Top PDF Recruitment of Perisomatic Inhibition during Spontaneous Hippocampal Activity In Vitro.

Recruitment of Perisomatic Inhibition during Spontaneous Hippocampal Activity In Vitro.

Recruitment of Perisomatic Inhibition during Spontaneous Hippocampal Activity In Vitro.

addition to multi-unit activity. In keeping with recently published data, these events likely correspond to the GABA-A receptor (GABA-A R) mediated synaptic currents evoked in their pyramidal target population by the synchronous release of GABA from the multiple synaptic terminals of perisomatically projecting interneu- rons. First, they often (41620%, n = 12 cells from 8 animals) correlated with inhibitory postsynaptic signals from an individual pyramidal cell recorded intracellularly (Fig. 1B), their kinetics (rise time 2.0660.47 ms, mono-exponential decay time constant 5.2362.56 ms, n = 3578 and 3292 events respectively, from 6 animals, Fig. 1F) were similar to those of GABA-A mediated IPSCs, and they showed reversed polarity in the stratum radiatum (Fig. 1A) as reported for basket and chandelier cells mediated events [21,22]. Second, they persisted in the presence of the glutamatergic NMDA and AMPA/KA receptor antagonists, APV (100 m M) and NBQX (10 m M) or DNQX (5 m M), which did not significantly change their amplitudes (49.8614.9 m V in control, 44.3610.2 m V in APV+NBQX/CNQX, n = 5 recordings from 3 rats, p.0.05, paired Student’s T test) although their frequency decreased by 75% from 3.7761.4 to 1.3961.6 events/s (n = 5 recordings from 3 rats, p,0.05, paired Student’s T test, Fig. 1D). Third, they were not observed in presence of the selective GABA- A R antagonist bicuculline (20 m M, n = 3). Indeed, glutamatergic activity alone (indicated by both intense extracellular multi-unit activity and patch-clamp whole-cell recordings in the presence of bicuculline) did not produce such LFPs (Fig. 1E). Fourth, application of diazepam (10 m M), which selectively prolongs the decay of GABA-A R mediated synaptic currents [24], produced a 70% increase of average decay time constants for eIPSPs (from 5.8162.54 to 9.8764.28 ms, p,0.05, n = 5045 and 2726 events respectively, from 4 slices), indicating that they are indeed mediated by GABA-A R (Fig. 1F). And finally, as also reported previously [21,22], recording intracellularly from interneurons whose somata were located in or adjacent to the pyramidal layer, we occasionally (n = 11 cells) found neurons in which firing of a single action potential was sufficient to evoke an eIPSP in the extracellular record over distances of several tens of m m (Fig. 1C). Among five eIPSP triggering interneurons filled with either biocytin or neurobiotin, three could be successfully processed for morphological and immunocytochemical analysis. All showed typical basket cell morphology, with perisomatic axonal projection and positive immuno-staining for parvalbumin but not for somatostatin (Fig. 2A,B). As illustrated in Fig. 2A,C, eIPSPs evoked by these interneurons were recorded within but not outside their axonal projection area. And as expected from monosynaptic GABAergic transmission, they displayed short latency (0.5860.39 ms, n = 683 events, Fig. 2H,I).
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In vitro dose-dependent inhibition of the intracellular spontaneous calcium oscillations in developing hippocampal neurons by ketamine.

In vitro dose-dependent inhibition of the intracellular spontaneous calcium oscillations in developing hippocampal neurons by ketamine.

