Hybrid star HD 81817 accompanied by brown dwarf or substellar companion

HD 81817 is known as a hybrid star. Hybrid stars have both cool stellar wind properties and Ultraviolet (UV) or even X-ray emission features of highly ionized atoms in their spectra. A white dwarf companion has been suggested as the source of UV or X-ray features. HD 81817 has been observed since 2004 as a part of a radial velocity (RV) survey program to search for exoplanets around K giant stars using the Bohyunsan Observatory Echelle Spectrograph at the 1.8 m telescope of Bohyunsan Optical Astronomy Observatory in Korea. We obtained 85 RV measurements between 2004 and 2019 for HD 81817 and found two periodic RV variations. The amplitudes of RV variations are around 200 m s^-1, which are significantly lower than that expected from a closely orbiting white dwarf companion. Photometric data and relevant spectral lines were also analyzed to help determine the origin of the periodic RV variations. We conclude that 627.4-day RV variations are caused by intrinsic stellar activities such as long-term pulsations or rotational modulations of surface activities based on H{\alpha} equivalent width (EW) variations of a similar period. On the other hand, 1047.1-day periodic RV variations are likely to be caused by a brown dwarf or substellar companion, which is corroborated by a recent GAIA proper motion anomaly for HD 81817. The Keplerian fit yields a minimum mass of 27.1 M_Jup, a semimajor axis of 3.3 AU, and an eccentricity of 0.17 for the stellar mass of 4.3 M_sun for HD 81817. The inferred mass puts HD 81817 b in the brown dwarf desert

Metronidazole-induced encephalopathy in a patient with liver cirrhosis

Encephalopathy is a disorder characterized by altered brain function, which can be attributed to various causes. Encephalopathy associated with metronidazole administration occurs rarely and depends on the cumulative metronidazole dose, and most patients with this condition recover rapidly after discontinuation of therapy. Because metronidazole is metabolized in the liver and can be transported by the cerebrospinal fluid and cross the blood-brain barrier, it may induce encephalopathy even at a low cumulative dose in patients with hepatic dysfunction. We experienced a patient who showed ataxic gait and dysarthric speech after receiving metronidazole for the treatment of hepatic encephalopathy that was not controlled by the administration of lactulose. The patient was diagnosed as metronidazole-induced encephalopathy, and stopping drug administration resulted in a complete recovery from encephalopathy. This case shows that caution should be exercised when administering metronidazole because even a low dose can induce encephalopathy in patients with liver cirrhosis

Comparison of tensile andcurity properties knot se of surgical sutures

The original publication is available at www.springerlink.comSutures are classified into non-absorbable and absorbable, and mechanical properties of these materials vary by the composition. Knotting induces decrease in mechanical properties. The objective of this study was to measure the tensile and knot security properties depending on the type and caliber of sutures. Changes in properties after tensile loading were measured with absorbable sutures. Tensile properties such as maximum tensile load, elongation rate, stiffness and energy absorbed before breakage of seven kinds of surgical sutures were measured. Absorbable sutures were immersed in 37 degrees C Hank`s balanced salt solution up to 14 days under the tensile load of 100 g/thread, and properties were measured again. Knot was formed with surgeon`s knot method, and tensile properties were measured. Five specimens were tested for each condition. Values were analyzed with one- or two-way analysis of variance (alpha = 0.05). Maximum tensile load of seven sutures (caliber = 4-0) ranged from 10.0 N to 14.3 N. In non-absorbable sutures, the type of suture material influenced the tensile properties (P < 0.05). In absorbable sutures, the maximum tensile load after tensile loading decreased, which was significant in chromic catgut (CC). Knot security of seven sutures (caliber = 4-0) ranged from 8.7 N to 11.9 N. Type of non-absorbable suture influenced knot security (P < 0.05), and the synthetic monofilament materials showed a tendency to be untied easily. Since no single suture material possesses all of the requirements, proper type and caliber suture should be selected based on this study.1

Effects of dimethyloxalylglycine on wound healing of palatal mucosa in a rat model

