the host. Due to this limitation in the parasite, purine transporters have been an area of focus in the search for anti-malarial drugs. Although the uptake of purines through the human equilibrative nucleoside transporter (hENT1), the human facilitative nucleobase transporter (hFNT1) and the parasite-induced new permeation pathway (NPP) has been studied, no information appears to exist on the relative contribution of these three transporters to the uptake of adenosine and hypoxanthine. Using the appropriate transporter inhibitors, the role of each of these salvage pathways to the overall purine transport in intraerythrocytic Plasmodium falciparum was systematically investigated.
<b>Methods</b>: The transport of adenosine, hypoxanthine and adenine into uninfected and P. falciparum-infected human erythrocytes was investigated in the presence or absence of classical inhibitors of the hFNT1, hENT1 and NPP. The effective inhibition of the various transporters by the classical inhibitors was verified using appropriate known substrates. The ability of high concentration of unlabelled substrates to saturate these transporters was also studied.
<b>Results</b>: Transport of exogenous purine into infected or uninfected erythrocytes occurred primarily through saturable transporters rather than through the NPP. Hypoxanthine and adenine appeared to enter erythrocytes mainly through the hFNT1 nucleobase transporter whereas adenosine entered predominantly through the hENT1 nucleoside transporter. The rate of purine uptake was approximately doubled in infected cells compared to uninfected erythrocytes. In addition, it was found that the rate of adenosine uptake was considerably higher than the rate of hypoxanthine uptake in infected human red blood cells (RBC). It was also demonstrated that furosemide inhibited the transport of purine bases through hFNT1.
<b>Conclusion</b>: Collectively, the data obtained in this study clearly show that the endogenous host erythrocyte transporters hENT1 and hFNT1, rather than the NPP, are the major route of entry of purine into parasitized RBC. Inhibitors of hENT1 and hFNT1, as well as the NPP, should be considered in the development of anti-malarials targeted to purine transport
Perancangan Sistem Informasi Pengelola Barang/Inventaris Di Jc Komp
No full textInventory information system is a system used to enter inventory data into the database, so that there are no errors in input, output data, and reporting based on the desired data. based on surveys and interviews with jc comp personnel, information was obtained that the existing system in the jc comp warehouse section is still manual. therefore, the system that will be created by the author is the result of a replication of the existing system in the jc comp warehouse section. in addition to the process of input and output of goods, this information system is also equipped with features for creating data reports, input and output of goods, and searching for goods data by item name. with the inventory information system is expected to be useful for the warehouse parts jc comp. By implementing this system in the jc comp warehouse, it is hoped that it can reduce errors that may occur. this system is also expected to further speed up the process of input, output, and report generation, which in turn will help the jc comp warehouseSistem Informasi Persediaan Barang adalah sebuah sistem yang digunakan untuk memasukkan data-data persediaan barang ke dalam database, sehinggga tidak terjadi kesalahan dalam input, output data, dan pembuatan laporan berdasarkan data yang diinginkan. Berdasarkan survey dan wawancara dengan bagian personalia Jc Komp, didapatkan informasi bahwa sistem yang ada dibagian gudang Jc Komp masih manual. Oleh karena itu, sistem yang akan dibuat oleh penulis adalah hasil replikasi dari sistem yang telah ada dibagian gudang Jc Comp. Selain proses input dan output barang, pada sistem informasi ini juga dilengkapi fitur pembuatan laporan data, input, dan output barang, dan pencarian data barang berdasarkan nama barang. Dengan adanya Sistem Informasi persediaan barang ini diharapkan dapat bermanfaat bagi bagian gudang Jc Komp. Dengan diterapkannya sistem ini pada bagian gudang Jc Comp, maka diharapkan dapat mengurangi kesalahan-kesalahan yang mungkin terjadi. Sistem ini juga diharapkan dapat lebih mempercepat proses input, output, dan pembuatan laporan yang pada akhirnya dapat membantu bagian gudang Jc Komp
Amenable L-2-Theoretic Methods and Knot Concordance
No full textWe reveal new structures in the topological knot concordance group. As a key ingredient, we develop obstructions using L-2-theoretic methods for amenable groups in Strebel's class recently introduced by Orr and the author. Concerning (h)-solvable knots, which are defined in terms of certain Whitney towers of height h in bounding 4-manifolds, we show the following: for any n>1, there are (n)-solvable but non-(n. 5)-solvable (and therefore nonslice) knots, which are not detected by prior methods using Cochran-Orr-Teichner L-2-signature obstructions as well as Levine algebraic obstructions and Casson-Gordon invariants.X1197sciescopu
Dynamics of Network Formation Processes in the Co-Author Model