0.04260.006 Hz and 2.0160.07, respectively. This study showed that 100 m M MNDA did not have any statistically significant effect on the frequency of the calcium oscillations, but did induce a significant increase in the amplitude of the calcium oscillations. In addition, the application of 40 m M MK801 could induce a significant inhibition of the amplitude and frequency of the calcium oscillations. However, Sinner et al. demonstrated that the same dose of MK801 caused a complete inhibition of the calcium oscillations [26]. We hypothesize that, in addition to the differences in the methods used for the cell culture and the measurement of the calcium oscillations, this inconsistency is mainly due to the different developmental stages of the study subjects. The cells used in our study were at the critical period for the formation of synaptic connections; these cells were neurons at the rapid developmental stage, and the experiment was performed on the fifth day of in vitro culture. In contrast, Sinner et al. used hippocampal neurons cultured for 17–18 days in vitro; at this time, the hippocampal neurons are substantially mature and/or nearly aging. NMDAR is a heterotetramer that consists of different types of subunits: NR1, NR2, and NR3. During different developmental stages of the central nervous system, the expression of NMDAR subunits is also different [27,28]. For example, the expression of the NR1 subunit can be found in 14-day-old rat embryos, reaches its peak in postnatal week 3, and then gradually decreases over time to the adult level [29]. The expression of NR2 reaches its peak in postnatal week 3 and is then gradually reduced to the adult level [30]. NR3 is mainly expressed in the developing central nervous system, which also exhibits temporal scalability [31]. Different NMDAR subtypes are involved in different physiological processes [32,33]; this may thus be the main reason responsible for the different experimental results. Our experimental model confirmed that NMDARs definitely participate and play a pivotal role in the formation of cytosolic calcium oscillations in neurons. These results provide an experimental basis for our subsequent studies on another intravenous anesthetic, ketamine, which is a non-competitive NMDA antagonist.
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Blockade of persistent sodium currents contributes to the riluzole-induced inhibition of spontaneous activity and oscillations in injured DRG neurons.

Blockade of persistent sodium currents contributes to the riluzole-induced inhibition of spontaneous activity and oscillations in injured DRG neurons.

Figure 3. Effects of riluzole on the spontaneous activity and SMPOs of A-type neurons in the compressed DRG. (A) Intracellullar sharp electrode recordings from an A-type DRG neuron in vivo, showing spontaneous activity and SMPOs under control conditions (a), after local application of riluzole (80 mM; b,c), and during washout (d). The spikes have been truncated. Inserted segments (a–d, lower panel) are expansions of the original traces at the times indicated and show details of the spikes and SMPOs. (B) Whole-cell patch recordings from an A-type DRG neuron in vitro . Spontaneous activity (a) was significantly inhibited in the presence of riluzole (10 mM; b,c) and restored after washout (d). The spikes have been truncated. Inserted segments (a–d, lower panel) are expansions of the original traces at the times indicated. (C) Whole-cell patch recordings from an A-type DRG neuron in vitro. (a) The cell responded to depolarizing current pulses of 1.7 nA (upper panel) and 2.4 nA (lower panel) with repetitive firing and SMPOs (insertion). (b) In the presence of 10 mM riluzole (upper panel), both the repetitive firing and SMPOs (insertion) induced by depolarization were abolished; however, a single action potential was still evoked immediately after application of the current pulse.
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In Vitro Assessment of Antileishmanial Activity of

In Vitro Assessment of Antileishmanial Activity of

individually or in combination with other drugs, has not been studied against L. donovani. Several factors such as mechanism of action against fungi i.e. binding with ergosterol and causing pores in the cell membrane, easy availability, very less toxicity as compared to amphotericin B and approval for human use prompted us to select these two drugs. In the present study, we have evaluated the effectiveness of natamycin and nystatin in vitro against the promastigote forms of L. donovani, the most common species of Leishmania found in India. We have observed that nystatin is able to inhibit the growth of parasite within 24 hours of administration with an IC 50 value of 105.7μg/ml. In a similar study, the in vitro antileishmanial activities of
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Patterns of enzymatic activity of cell wall-modifying enzymes during growth and ripening of apples

Patterns of enzymatic activity of cell wall-modifying enzymes during growth and ripening of apples

Fig. 3. Patterns of non-pectolytic enzymatic activities accessed during growth and ripening of ‘Mondial Gala’ apples using the assays described in Section 2. (1) Fruit-set; (2) growing fruit; (3) unripe, fully expanded fruit; (4) fruit at harvest; (5) over-ripe fruit; NC, negative control (boiled enzyme extract with 10% SDS). Values represent the mean ± S.D. of six replicates per assay, except for the expansin assay in which n = 4. Letters represent statistical significance at 1%.

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Functional structure of spontaneous sleep slow oscillation activity in humans.

Functional structure of spontaneous sleep slow oscillation activity in humans.

