Dynamical Response of Nanomechanical Resonators to Biomolecular Interactions

We studied the dynamical response of a nanomechanical resonator to biomolecular (e.g. DNA) adsorptions on a resonator's surface by using a theoretical model, which considers the Hamiltonian H such that the potential energy consists of elastic bending energy of a resonator and the potential energy for biomolecular interactions. It was shown that the resonant frequency shift of a resonator due to biomolecular adsorption depends on not only the mass of adsorbed biomolecules but also the biomolecular interactions. Specifically, for dsDNA adsorption on a resonator's surface, the resonant frequency shift is also dependent on the ionic strength of a solvent, implying the role of molecular interactions on the dynamic behavior of a resonator. This indicates that nanomechanical resonators may enable one to quantify the biomolecular mass, implying the enumeration of biomolecules, as well as gain insight into intermolecular interactions between adsorbed biomolecules on the surface.Comment: 17 page, 4 figures, accepted for publication at PRB. Physical Review B, accepte

Ammonium Inhibits Chromomethylase 3-Mediated Methylation of the Arabidopsis Nitrate Reductase Gene NIA2

Gene methylation is an important mechanism regulating gene expression and genome stability. Our previous work showed that methylation of the nitrate reductase (NR) gene NIA2 was dependent on chromomethylase 3 (CMT3). Here, we show that CMT3-mediated NIA2 methylation is regulated by ammonium in Arabidopsis thaliana. CHG sequences (where H can be A, T, or C) were methylated in NIA2 but not in NIA1, and ammonium [(NH4)2SO4] treatment completely blocked CHG methylation in NIA2. By contrast, ammonium had no effect on CMT3 methylation, indicating that ammonium negatively regulates CMT3-mediated NIA2 methylation without affecting CMT3 methylation. Ammonium upregulated NIA2 mRNA expression, which was consistent with the repression of NIA2 methylation by ammonium. Ammonium treatment also reduced the overall genome methylation level of wild-type Arabidopsis. Moreover, CMT3 bound to specific promoter and intragenic regions of NIA2. These combined results indicate that ammonium inhibits CMT3-mediated methylation of NIA2 and that of other target genes, and CMT3 selectively binds to target DNA sequences for methylation

Development of Barley Cultivars for Animal Forage in Korea

In Korea, the domestic consumption of barley as a cereal crop has been decreasing since the 1980s. It has been considered that crop production in the winter-season rice fields could enhance the global competitiveness of domestic livestock industry by providing better quality fodder to livestock and enhancing field use rate. Therefore, the purpose of barley cultivation for cereal food production has been recently replaced by the production of the barley for forage use. Consequently, the area of barley cultivation for forage is markedly increasing in Korea. While any type of barley can be used as forage for feeding cattle, whole crop barley delivers a higher dry matter yield than conventional feed barley. This paper described the present state of forage barley cultivars developed in Korea

Extracellular matrixes and neuroinflammation

The extracellular matrix is a critical component of every human tissue. ECM not only functions as a structural component but also regulates a variety of cellular processes such as cell migration, differentiation, proliferation, and cell death. In addition, current studies suggest that ECM is critical for the pathophysiology of various human diseases. ECM is composed of diverse components including several proteins and polysaccharide chains such as chondroitin sulfate, heparan sulfate, and hyaluronic acid. Each component of ECM exerts its own functions in cellular and pathophysiological processes. One of the interesting recent findings is that ECM is involved in inflammatory responses in various human tissues. In this review, we summarized the known functions of ECM in neuroinflammation after acute injury and chronic inflammatory diseases of the central nerve systems

DESIGN OF THE 4 MeV RFQ FOR THE HELIUM BEAM IRRADIATOR*

Abstract A radio frequency quadrupole (RFQ) is considered as a main accelerator of the helium beam irradiation system for the power semiconductor in Korea Multipurpose Accelerator Complex (KOMAC) The RFQ was designed to accelerate the He2+ beam up to 4 MeV with 10 mA peak beam current. We chose a vane type RFQ with 200 MHz operating frequency. The RFQ will be operated with the frequency tracking mode supplied by the digital low level RF control system. In this paper, the design of the 4 MeV RFQ is presented and the beam irradiation system including RF system, control system, utility system, is discussed

Effects of creatine and β-guanidinopropionic acid and alterations in creatine transporter and creatine kinases expression in acute seizure and chronic epilepsy models

