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        검색결과 44

        3.
        2022.09 구독 인증기관·개인회원 무료
        Potato is an important cash crop of Pakistan and widely cultivated in plains and mountains of Punjab. Khyber Pakhtun Khawa Gilgit Baltistan, on an area of 0.313 million hectares in summer, autumn and spring with an annual production of 07.9 million tons. In Pakistan potato yield is 25.2 tons per hectare, which is although above the world average but comparatively low as compare to the potential and other advance potato growing countries because of several reasons. Availability of healthy seeds and advance production technology are the major constraints to achieve the higher potato production goals. It is very alarming that in spite of good position in potato growing countries, we are unable to produce good quality seed. In Pakistan >01% quality seed is available against the seed demand around 0.5-0.7 million tons per annum and mostly depend upon the imported seed 15000-20000 tons per annum. Tissue culture industry has been a proven global technology in potato seed production, so it is dire need of the growing population and climatic change to adopt these modern technologies of potato production for sustainable and higher production and income to contribute potato growing farmers of Pakistan. It is possible with the commercial use of tissue culture and allied techniques as aeroponic potato seed production along with good management and plant protection measures to provide indigenous high vigor and high yield potential potato seed. Pakistan Agricultural Research Council has established Aeroponic Potato Seed Production facility at National Agricultural Research Center with the collaboration of Korean Govt RDA-KOPIA Pakistan. The Aeroponics is a modern technology for growing plants by providing a nutrient solution in the air without soil. Plants grow rapidly in the growth chamber under the aseptic environment, balanced nutrition and sufficient oxygen availability that improves potatoes production in the aeroponic system. This can produce 10 times more yield than conventional production systems. Aeroponics techniques are credited for making potato yield more efficient, and can reduce the number of steps in the potato seed multiplication. Through tissue culture and aeroponics facilities development in Pakistan, first ever more than 200,000 nucleus mini harvested at NARC from the autumn 2021 and spring 2022 planation at KOPIA screen houses. Further seed multiplication from the harvest is under progress at up hills and more than 500,000 tubers (G1) are expected to be harvested during October-November 2022. It is very encouraging, impressive and successful venture of KOPIA at Pakistan for the potato seed production and self-sufficiency to insure food security in the country.
        4.
        2022.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Cloud-aerosol interactions are one of the paramount but least understood forcing factors in climate systems. Generally, an increase in the concentration of aerosols increases the concentration of cloud droplet numbers, implying that clouds tend to persist for longer than usual, suppressing precipitation in the warm boundary layer. The cloud lifetime effect has been the center of discussion in the scientific community, partly because of the lack of cloud life cycle observations and partly because of cloud problems. In this study, the precipitation susceptibility (So) matrix was employed to estimate the aerosols' effect on precipitation, while the non-aerosol effect is minimized. The So was calculated for the typical coupled, well-mixed maritime stratocumulus decks and giant cloud condensation nucleus (GCCN) seeded clouds. The GCCN— artificially introduced to the marine stratocumulus cloud decks—is shown to initiate precipitation and reduces So to approximately zero, demonstrating the cloud lifetime hypothesis. The results suggest that the response of precipitation to changes in GCCN must be considered for accurate prediction of aerosol-cloud-precipitation interaction by model studies
        4,500원
        5.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to find out that how much does it effects as it considered not only animal additive genetic effect but also maternal genetic effect for improving litter traits of pigs. The data of 10,836 records on 2,636 sows in Landrace and 14,463 records on sows in Yorkshire were analyzed which had been measured from 1998 to July 2017 in a nucleus herd of pig population. The traits used on this analysis were total number of born with (TNB2) and without mummy (TNB1) and number of born alive (NBA). Two different multivariate animal mixed models were considered and compared of variance components estimated from these models. The one (Model 1) was set up with assumed to parity, return events and batch effects as fixed and service sire, permanent environment and animal additive genetic effects as random. The other (Model 2) was same with Model 1 except considering maternal additive genetic effects as random. (Co)variance for random effects and genetic parameters were estimated using restricted maximum likelihood method and breeding values as best linear unbiased prediction were estimated using preconditioned conjugate gradient algorithm on each model and breed. From these models, heritability estimates for NBA were about 0.10 and 0.11 on both models in Landrace and Yorkshire, respectively. Forthermore, it was estimated that there were little variations in the maternal genetic effects with roughly 1~2% of total variation. Result from comparing estimated breeding values for each trait between each model, ranking of genetic capability through total breeding values on model 1 and on model 2 showed highly correlated with more than 0.92. Consequently, for improving litter traits, selection based on breeding values by direct genetic effects without considering maternal genetic effects were reccommendable.