To characterize the propagation across the scalp of each SSO event, we estimated three features. 1) The extent of propagation, corresponding to the number of detected SSOs in the event. 2) The extent of propagation in the area – i.e., considering 4 main scalp areas, the number of detections per area normalized to the number of electrodes in the same area. The four main areas were defined as follows: frontal (Fp1, Fp2, F3, F4, Fz, F8, F7), central (FC3, FC4, C3, Cz, C4, CP3, CPz, CP4), temporal (FT7, FT8, T3, T4, TP7, TP8, T5, T6) and posterior (P3, Pz, P4, PO1, PO2, O1, Oz, O2). 3) The speed of propagation. The event speed was estimated resting on the assumption of the simplest propagation model: SSOs radially propagate from their event origin location, forming circular fronts like a stone thrown in a pond. The event origin location, i.e. the location from which the propagating SSO originates was detected searching for the channel containing the first occurring negative peak. Also the propagation delays were estimated by the latency between the negative peaks (precisely detectable since usually sharp and not crowned by oscillations in the spindle frequency range [5]).
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ALTERNATIVE PRODUCTS IN THE “IN VITRO” INHIBITION OF Sclerotinia sclerotiorum

ALTERNATIVE PRODUCTS IN THE “IN VITRO” INHIBITION OF Sclerotinia sclerotiorum

ABSTRACT: The white mold, caused by Sclerotinia sclerotiorum, is a very important disease in tomato crops. The objective of this work was to study the effect of plant extracts, animal residues and industrial by- products extracts on the fungus in vitro growth. Treatments consisted of different concentrations of pyrolignous oil, neem oil, monosodium glutamate, sewage sludge and organic compost [coffee residue (50%) coal residue (10%), maize residue (25%), poultry waste (12.5%), poultry meal (2.5%)]. Positive control consisted of Petri dishes with PDA medium and negative control treatment consisted of PDA medium with procymidone. Fungus colonies were incubated at 22ºC and light intensity of 260 lux. Variables such as mycelium growth rate, sclerotia production, and viability 7 and 17 days after the transfer of mycelium disc to neon media were assessed. The extract of organic compost at 30% was effective in controlling mycelial growth and sclerotia production. This treatment, as well as neem oil at 0.5% increased soil respiration.
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Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

Determination Of Longevity Of Teeth In Buckets Of Loading Equipment In Coal Mines - A Case Study

Abstract: The life of bucket teeth in shovel and dragline deployed in handling of overburden rock is an important contributor to the stores cost and is also responsible for the loss of valuable availability and utilisation time of these critical equipment. To ascertain the effect of rock type on longevity of bucket teeth, a study has been conducted in two large opencast mines of Singrauli Coalfields. The results of this study is presented in this paper. There was a significant variation as compared to the actual figures of the mine, it establish useful relationship between the type of mineral present in the overburden and the life of bucket teeth of shovel and dragline.
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In Vitro Inhibition of Adhesion of Escherichia coli Strains by

In Vitro Inhibition of Adhesion of Escherichia coli Strains by

For both the E. coli strains, at all the three concentrations of xylitol, there was a significant reduction of microbial adhesion. The results indicated that xylitol’s mechanism of action was based on preventing the bacterial adherence. Other studies in the literature also support this anti- adherent hypothesis. Söderling and Hietala- Lenkkeri (2010) found that 4% xylitol inhibited glass adhesion of six oral streptococci strains, which indicated that xylitol could contribute to decrease the plaque accumulation. These authors also observed that the adherence mechanism was not dependent on the growth inhibition. Ammouns et al. (2009) found the 5% xylitol could prevent biofilm formation, in vitro, of a wound clinical isolated strain of Pseudomonas aeruginosa. Kontiokari et al. (1998) evaluated the adherence of microorganisms in the presence of 5% xylitol which prevented the Streptococcus pneumoniae adhesion, and, in a lesser proportion, the Haemophilus influenza adhesion. Tapiainen et al. (2004) observed changes in the capsule and cell wall of Streptococcus pneumoniae after exposure to xylitol (0.5 - 5.0% in two hours). The cell wall became more diffused and the polysaccharide capsule became rougher. The phenotype of all the strains tested, before exposure to sugar, was opaque and almost became transparent during the experiment. It was suggested that the ability of xylitol to change the structure of bacteria was responsible for inhibiting the adhesion and, therefore, for the changes in microorganisms virulence.
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RNA Interference: a Promising Therapy for Gastric Cancer