<p>Abstract</p> <p>Background</p> <p>In order to confirm the roles of creatine (Cr) in epilepsy, we investigated the anti-convulsive effects of Cr, creatine transporter (CRT) and creatine kinases (CKs) against chemical-induced acute seizure activity and chronic epileptic seizure activity.</p> <p>Results</p> <p>Two hr after pilocarpine (PILO)-seizure induction, ubiquitous mitochondrial CK (uMtCK) immunoreactivity was unaltered as compared to control level. However, brain-type cytoplasm CK (BCK) immunoreactivity was decreased to 70% of control level. CRT immunoreactivity was decreased to 60% of control level. Following Cr or Tat-CK treatment, uMtCK or CRT immunoreactivity was unaffected, while BCK immunoreactivity in Cr treated group was increased to 3.6-fold of control levels. β-Guanidinopropionic acid (GPA, a competitive CRT inhibitor) reduced BCK and CRT expression. In addition, Cr and tat-BCK treatment delayed the beginning of seizure activity after PILO injection. However, GPA treatment induced spontaneous seizure activity without PILO treatment. In chronic epilepsy rats, both uMtCK and CRT immunoreactivities were reduced in the hippocampus. In contrast, BCK immunoreactivity was similar to that observed in control animals. Cr-, GPA and tat-BCK treatment could not change EEG.</p> <p>Conclusion</p> <p>Cr/CK circuit may play an important role in sustaining or exacerbating acute seizure activity, but not chronic epileptic discharge.</p

Development of EKC after Eximer Laser Photorefractive Surgery and Subsequent Recurrence of EKC-like Keratitis

This research focuses on four cases of patients having undergone eximer laser photorefractive surgery who were diagnosed with adenoviral keratoconjunctivitis during the postoperative period and who later developed epidemic keratoconjunctivitis (EKC)-like keratitis. Two of the patients had undergone laser-assisted subepithelial keratectomy (LASEK), one had undergone laser in situ keratomileusis and one had photorefractive keratectomy. After the surgery adenoviral keratoconjunctivitis and recurrent late-developing EKC-like keratitis were observed in the patients. Recurrent late-developing EKC-like keratitis occurred in one of the patients, who had received LASEK as many as three times. The others had only one or two episodes.The corneal infiltrates of keratitis mainly occurred in the central cornea. Successful resolution of recurrent late-developing EKC-like keratitis was achieved through the use of topical steroids without sequelae and the final best-corrected visual acuity was as good as the base line. These keratitis infiltrates have been presumed to represent an immune response to the suspected adenoviral antigens deposited in corneal stroma during the primary adenoviral infection. Previous reports argued that patients with a history of adenoviral ketatoconjunctivitis were succeptible to adenoviral keratoconjunctivitis becoming reactivated; however, in our research, our patients had their first adenoviral infections after the eximer laser photorefractive surgery and reactivation was confirmed. We recommend that attention be paid to adenoviral infection after laser refractive operations, because these patients seem to have more frequent recurrences

Safety and Effectiveness of the Novel Catheter 3.0 System for Diagnostic Cerebral Angiography: A Pilot Study

Purpose The purpose of this study was to evaluate the safety and effectiveness of a new angiographic system (Catheter 3.0 system) using a 5 French (Fr), large-bore angiography catheter, a 0.032-inch stiff guidewire, and a continuous flushing system in diagnostic cerebral angiography. Materials and Methods This retrospective study included 30 consecutive patients who underwent transfemoral cerebral angiography using the Catheter 3.0 system from October 2019 to March 2020. As the control group, we included 30 consecutive patients examined before the Catheter 3.0 system was introduced. Procedural outcomes, including technical success, procedure time, dose metrics, procedure-related complications, and image quality were reviewed and analyzed. Results All transfemoral cerebral angiographies were performed for a diagnosis of unruptured intracranial aneurysms. The Catheter 3.0 system showed a significantly shorter fluoroscopy time (6.2 vs. 9.7 minutes, P=0.008) and lower fluoroscopy dose (387.2 vs. 614.4, P=0.002) compared with the conventional 4-Fr catheter system. The Catheter 3.0 system also showed better results in terms of procedural time (21.0 vs. 22.5 minutes, P=0.072) and technical success rate (98.1% vs. 94.0%, P=0.078), although a statistical significance was not reached. The complication rate and qualitative assessment of the digital subtraction angiography (DSA) image quality were similar between the two groups. Conclusion The Catheter 3.0 system using a 5 Fr catheter with a large inner diameter was convenient, effective, and safe compared with the conventional system in diagnostic cerebrovascular angiography