497 research outputs found

    Palladium Catalysts for Dehydrogenation of Ammonia Borane with Preferential Bāˆ’H Activation

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    Cationic Pd(II) complexes catalyzed the dehydrogenation of ammonia borane in the most efficient manner with the release of 2.0 equiv of H_2 in less than 60 s at 25 Ā°C. Most of the hydrogen atoms were obtained from the boron atom of the ammonia borane. The first step of the dehydrogenation reaction was elaborated using density functional theory calculations

    Intra- and inter-hemispheric effective connectivity in the human somatosensory cortex during pressure stimulation

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    Background: Slow-adapting type I (SA-I) afferents deliver sensory signals to the somatosensory cortex during low-frequency (or static) mechanical stimulation. It has been reported that the somatosensory projection from SA-I afferents is effective and reliable for object grasping and manipulation. Despite a large number of neuroimaging studies on cortical activation responding to tactile stimuli mediated by SA-I afferents, how sensory information of such tactile stimuli flows over the somatosensory cortex remains poorly understood. In this study, we investigated tactile information processing of pressure stimuli between the primary (SI) and secondary (SII) somatosensory cortices by measuring effective connectivity using dynamic causal modeling (DCM). We applied pressure stimuli for 3 s to the right index fingertip of healthy participants and acquired functional magnetic resonance imaging (fMRI) data using a 3T MRI system. Results: DCM analysis revealed intra-hemispheric effective connectivity between the contralateral SI (cSI) and SII (cSII) characterized by both parallel (signal inputs to both cSI and cSII) and serial (signal transmission from cSI to cSII) pathways during pressure stimulation. DCM analysis also revealed inter-hemispheric effective connectivity among cSI, cSII, and the ipsilateral SII (iSII) characterized by serial (from cSI to cSII) and SII-level (from cSII to iSII) pathways during pressure stimulation. Conclusions: Our results support a hierarchical somatosensory network that underlies processing of low-frequency tactile information. The network consists of parallel inputs to both cSI and cSII (intra-hemispheric), followed by serial pathways from cSI to cSII (intra-hemispheric) and from cSII to iSII (inter-hemispheric). Importantly, our results suggest that both serial and parallel processing take place in tactile information processing of static mechanical stimuli as well as highlighting the contribution of callosal transfer to bilateral neuronal interactions in SII.open1

    Phytohormone abscisic acid control RNA-dependent RNA polymerase 6 gene expression and post-transcriptional gene silencing in rice cells

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    RNA-dependent RNA polymerase 6 (RDR6) catalyses dsRNA synthesis for post-transcriptional gene silencing (PTGS)-associated amplification and the generation of endogeneous siRNAs involved in developmental determinations or stress responses. The functional importance of RDR6 in PTGS led us to examine its connection to the cellular regulatory network by analyzing the hormonal responses of RDR6 gene expression in a cultured cell system. Delivery of dsRNA, prepared in vitro, into cultured rice (Oryza sativa cv. Japonica Dongjin) cells successfully silenced the target isocitrate lyase (ICL) transcripts. Silencing was transient in the absence of abscisic acid (ABA), while it became persistent in the presence of ABA in growth medium. A transcription assay of the OsRDR6 promoter showed that it was positively regulated by ABA. OsRDR6-dependent siRNA(ICL) generation was also significantly up-regulated by ABA. The results showed that, among the five rice OsRDR isogenes, only OsRDR6 was responsible for the observed ABA-mediated amplification and silencing of ICL transcripts. We propose that ABA modulates PTGS through the transcriptional control of the OsRDR6 gene

    Interferometric detection of prostate specific antigen based on enzyme immunoassay

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    AbstractInterferometric detection of Prostate-specific antigen (PSA) based on enzyme immunoassay are investigated. Refractive index changes of substrate are measured for PSA detection. Michelson scheme of optical interferometer was used so as to be applicable to a disposable fluidic chip. When interferometer is used for the measurements of refractive index changes, the detection is over 8 times more sensitive than that of absorbance changes for the same amount of target protein

    Somatic Mutations from Whole Exome Sequencing Analysis of the Patients with Biliary Tract Cancer

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    Biliary tract cancer (BTC) is a rare cancer and is associated with a poor prognosis. To understand the genetic characteristics of BTC, we analyzed whole-exome sequencing data and identified somatic mutations in patients with BTC. Tumors and matched blood or normal samples were obtained from seven patients with cholangiocarcinoma who underwent surgical resection. We discovered inactivating mutations of tumor suppressor genes, including APC, TP53, and ARID1A, in three patients. Activating mutations of KRAS and NRAS were also identified. Our analyses identified somatic mutations in Korean patients with BTC

    Anesthetic management of penetrating neck injury patient with embedded knife -A case report-

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    Penetrating neck injuries can be a fatal event and they are difficult to manage for both surgeons and anesthesiologists. So, adequate preoperative evaluation is important to improve the patients' outcomes, but this can not be done for hemodynamically unstable or uncooperative patient. Here we present our clinical experience with a patient with a penetrating neck injury and who was hemodynamically stable, but she was uncooperative and the knife was still embedded in her neck. The surgical exploration and bronchoscopic examination were successfully done under monitored anesthesia care

    Anticholinesterase Therapy for Patients with Ophthalmoplegia Following Snake Bites: Report of Two Cases

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    Although ophthalmoplegia following snake bites is not indicative of a serious neurotoxic complication, symptoms of diplopia, dizziness and ocular discomfort can be emotionally devastating for patients. The authors experienced two cases of ophthalmoplegia following snake bites in Korea. The patients complained of diplopia that had developed several hours after the snake bites. The diplopia did not improve with antivenom treatment, but resolved completely after several injections of neostigmine
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