RNA Interference: a Promising Therapy for Gastric Cancer

produced by small double-stranded RNAs which include endogenous microRNA (miRNA) and exogenous small interfering RNA (siRNA) or short hairpin RNA (shRNA). These are all commonly cleavage by endogenous enzyme called Dicer that gives rise to the important transcription factors involved in the gene expression regulation. This methodology’s greatest potential is to speciically repress the transcription of disease-causing genes thus avoiding undesirable effects. This is possible due to the fact that RNAi acts exclusively on the endogenous mechanism called RNA induced silecing complex (RISC) which acts as an endonuclease on target messenger RNA (mRNA). Thus, the gene expression is controlled at the post-transcriptional level through the recognition and cleavage of mRNA in association with RISC (Baulcombe, 2000; Matzke et al., 2001; Bader et al., 2010; Wilson and Plucinski, 2011). Figure 1 shows a simpliied scheme of the functioning mechanism of RNAi.
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In Vitro Study of Vellozia pusilla Pohl (Velloziaceae), a Brazilian Plant Species: Antitumoral Activity and Labeling of Blood Elements

In Vitro Study of Vellozia pusilla Pohl (Velloziaceae), a Brazilian Plant Species: Antitumoral Activity and Labeling of Blood Elements

Vellozia pusilla Pohl is a species of the botanic family Velloziaceae that occurs in the subtropical regions of South America and, although it lives under conditions of high solar irradiation and low water availability, shows great longevity. The methanol extract of roots, stem and leaf sheaths of this species showed an antitumoral activity through the inhibition of the enzyme Topoisomerase I when analyzed by an in vitro bioassay employing DNA repair or recombination deficient mutants of the yeast Saccharomyces cerevisiae. In the evaluation of the effect of Vellozia pusilla methanol extract on the labeling of RBC, blood of mice was treated with 99mTc tracer solutions. The percentage of radioactivity (%ATI) bound to plasma (P) and blood cells (BC) was determined. The %ATI in the insoluble fraction of plasma (IF) was also evaluate, and the results showed that there was a decrease in %ATI in this fraction that represents the plasmatic proteins.
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Inhibition of NKCC1 attenuated hippocampal LTP formation and inhibitory avoidance in rat.

Inhibition of NKCC1 attenuated hippocampal LTP formation and inhibitory avoidance in rat.

This experiment was carried out to determine the blockage effect of bumetanide on inhibitory avoidance learning is on short- term memory or long-term memory formation. Sixteen animals were randomly distributed to two groups and received drug administration similar to experiment-1. An extra short-term memory test was taken place in 1 hr after training. Animals were then returned to their housing cage and subject for the 2 nd test 24 hrs after training. Bumetanide treated rats showed normal inhibitory avoidance learning in the short-term memory test. Rats Figure 1. Superfusion of bumetanide blocked the formation of hippocampal LTP in a dose dependent manner. (A) From Left to right, representative superimposed traces of fEPSPs recorded extracellularlly under control conditions and after exposure to 0, 5, 10, and 20 mM bumetanide. Application of 10 mM bumetanide blocked LTP formation in hippocampus CA1 Schaffer collateral fiber. Bumetanide was applied from 2 10 min,10 min. n = 10 for each trial (B) fEPSP recorded in the stratum radiatum and evoked by stimulation of the Schaffer collateral—commissural pathway with different intensities in vehicle-treated and bumetanide-treated slices (10 mM). fEPSP slopes are comparable between vehicle-treated (filled circle, n = 8) and bumetanide-treated (open circle, n = 8) for a given range of stimulus intensities. (C) Fiber volley amplitudes are similar between vehicle-treated and bumetanide-treated (10 mM) slices for a given range of stimulus intensities.
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Alterations in spontaneous brain oscillations during stroke recovery.

Alterations in spontaneous brain oscillations during stroke recovery.