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract Background Rapid wound healing of oral soft tissue may reduce the opportunity of infection and discomfort of patients. Previous studies have demonstrated that enhancement of angiogenesis is an effective way to accelerate wound repair. In this study, to enhance angiogenesis and healing of palatal wounds, dimethyloxalylglycine (DMOG) was applied to a rat palatal wound model. DMOG is known to inhibit oxygen-dependent degradation of hypoxia inducible factor-1 alpha (HIF-1α), which can lead to up-regulation of angiogenesis markers, favoring wound repair. We also evaluated the effects of DMOG on cell migration and HIF-1α expression of rat palatal (RP) cells. Furthermore, mRNA and protein expression of vascular endothelial growth factor (VEGF) were analyzed in DMOG-treated RP cells. Methods Primary cultures of rat palatal (RP) cells were obtained from Sprague–Dawley (SD) rats. Effects of DMOG on cell viability and migration of RP cells were evaluated by using a formazan and culture insert, respectively. VEGF mRNA was observed by real-time PCR, and VEGF and HIF-1α proteins were detected by Western blotting. For the animal study, excisional wounds, 3 mm in diameter, were made at the central part of the palate of SD rats. DMOG with hyaluronic acid ointment was topically applied three times during 1 week, and then wound closures were quantitated photographically and histologically. Results DMOG was cytotoxic to RP cells at concentrations higher than 2 mM and did not affect cell migration at non-cytotoxic concentrations. mRNA and protein expression of VEGF were significantly stimulated by DMOG treatment. The protein level of HIF-1α was also stabilized in RP cells by DMOG. In the animal study, groups treated with 1 mg/ml DMOG showed an increase of rat palatal wound contractures. Conclusions DMOG enhanced wound healing of rat palatal mucosa, which was likely due to the angiogenic effect of the agent

Inhibition of odontogenic differentiation of human dental pulp cells by dental resin monomers

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Abstract Background Dental resin monomers that are leached from the resin matrix due to incomplete polymerization can affect the viability and various functions of oral tissues and cells. In this study, the effects of triethylene glycol dimethacrylate (TEGDMA) and 2-hydroxyethyl methacrylate (HEMA) on odontogenic differentiation of human dental pulp cells (HDPCs) were examined. To mimic clinical situations, dental pulp cells were treated with resin monomers for 24 h prior to the analysis of alkaline phosphatase (ALP) activity and mRNA expression of genes related to pulp cell differentiation. To elucidate the underlying signaling pathways, regulation of mitogen-activated protein (MAP) kinases by resin monomers was also investigated. Results The ALP activity of HDPCs was reduced by TEGDMA and HEMA at noncytotoxic concentrations. The mRNA expression of dentin sialophosphoprotein (DSPP), osteocalcin (OCN), and osteopontin (OPN) was also downregulated by resin monomers. However, DSPP expression was not affected by hydrogen peroxide (H2O2). Among the MAP kinases examined, ERK activation (ERK phosphorylation) was not affected by either resin monomers or H2O2, whereas JNK was phosphorylated by TEGDMA and HEMA. Phospho-p38 was upregulated by HEMA, while TEGDMA and H2O2 suppressed p38 phosphorylation. Conclusions Exposure to TEGDMA and HEMA for a limited period suppresses differentiation of HDPCs via different signaling pathways

A Type V Myosin (Myo2p) and a Rab-like G-Protein (Ypt11p) Are Required for Retention of Newly Inherited Mitochondria in Yeast Cells during Cell Division

Two actin-dependent force generators contribute to mitochondrial inheritance: Arp2/3 complex and the myosin V Myo2p (together with its Rab-like binding partner Ypt11p). We found that deletion of YPT11, reduction of the length of the Myo2p lever arm (myo2-Δ6IQ), or deletion of MYO4 (the other yeast myosin V), had no effect on mitochondrial morphology, colocalization of mitochondria with actin cables, or the velocity of bud-directed mitochondrial movement. In contrast, retention of mitochondria in the bud was compromised in YPT11 and MYO2 mutants. Retention of mitochondria in the bud tip of wild-type cells results in a 60% decrease in mitochondrial movement in buds compared with mother cells. In ypt11Δ mutants, however, the level of mitochondrial motility in buds was similar to that observed in mother cells. Moreover, the myo2-66 mutant, which carries a temperature-sensitive mutation in the Myo2p motor domain, exhibited a 55% decrease in accumulation of mitochondria in the bud tip, and an increase in accumulation of mitochondria at the retention site in the mother cell after shift to restrictive temperatures. Finally, destabilization of actin cables and the resulting delocalization of Myo2p from the bud tip had no significant effect on the accumulation of mitochondria in the bud tip

Distinct differentiation properties of human dental pulp cells on collagen, gelatin, and chitosan scaffolds