        4,000원
        6.
        2016.09 구독 인증기관 무료, 개인회원 유료
        The ultrastructural parameters related to synaptic release of endings which are presynaptic to tooth pulp afferent terminals (p-endings) were analyzed to understand the underlying mechanism for presynaptic modulation of tooth pulp afferents. Tooth pulp afferents were labelled by applying wheat-germ agglutinin conjugated horseradish peroxidase to the rat right lower incisor, whereafter electron microscopic morphometric analysis with serial section and reconstruction of p-endings in the trigeminal oral nucleus was performed. The results obtained from 15 p-endings presynaptic to 11 labeled tooth pulp afferent terminals were as follows. P-endings contained pleomorphic vesicles and made symmetrical synaptic contacts with labeled terminals. The p-endings showed small synaptic release-related ultrastructural parameters: volume, 0.82 ± 0.45 μm3 (mean ± SD); surface area, 4.50 ± 1.76 μm2; mitochondrial volume, 0.15 ± 0.07 μm3; total apposed surface area, 0.69 ± 0.24 μm2; active zone area, 0.10 ± 0.04 μm2; total vesicle number, 1045 ± 668.86; and vesicle density, 1677 ± 684/μm2. The volume of the p-endings showed strong positive correlation with the following parameters: surface area (r=0.97, P<0.01), mitochondrial volume (r=0.56, P<0.05), and total vesicle number (r=0.73, P<0.05). However, the volume of p-endings did not positively correlate or was very weakly correlated with the apposed surface area (r=-0.12, P=0.675) and active zone area (r=0.46, P=0.084). These results show that some synaptic release-related ultrastructural parameters of p-endings on the tooth pulp afferent terminals follow the “size principle” of Pierce and Mendell (1993) in the trigeminal nucleus oralis, but other parameters do not. Our findings may demonstrate a characteristic feature of synaptic release associated with p-endings.
        4,000원
        7.
        2015.12 구독 인증기관 무료, 개인회원 유료
        Neuronal activities of taste-responsive cells in the nucleus of the solitary tract (NST) are affected by various physiological factors, such as blood glucose level or sodium imbalance. These phenomena suggest that NST taste neurons are under the influence of neural substrates that regulate nutritional homeostasis. In this study, we reviewed a series of in vivo electrophysiological investigations that demonstrate that forebrain nuclei, such as the lateral hypothalamus or central nucleus of the amygdala, send descending projections and modulate neuronal activity of gustatory neurons in the NST. These centrifugal modulations may mediate plasticity of taste response in the NST under different physiological conditions.
        4,000원
        8.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recognition of the role of radio galaxies in the universe has been increasing in recent years. Their colossal energy output over huge volumes is now widely believed to play a key role not only in the formation of galaxies and their supermassive black holes, but also in the evolution of clusters of galaxies and, possibly, the cosmic web itself. In this regard, we need to understand the in ation of radio bubbles in the hot gas atmospheres of clusters and the importance of the role that radio galaxies play in the overall energy budget of the intracluster medium. Here, we present results from X-ray and radio band observations of the hot gas atmospheres of powerful, nearby radio galaxies in poor clusters.
        4,000원
        9.
        2015.03 구독 인증기관 무료, 개인회원 유료
        Sucrose and alcohol are rewarding and appetitive. They are occasionally over-consumed and cause addiction. The parabrachial nuclei (PbN) are the second taste relay in the central taste pathway. The nucleus accumbens (NAcc) is an important neural substrate in the reward system. Intake of sucrose or alcohol induces dopamine release in the NAcc. Although alcohol is not classified as a taste stimulus, a substantial number of sucrose-responsive neurons in the PbN respond to stimulation by alcohol on the tongue. In the present study, we investigated whether or not application of 0.5 M sucrose, 10% ethanol (EtOH), mixture of sucrose and EtOH, and double-distilled water (DDW) to the tongue induces c-Fos-like immunoreactivity (cFLI) in the PbN and NAcc. We also examined whether or not the number of cFLI following sucrose/EtOH is comparable to the number of cFLIs following sucrose and EtOH, respectively. Male Sprague-Dwaley rat was anesthetized with a mixture of Zoletil and Rompun while stimulation solution was applied to the anterior tongue. The rat was sacrificed by perfusion, and the fixed brain was sectioned and immunostained. Data from a total of 18 animals were analyzed. The number of cFLI following stimulation with sucrose and/or EtOH was greater than that of DDW in the PbN. Numbers of cFLI following sucrose, EtOH, and sucrose/EtOH were not significantly different from each other in the PbN. The number of cFLI in response to stimulation solution was not different from that of DDW in the NAcc. The result of the present study suggests that not only sucrose but also EtOH activates some neurons in the PbN, and that some pontine neurons possibly respond to both sucrose and EtOH.