After preprocessing the data, the amplitude spectra of sponta- neous brain activity were calculated separately for the eyes-open and eyes-closed conditions by averaging the magnitudes of fast Fourier transforms (FFT) in half-overlapping windows over the whole measurement time. To estimate the amplitudes of spontaneous brain oscillations in the frequency range of 5– 90 Hz, 2048-point FFTs, corresponding to a frequency resolution of ,0.5 Hz were used. A flat-top window was applied in conjunction with the FFTs to get accurate amplitude estimates from the spectra. To identify possible ALFMA (0–4 Hz), 8192- point FFTs, resulting in a frequency-resolution of ,0.1 Hz, with a Hanning window were used. A Hanning window was chosen for its better frequency resolution compared to the flat-top window. The amplitudes of the spectral peaks over the centroparietal (rolandic 10-Hz and beta rhythms) and parieto–occipital (alpha rhythm) regions were quantified from 5–9 MEG channels showing the largest amplitudes (see Fig. 1).
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Sustained spindle-assembly checkpoint response requires de novo transcription and translation of cyclin B1.

Sustained spindle-assembly checkpoint response requires de novo transcription and translation of cyclin B1.

continuous Cyclin B1 degradation model [13]. This model has been proposed based on the observation of a slow but continuous proteasome-dependent proteolysis of Cyclin B, in the presence of an active SAC. In the presence of microtubule targeting drugs SAC cannot be satisfied and bypassing an active SAC requires proteasome-mediated proteolysis of Cyclin B1 to escape mitosis. The continuous degradation model proposes that, in vertebrate cells, the SAC would not efficiently block all APC/Cs from ubiquitinating Cyclin B, leading to a gradual drop of Cyclin B until it reaches a level lower than the needed to maintain the mitotic delay [13]. We extend this model and propose that the decrease in the Cyclin B1 mRNA levels observed in our data by inhibition of transcription may contribute to a further decrease in the levels of the protein pool, additional to that caused by the leakage proteolysis. Upon inhibition of transcription, the minimal threshold of Cyclin B1 needed to maintain the mitotic delay is more rapidly reached, resulting in the activation of the APC/ C Cdc20 and the consequent active ubiquitination of Cyclin B1 and Securin, targeting these substrates for proteasome degradation. This hypothesis is further substantiated with our observation that inhibition of proteasome degradation does not prevent the decrease of Cyclin B1 mRNA levels upon inhibition of transcription, despite preventing the decrease of protein levels. Therefore, upon inhibition of proteasome degradation, inhibition of transcription or translation has no impact in the levels of Cyclin B1 protein pool, and accordingly, mitotic slippage no longer occurs.
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Analysis of neutrophil recruitment during tissue regeneration in zebrafish models of human disease

Analysis of neutrophil recruitment during tissue regeneration in zebrafish models of human disease

In an attempt to analyze the progression of neutrophil recruitment the average of the normalized fluorescence intensity values from the first region of each time-point were used for statistical analysis (Figure 3.21). As shown in the results there were no statistically significant differences between time- points, and this was most likely due to the normalization applied as in the visual analysis there was a clear difference in the recruitment to the injury area between the 6 hpi and 3 dpi time-points for example. Another important factor to be taken into consideration when characterizing neutrophil recruitment is the extension of the injury as a natural variation in the size of the injuries is expected from a manually performed procedure. The quantification of the extension of the initial injury could have been used to determine if the discrepant intensity values on the same time-point were due to a different injury size, as larger infarctions are expected to require more prolonged inflammatory and wound healing processes. The size of the visible injured area in the ventricle was determined in relation to total ventricle area to get an estimate of the extension of the damage. The earliest time-points, 6 hpi and 1dpi, had the smallest visibly injured areas and the largest were at 3 dpi. This was expected in the early time- points neutrophils had just arrived and the inflammatory response was beginning, having to wait until 3 days after the injury to be able to see the full extension (González-Rosa et al., 2011). The reduction in the visible injured area at 7 dpi could be due to just variation or from progression of the regenerative process. Overall, this means the visible infarction area values determined at 6 hpi and 1 dpi were underestimated, since the heart damage could not be detected with the HE staining or IHC antibodies used. An anti-fibronectin antibody might have been a good addition to the IHC as it could have been used to label the injury area in the later time-points, even possibly allowing the addition of an automated selection of the injury area during the script analysis. However, a possible concern with the use of this antibody would have been the tissue formed around the ventricle detected at 3dpi, which was of fibrotic nature and therefore rich in fibronectin.
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Synthesis Of Arts In Architecture Of Uzbekistan Of The Ancient Period

