739 research outputs found

    Shoot multiplication of Paphiopedilum orchid through in vitro cutting methods

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    Paphiopedilum orchids are generally propagated through the division of axillary buds from mother plant, which limits commercial production due to its unproductive proliferation and time consuming. In this study, the effect of in vitro cutting methods and medium composition on efficient shoot multiplication of Paphiopedilum Hsinying Rubyweb was investigated. Among three different in vitro stem cutting methods used, vertical cutting was able to produce more new shoots than horizontal and cross cutting when cultured on Hyponex based medium. After 12 weeks of culture, plantlets regenerated from vertical cutting were able to produce new healthy and well rooted shoots higher than without cutting on the same medium. Moreover, the newly-formed shoots which were divided into single plantlets and subcultured onto half-strength Murashige and Skoog (MS) medium without growth regulators could remain higher shoot multiplication than in other media. The micropropagation procedure developed in this study provides a simple means to in vitro propagate Paphiopedilum plantlets which are able to produce large numbers of uniform plantlets in a shorter time compared to the conventional propagation method.Key words: Micropropagation, shoot multiplication, cutting, Paphiopedilum

    Asymptotic stability and generalized Gelfand spectral radius formula

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    AbstractLet ∑ be a set of n × n complex matrices. For m = 1, 2, …, let ∑m be the set of all products of matrices in ∑ of length m. Denote by ∑′ the multiplicative semigroup generated by ∑. ∑ is said to be asymptotically stable (in the sense of dynamical systems) if there is 0 < α < 1 such that there are bounded neighborhoods U, V ⊂ Cn of the origin for which AV ⊂ αmU for all A ∈ ∑m, m = 1, 2, …. For a bounded set ∑ of n × n complex matrices, it is shown that the following conditions are mutually equivalent:(i) ∑ is asymptotically stable; (ii) \̂g9(∑) = lim supm → ∞[supA ∈ ∑m ‖ A ‖]1/m < 1; (iii) ϱ(∑) = lim supm → ∞[supA ∈ ∑m ϱ(A)]1/m < 1, where ϱ(A) stands for the spectral radius of A; and (iv) there exists a positive number α such that ϱ(A) ⩽ α < 1 for all A ∈ ∑′. This fact answers an open question raised by Brayton and Tong. The generalized Gelfand spectral radius formula, that is, ϱ(∑) = \̂g9(∑), conjectured by Daubechies and Lagarias and proved by Berger and Wang using advanced tools from ring theory and then by Elsner using analytic-geometric tools, follows immediately form the above asymptotic stability theorem

    Eighth graders&apos; web searching strategies and outcomes: The role of task types, web experience and epistemological beliefs

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    Abstract This study reported an investigation of eighth graders&apos; (14-year-olds) web searching strategies and outcomes, and then analyzed their correlations with students&apos; web experiences, epistemological beliefs, and the nature of searching tasks. Eighty-seven eighth graders were asked to fill out a questionnaire for probing epistemological beliefs (from positivist to constructivist-oriented views) and finished three different types of searching tasks. Their searching process was recorded by screen capture software and answers were reviewed by two expert teachers based on their accuracy, richness and soundness. Five quantitative indicators were used to assess students&apos; searching strategies: number of keywords, visited pages, maximum depth of exploration, refinement of keyword, and number of words used in the first keyword. The main findings derived from this study suggested that, students with richer web experiences could find more correct answers in &apos;&apos;closeended&quot; search tasks. In addition, students with better metacognitive skills such as keyword refinement tended to achieve more successful searching outcomes in such tasks. However, in &apos;&apos;open-ended&quot; tasks, where questions were less certain and answers were more elaborated, students who had more advanced epistemological beliefs, concurring with a constructivist view, had better searching outcomes in terms of their soundness and richness. This study has concluded that epistemological beliefs play an influential role in open-ended Internet learning environments

    A 5-Month-Old Infant with Right Scrotum Swelling

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    Case presentation:A five-month-old male infant (gestational age 28 weeks, birthweight 1020 gm) with posthemorrhagic hydrocephalus subsequent to prematurity had a left sided ventriculoperitoneal shunt 3 months after birth. Frontal radiography of the chest and abdomen check-up after operation are shown in figure 1. He was referred to our emergency department with a history of right scrotal swelling for several days. Physical examination, he appeared malnourished. He was afebrile. The right scrotum was found to be distended. Bilateral testicles were palpable on both sides. There were no features of shunt malfunction. A complete blood cell count showed the following: leukocyte count, 7900/mm3; segmented neutrophils, 65%; hemoglobin level of 9.3 mg/dL; hematocrit, 25.9%; and platelet, 190000/uL. Other laboratory studies included: glucose, 92 mg/dL; serum urea nitrogen, 10 mg/dL; serum creatinine, 0.2 mg/dL; sodium, 140 mEq/L; potassium, 3.9 mEq/L; C-reactive protein, 2.9mg/L; and prothrombin time with an international normalized ratio of 1.2. His abdomen x-ray is shown in figure 2. 