        4,000원
        10.
        2013.04 구독 인증기관·개인회원 무료
        11.
        2013.03 구독 인증기관 무료, 개인회원 유료
        Taste receptors of the anterior tongue are innervated by the chorda tympani (CT) branch of the facial (VIIth) nerve. The CT nerve transmits information on taste to the ipsilateral nucleus of the solitary tract (NST), which is the first taste central nucleus in the medulla. Taste information is known to be transferred ipsilaterally along the taste pathway in the central nervous system. Some patients with unilateral CT damage often retain their ability to sense taste. This phenomenon is not explained by the unilateral taste pathway. We examined whether neurons in the NST receive information on taste from the contralateral side of the tongue by measuring c-Fos-like Immunoreactivity (cFLI) following taste stimulation of the contralateral side of the tongue in the anesthetized rats. We used four basic taste stimuli, 1.0 M sucrose, 0.3 M NaCl, 0.01 M citric acid, 0.03 M QHCl, and distilled water. Stimulation of one side of the tongue with taste stimuli induced cFLI in the NST bilaterally. The mean number of cFLI ranged from 23.28 ± 2.46 by contralateral QHCl to 30.28 ± 2.26 by ipsilateral NaCl stimulation. The difference between the number of cFLI in the ipsilaterl and contralateral NST was not significant. The result of the current study suggests that neurons in the NST receive information on taste not only from the ipsilateral but also the contralateral side of the tongue.
        4,000원
        12.
        2011.06 구독 인증기관 무료, 개인회원 유료
        Using whole cell current- and voltage-clamp recording we investigated the characteristics and pharmacology of group I metabotropic glutamate receptor (mGluR)-mediated responses in rat medial vestibular nucleus (MVN) neurons. In current clamp conditions, activation of mGluR I by application of the group I mGluR agonist (R,S)-3,5-dihydroxyphenylglycine (DHPG) induced a direct excitation of MVN neurons that is characterized by depolarization and increased spontaneous firing frequency. To identify which of mGluR subtypes are responsible for the various actions of DHPG in MVN, we used two subtype-selective antagonists. (S)-(+)- alpha-amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist that is selective for mGluR5. In voltage clamp conditions, DHPG application increased the frequency of spontaneous and miniature inhibitory postsynaptic currents (IPSCs) but had no effect on amplitude distributions. Antagonism of the DHPG-induced increase of miniature IPSCs required the blockade of both mGluR1 and mGluR5. DHPG application induced an inward current, which can be enhanced under depolarized conditions. DHPG-induced current was blocked by LY367385, but not by MPEP. Both LY367385 and MPEP antagonized the DHPG-induced suppression of the calcium activated potassium current (IAHP). These data suggest that mGluR1 and mGluR5 have similar roles in the regulation of the excitability of MVN neurons, and show a little distinct. Furthermore, mGluR I, via pre- and postsynaptic actions, have the potential to modulate the functions of the MVN.
        4,000원
        13.