No full textThis article studies the dynamics in the formation processes of a mutual consent network in game theory setting: the Co-Author Model. In this article, a limited observation is applied and analytical results are derived. Then, 2 parameters are varied: the number of individuals in the network and the initial probability of the links in the network in its initial state. A simulation result shows a finding that is consistent with an analytical result for a state of equilibrium while it also shows different possible equilibria.Dynamics, Network, Game Theory, Model,Simulation, Equilibrium, Complexity
High-level polyomavirus JC viruria following long-term steroid therapy
No full textCASE REPORT JC virus is a highly seroprevalent ubiquitous polyomavirus which is acquired at an early age through respiratory or oral route, Thereafter JCV establishes persistent, but mainly asymptomatic, infections in various tissues, including the genitourinary tract and brain Corresponding author Cristina Costa, MD S.C.D.U. Virologia Azienda Ospedaliero-Universitaria San Giovanni Battista di Torino Via Santena, 9 -10126 Torino E-mail: [email protected] increasing with age, with adult prevalence rate often between 15% and 60
Engineering Framework to Utilize Miniaturized Charpy Type SE(B) Specimens to Predict Jc of Full Sized Specimens
No full textAbstractThis paper introduces our experience of using miniature Charpy type SE(B) specimen in obtaining fracture toughness Jc of a material in the ductile to brittle transition temperature (DBTT) region. Width W x thickness B of 2 x 2 mm, 3 x 3 mm and 10 x 10 mm were chosen as miniature specimens and 25 x 25 mm were chosen as full sized specimen. 0.55% carbon steel JIS S55C, whose tensile to yield stress ratio σTS/σYS was equal to 1.8 was chosen as a material to simulate a degraded (embrittled) material in the DBTT region. Focus was placed on whether cleavage fracture could be predicted for these miniaturized specimens. Another focus was placed on whether the Jc of full sized specimen is predictable from the test results of the miniature sized specimens, in case cleavage fracture were observed. The results showed that the modified Ritch-Knott-Rice (RKR) failure criterion (which predicts the onset of cleavage fracture when the crack opening stress measured at 4 times the crack-tip opening displacement exceeds this σ22c) could predict whether cleavage fracture would occur or not. Another finding was that, in case cleavage fracture was observed though, the critical value σ22c in the modified RKR failure criterion was independent of specimen size, and thus, Jc of the full sized specimen is predictable from the miniature specimen test results, though M = (W-a)σYS/Jc was smaller than ASTM E1921 requirement of 30. Here, a and σYS are crack length and yield strength, respectively
Monovalent cation leaks in human red cells caused by single amino-acid substitutions in the transport domain of the band 3 chloride-bicarbonate exchanger, AE1.
No full textAbstract
We identified 11 human pedigrees with dominantly inherited hemolytic anemias in both the hereditary stomatocytosis and spherocytosis classes. Affected individuals in these families had an increase in membrane permeability to Na and K that is particularly marked at 0 degrees C. We found that disease in these pedigrees was associated with a series of single amino-acid substitutions in the intramembrane domain of the erythrocyte band 3 anion exchanger, AE1. Anion movements were reduced in the abnormal red cells. The 'leak' cation fluxes were inhibited by SITS, dipyridamole and NS1652, chemically diverse inhibitors of band 3. Expression of the mutated genes in Xenopus laevis oocytes induced abnormal Na and K fluxes in the oocytes, and the induced Cl transport was low. These data are consistent with the suggestion that the substitutions convert the protein from an anion exchanger into an unregulated cation channel
Shifting attention in viewer- and object-based reference frames after unilateral brain injury
No full textThe aims of the present study were to investigate the respective roles that object- and viewer-based reference frames play in reorienting visual attention, and to assess their influence after unilateral brain injury. To do so, we studied 16 right hemisphere injured (RHI) and 13 left hemisphere injured (LHI) patients. We used a cueing design that manipulates the location of cues and targets relative to a display comprised of two rectangles (i.e., objects). Unlike previous studies with patients, we presented all cues at midline rather than in the left or right visual fields. Thus, in the critical conditions in which targets were presented laterally, reorienting of attention was always from a midline cue. Performance was measured for lateralized target detection as a function of viewer-based (contra- and ipsilesional sides) and object-based (requiring reorienting within or between objects) reference frames. As expected, contralesional detection was slower than ipsilesional detection for the patients. More importantly, objects influenced target detection differently in the contralesional and ipsilesional fields. Contralesionally, reorienting to a target within the cued object took longer than reorienting to a target in the same location but in the uncued object. This finding is consistent with object-based neglect. Ipsilesionally, the means were in the opposite direction. Furthermore, no significant difference was found in object-based influences between the patient groups (RHI vs. LHI). These findings are discussed in the context of reference frames used in reorienting attention for target detection
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