    The 3D-tomography of the nano-clusters formed by Fe-coating and annealing of diamond films for enhancing their surface electron field emitters

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    [[abstract]]The Fe-coating and H2-annealed processes markedly increased the conductivity and enhanced the surface electron field emission (s-EFE) properties for the diamondfilms. The enhancement on the s-EFE properties for the diamondfilms is presumably owing to the formation of nano-graphite clusters on the surface of the films via the Fe-to-diamond interaction. However, the extent of enhancement varied with the granular structure of the diamondfilms. For the microcrystalline (MCD)films, the s-EFE process can be turned on at (E0)MCD = 1.9 V/μm, achieving a large s-EFE current density of (Je)MCD = 315 μA/cm2 at an applied field of 8.8 V/μm. These s-EFE properties are markedly better than those for Fe-coated/annealed ultrananocrystalline diamond(UNCD)films with (E0)UNCD = 2.0 V/μm and (Je)UNCD = 120 μA/cm2. The transmission electron microscopy showed that the nano-graphite clusters formed an interconnected network for MCDfilms that facilitated the electron transport more markedly, as compared with the isolated nano-graphitic clusters formed at the surface of the UNCDfilms. Therefore, the Fe-coating/annealing processes improved the s-EFE properties for the MCDfilms more markedly than that for the UNCDfilms. The understanding on the distribution of the nano-clusters is of critical importance in elucidating the authentic factor that influences the s-EFE properties of the diamondfilms. Such an understanding is possible only through the 3D-tomographic investigations.[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]電子版[[countrycodes]]US

    Apoptosis induction in BEFV-infected Vero and MDBK cells through Src-dependent JNK activation regulates caspase-3 and mitochondria pathways

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    Our previous report demonstrated that bovine ephemeral fever virus (BEFV)-infected cultured cells could induce caspase-dependent apoptosis. This study aims to further elucidate how BEFV activates the caspase cascade in bovine cells. BEFV replicated and induced apoptosis in Vero and Madin-Darby bovine kidney (MDBK) cells, and a kinetic study showed a higher efficiency of replication and a greater apoptosis induction ability of BEFV in Vero cells. Src and c-Jun N-terminal kinase (JNK) inhibitor, but not extracellular signal-regulated kinase (ERK) or p38 inhibitor, alleviated BEFV-mediated cytopathic effect and apoptosis. In BEFV-infected Vero and MDBK cells, BEFV directly induced Src tyrosine-418 phosphorylation and JNK phosphorylation and kinase activity, which was inhibited specifically by SU6656 and SP600125, respectively. The caspase cascade and its downstream effectors, Poly (ADP-ribose) polymerase (PARP) and DFF45, were also activated simultaneously upon BEFV infection. In addition, cytochrome c, but not Smac/DIABLO, was released gradually from mitochondria after BEFV infection. SU6656 suppressed Src, JNK, and caspase-3 and -9 activation, as well as PARP and DFF45 cleavage; SP600125 reduced JNK and caspase-3 and -9 activation, as well as PARP and DFF45 cleavage. Taken together, these results strongly support the hypothesis that a Src-dependent JNK signaling pathway plays a key role in BEFV-induced apoptosis. The molecular mechanism identified in our study may provide useful information for the treatment of BEFV

    Effects of Functional Electrical Stimulation on Peak Torque and Body Composition in Patients with Incomplete Spinal Cord Injury

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    The aim of this study was to investigate the change in body composition, leg girths, and muscle strength of patients with incomplete spinal cord injury (SCI) after functional electrical stimulation cycling exercises (FESCE). Eighteen subjects with incomplete SCI were recruited. Each patient received FESCE three times per week for 8 weeks. Body composition, thigh and calf girths of bilateral legs, muscle strength of bilateral knee flexors and extensors were measured before and after 4 and 8 weeks of FESCE. A significant increase in bilateral thigh girth after 4 weeks of FESCE and significant increase in muscular peak torque of knee flexion and extension were found after 8 weeks of training. Besides, lean body mass increased significantly after complete treatment. FESCE can increase the thigh girth and muscular peak torque of patients with incomplete spinal cord injury

    Spleen artery embolization increases the success of nonoperative management following blunt splenic injury

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    AbstractBackgroundSpleen artery embolization (SAE) may increase the success rate of nonoperative management (NOM). The present study investigated the clinical outcome after the installation of SAE in the management of blunt splenic injury.MethodsA retrospective review of hospital records was performed to enroll patients with blunt injury of the spleen. Demographic data and information about the injury severity score, organ injury scale, hospitalization days, management and final outcomes were evaluated. Patients were separated into early and late groups according to the year that SAE was selectively used (2003–2004 and 2005–2008).ResultsSix of eleven (55%) patients in the early group were successfully managed without surgery for blunt splenic injury, whereas all of the 38 patients (100%) in the late group were successfully managed without surgery. Eleven patients (11 of 38; 28.9%) received SAE in the late group. The rate of NOM increased from 55% in the early group to 100% in the late group (p < 0.001). Both early and late groups had similar injury severity score, length of hospitalization, blood transfusion, and complications, and there was no mortality.ConclusionPerformance of SAE for the patients with blunt splenic injury could increase the successful rate of NOM significantly and safely. An algorithm including the angioembolization might be beneficial in the management of patients with blunt spleen trauma
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