Synthesis Of Arts In Architecture Of Uzbekistan Of The Ancient Period

for accommodation of bas-relief panels [34]. So, there were no regularities to install the sculptures and "the whole sculpture was seen as one of the kinds of inner decor of the wall" [35, 81p]. According to G.A. Pugachenkova, the tradition of placing the royal statues in separately designated locations began from the era of Kanishka (in Surkh-Kotal the statues were located in inter- columnar spans) and presented a stylistic feature of the monumental art of late antiquity. In the "Hall of Kings" in Toprak-Kala, according to S.P. Tolstov, was a portrait gallery of Khoresm Siyavushids, "huge seated statues depicted the kings and the surrounding statues –their family members, and god-protectors" [36, 109p]. The isolated location of the figures symbolized the coming disintegration of the dynasty. However, it should be noted that "round sculpture, especially of large forms had no such strong roots in Central Asia" [3, 231p], as monumental painting, common even before the Hellenistic conquest. Wall and high relief compositions had dominated, particularly in the design of Buddhist monuments (stupas).
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Increase in Hippocampal Theta Oscillations during Spatial Decision Making

Increase in Hippocampal Theta Oscillations during Spatial Decision Making

Recent results suggest that hippocampal activity also sup- ports memory-guided decisions in humans. A functional neuro- imaging study has shown that hippocampal activity increases when subjects retrieve goal location in a virtual maze (Viard et al., 2011). In temporal areas, theta oscillations are modu- lated by contextual and spatial decision tasks, and also correlate with memory retrieval (Kahana et al., 1999; Guitart-Masip et al., 2013). In addition, theta power was reported to increase in parieto-temporal areas when subjects correctly recognize pre- viously presented items (Osipova et al., 2006). The capacity to forecast the successful mnemonic retrieval of word lists based on hippocampal theta oscillations recorded during encoding also suggests that theta oscillations may reflect cognitive proc- esses in the hippocampus (Kahana et al., 1999; Sederberg et al., 2003). Additionally, there is a functional overlap between memory retrieval and future thinking, which is associated with the activity of hippocampal networks (Hassabis et al., 2007; Schacter et al., 2007). In all, our results showing the emergence of strong theta activity in the hippocampus when memory- guided spatial decisions are required suggest that theta oscilla- tions support the retrieval of rewarded choices. However, as it is also the case for other LFP rhythms (Kay et al., 2009), it remains to be determined whether theta oscillations play a mechanistic role in cognition, or are only epiphenomena of the neuronal computations carried out by the hippocampus. In addition, it also remains to be determined whether the hippo- campus per se engages, or is engaged by, other brain regions involved in DM such as the prefrontal cortex (Siapas et al., 2005, Guitart-Masip et al., 2013).
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Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Investigating The Use Of Mobile Computing In Zimbabwe Polytechnics Case Of A Polytechnic In Zimbabwe

Zimmerman (1999) in his article titled ―Mobile Computing: Characteristics, Benefits, and the Mobile fra mework‖ defined mobile computing as ―the use of computing devices, which usually interact in some way with a centralised information system while away from the normal fixed workplace‖. He went on to say that, Mobile computing technology enables the mobile person to create, access, process, store and communicate information without being constrained to a single location. It is on the above basis that this researcher views mobile computing as embracing a host of portable technologies the can access internet using wireless fidelity (WIFI). These range from notebook computers to tablets, to smartphones and e-book readers. Such devices have brought about Mobile learning (m-Learning) in Zimbabwe Polytechnics, enabling staff and students to share academic resources, be able to research and develop applications from wherever they are. Zimmerman (1999) went on to identify mobile computing hardware, software and communications in use then. He identified hardware as palmtops, clamshells, handheld Pen Keys, pen slates, and laptops. The characteristics of such devices in terms of screen size was small, processing capability was limited and supported a few mobile applications. Over the years mobile devices have improved in such characteristics to make mobile computing easy, fast and user friendly. Great improvements also came with the associated systems software, with the modern devices now running on Android, Symbian and windows 8 mobile, as compared to then when MS DOS, Windows 3.1, Pen DOS were used. In communications Zimmerman talked of internet speeds in kilobytes per second (Kbps), while today’s communications devices have speeds of gigabytes per second (Gbps
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Renata Moschini Daudt4 , Gustavo Ramalho Cardoso dos Santos5 , Nilo Sérgio Medeiros Cardozo4 and Ana Lúcia Ponte Freitas1