        2009.12 구독 인증기관 무료, 개인회원 유료
        Medial vestibular nucleus (MVN) neurons are involved in the reflex control of the head and eyes, and in the recovery of vestibular function after the formation of peripheral vestibular lesions. In our present study, whole cell patch clamp recordings were carried out on MVN neurons in brainstem slices from neonatal rats to investigate the actions of a group I metabotropic glutamate receptor (mGluR) agonist upon synaptic transmission and ionic currents. Application of the mGluR I agonist (S)-3,5- dihydroxyphenylglycine (DHPG) increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs) but had no effect upon amplitude distributions. To then identify which of mGluR subtypes is responsible for the actions of DHPG in the MVN, we employed two novel subtype selective antagonists. (S)-(+)--amino-a-methylbenzeneacetic acid (LY367385) is a potent competitive antagonist that is selective for mGluR1, whereas 2-methyl-6-(phenylethynyl)-pyridine (MPEP) is a potent noncompetitive antagonist of mGluR5. Both LY367385 and MPEP antagonized the DHPG-induced increase of mIPSCs, with the former being more potent. DHPG was also found to induce an inward current, which can be enhanced under depolarized conditions. This DHPG-induced current was reduced by both LY367385 and MPEP. The DHPG-induced inward current was also suppressed by the PLC blocker U-73122, the IP₃ receptor antagonist 2-APB, and following the depletion of the intracellular Cα2+ pool by thapsigargin. These data suggest that the DHPG-induced inward current may be mainly regulated by the intracellular Cα2+ store via the PLC-IP3 pathway. In conclusion, mGluR I, via pre- and postsynaptic actions, may modulate the excitability of the MVN neurons.
        4,000원
        17.
        2006.12 구독 인증기관 무료, 개인회원 유료
        In the primary sensory neuron of the mesencephalic trigeminal nucleus (MTN), the peripheral axon supplies a large number of annulospiral endings surrounding intrafusal fibers encapsulated in single muscle spindles while the central axon sends only a few number of synapses onto single α-motoneuron₃.(α-MN₃)Therefore, the α-y linkage is thought to be very crucial in the jaw-closing movement. Spike activity in a y-motoneuron (y-MN) would induce a large number of impulses in single peripheral axons by activating many intrafusal fibers simultaneously, subsequently causing an activation of α-MN₃ in spite of the small number of synapses. Thus, the activity of y-MN₃ may be vital for modulation of jaw-closing movements. Independently of such a spindle activity modulated by y-MN₃, somatic depolarization in MTN neurons is known to trigger the oscillatory spike activity. Nevertheless, the trafficking of these spikes arising from the two distinct sources of MTN neurons is not well understood. In this short review, switching among multiple functional modes of MTN neurons is discussed. Subsequently, it will be discussed which mode can support the α-y linkage. In our most recent study, simultaneous patch-clamp recordings from the soma and axon hillock revealed a spike-back-propagation from the spike-initiation site in the stem axon to the soma in response to a somatic current pulse. The persistent Nα+ current was found to be responsible for the spike-initiation in the stem axon, the activation threshold of which was lower than those of soma spikes. Somatic inputs or impulses arising from the sensory ending, whichever trigger spikes in the stem axon first, would be forwarded through the central axon to the target synapse. We also demonstrated that at hyperpolarized membrane potentials, 4-AP-sensitive K+ current (IK₄_AP) exerts two opposing effects on spikes depending on their origins; the suppression of spike initiation by increasing the apparent electrotonic distance between the soma and the spike-initiation site, and the facilitation of axonal spike invasion at higher frequencies by decreasing the spike duration and the refractory period. Through this mechanism, the spindle activity caused by y-MN₃would be safely forwarded to α-MN. Thus, soma spikes shaped differentially by this IK₄_AP depending on their origins would reflect which one of the two inputs was forwarded to the target synapses.
        4,000원
        18.
        2005.09 구독 인증기관 무료, 개인회원 유료
        Gamma-aminobutyric acid (GABA) is known as an inhibitory neurotransmitter in the neurons of the central nervous system. However, its detailed action mechanisms in the rostral gustatory zone of the nucleus tractus solitarius (rNTS) have not been established. The present study was aimed to investigate the distribution, role and action mechanisms of GABA in rNTS. Membrane potentials were recorded by whole cell recordings in isolated brain slices of the rat medulla. Superfusion of GABA resulted in a concentration-dependent reduction in input resistance in the neurons in rNTS. The change in input resistance ws accompanied by response to a depolarizing pulse were diminished by GABA. Superfusion of the slices with either GABAд agonist, muscimol, GABAв agonist, baclofen or GABAс agonist, TACA, decreased input resistance and reduced the nerve activity in association with membrane hyperpolarization. It is suggested that inhibitory signals playa role in sensory processing by the rNTS, in that GABA actions occur through activation of GABAд,GABAв and GABAс receptor. These results suggest that GABA has an inhibitory effect on the rNTS through an activation of GABAд ,GABAв and GABAсreceptors and that the GABAergic inhibition probably plays an important role in sensory processing by the rNTS.
        4,000원
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