Renata Moschini Daudt4 , Gustavo Ramalho Cardoso dos Santos5 , Nilo Sérgio Medeiros Cardozo4 and Ana Lúcia Ponte Freitas1

Based on the strain sweep tests performed to determine the region linear viscoelastic behavior of the samples in the dynamic oscillatory tests, the frequency sweep (FS) tests were carried out at 8% of a deformation. The results of the FS tests are presented in Figure 6, where it can be seen that the values of loss modulus (G”) were higher than those of the storage modulus (G’) at all concentrations and frequencies tested. These results indicate that the extracted polysaccharide fraction does not lead to gel-like solutions. This behavior can be attributed to the elevated amount of sulfate that was observed in the polysaccharide obtained by papain digestion. The structure of agarans is strongly influenced by the presence of charged groups that participate in intermolecular hydrogen bonds [48] ; the strength of this
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Selective PDE4 inhibitors as potent anti-inflammatory drugs for the treatment of airway diseases

Selective PDE4 inhibitors as potent anti-inflammatory drugs for the treatment of airway diseases

coded by 4 genes (Conti & Jin 1999), which are al- ternatively spliced in different variants 1, 2, 3 (2, 3, 4, 5, 6). Two different structures of these variants can be dis- tinguished, short forms (65-75 kDa) and long forms (80- 130 kDa). The difference between short and long forms lies in the N-terminal region, at the level of UCR1 and UCR2 (upstream conserved regions): short forms are trun- cated at UCR2 and long forms have both UCR1 and UCR2 (Bolger et al. 1997). The different PDE4 subtypes are dif- ferently expressed depending on the tissue. PDE4A is expressed in all tissues except in neutrophils (Wang et al. 1999), PDE4B is widely expressed and is the pre-dominant PDE4 subtype in monocytes and neutrophils (Wang et al. 1999), but lacks in cortex and epithelial cells (Jin et al. 1998), PDE4C is absent from circulating inflammatory cells, cortex and hippocampus and has been detected in lung and testis (Obernolte et al. 1997, Manning et al. 1999, Martin-Chouly et al. 2004) and PDE4D is particularly ac- tive in lung, cortex, cerebellum and T cells (Erdogan & Houslay 1997, Jin et al. 1998). The up-regulations of the PDE4B subtype in response to pro-inflammatory agents suggest that PDE4B could be particularly involved in in- flammatory processes. However, by screening a large num- ber of PDE4 inhibitors against the recombinant human enzyme, it has been able to identify a few selective sub- type inhibitors (Manning et al. 1999). The results obtained using these kinds of compounds suggest that PDE4A and or PDE4B may play the major role in regulating LPS-in- duced TNF- α release and T-cell proliferation but do not rule out PDE4D as an important mediator of other activi- ties in mononuclear leukocytes and other immune and inflammatory cells (Manning et al. 1999, Jin & Conti 2002). Using an in vitro model of DMSO-treated HL60 cells, we found a change of PDE4 subtype profile during differen- tiation (Jacob et al. 2002). PDE4B was the predominant isoenzyme, PDE4D was down-regulated and PDE4A was no longer detectable. Additionally, the more NADPH oxi- dase was activated by PMA, the less PDE4A was ex- pressed, suggesting that NADPH oxidase activity could be used as a surrogate marker of PDE4A down-regula- tion. Rolipram and Ariflo (cilomilast), two selective PDE4 inhibitors, dose-dependently inhibited receptor-coupled activation of superoxide. These results suggest that PDE4B is the main subtype involved in regulating super- oxide induced by immune complex activation. Further- more, these cells, expressing almost exclusively PDE4B subtype, could be useful to identify selective PDE4B in- hibitors (Jacob et al. 2002).
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