Objective. The growth and differentiation properties of human dental pulp cells (HDPC) were investigated on a variety of natural scaffolds, including 2 types of collagen, gelatin, and chitosan. Study design. Cell attachment and growth rates of HDPC on collagen (type I and type III), gelatin, and chitosan were observed. Alkaline phosphatase (ALP) activity, mRNA expression of differentiation-related genes, and mineralization of the HDPC on each scaffold were assessed. Results. Dental pulp cells attached and proliferated rapidly on collagen and gelatin, but chitosan did not properly support cell growth. The cells plated on gelatin exhibited high ALP activity, but not as high as cells plated on collagen. The expression peak of osteocalcin (OCN) mRNA from cells grown on collagen was found earlier and followed by dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP-1) mRNA expression. In cells grown on gelatin, however, OCN mRNA transcripts appeared at a later period of culture with no increase in DSPP or DMP-1 mRNA. Intensely mineralized extracellular matrix was seen in cells grown on collagen, but gelatin did not allow enough mineralization of cells in differentiation-inducing media. Conclusion. Collagen supported proliferation and differentiation of HDPC, and the expression of DSPP and DMP-1 mRNA was reduced on gelatin. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;108:e94-e100)Supported by the Korea Science and Engineering Foundation, through the National Research Laboratory Program funded by the Ministry of Science and Technology (no. M1060000283-06J0000-28310).

Quantitative analysis of the adhesion of cariogenic streptococci to orthodontic metal brackets

The aim of this study was to analyze the adhesion of cariogenic streptococci to orthodontic metal brackets in terms of the type of bacterial strains, the incubation time, and saliva coating. Two strains of Streptococcus mutans (S. mutans LM7 and S. mutans OMZ65) and two strains of S. sobrinus (S. sobrinus B13 and S. sobrinus 6715) were used. Twenty metal brackets were incubated with either unstimulated whole saliva or phosphate-buffered saline for two hours. The bacterial adhesion assays were then performed by incubating the tritium-labeled streptococci with saliva-coated or noncoated orthodontic brackets for three, six, or nine hours. The results showed a characteristic binding pattern according to the type of bacterial strains used. S. mutans OMZ65 showed the highest amount of adhesion, whereas S. sobrinus B13 showed the lowest amount of adhesion. Generally, an extended incubation time increased the adhesion of cariogenic streptococci, and the amount of adhesion was the highest after nine hours of incubation. The saliva coating did not significantly influence the adhesion of bacteria. However, this saliva-mediated adhesion differed according to incubation time. The saliva coating tended to gradually decrease the adhesion by the extended incubation time, compared with the noncoated controls. This study indicates that each strain of cariogenic streptococci has a characteristic adhesion pattern and the type of bacterial strain, the incubation time, and saliva influenced the adhesion

Machine Learning for Detecting Total Knee Arthroplasty Implant Loosening on Plain Radiographs

(1) Background: The purpose of this study was to investigate whether the loosening of total knee arthroplasty (TKA) implants could be detected accurately on plain radiographs using a deep convolution neural network (CNN). (2) Methods: We analyzed data for 100 patients who underwent revision TKA due to prosthetic loosening at a single institution from 2012 to 2020. We extracted 100 patients who underwent primary TKA without loosening through a propensity score, matching for age, gender, body mass index, operation side, and American Society of Anesthesiologists class. Transfer learning was used to prepare a detection model using a pre-trained Visual Geometry Group (VGG) 19. For transfer learning, two methods were used. First, the fully connected layer was removed, and a new fully connected layer was added to construct a new model. The convolutional layer was frozen without training, and only the fully connected layer was trained (transfer learning model 1). Second, a new model was constructed by adding a fully connected layer and varying the range of freezing for the convolutional layer (transfer learning model 2). (3) Results: The transfer learning model 1 gradually increased in accuracy and ultimately reached 87.5%. After processing through the confusion matrix, the sensitivity was 90% and the specificity was 100%. Transfer learning model 2, which was trained on the convolutional layer, gradually increased in accuracy and ultimately reached 97.5%, which represented a better improvement than for model 1. Processing through the confusion matrix affirmed that the sensitivity was 100% and the specificity was 97.5%. (4) Conclusions: The CNN algorithm, through transfer learning, shows high accuracy for detecting the loosening of TKA implants on plain radiographs

The differentiation-inducing effect of conditioned media obtained from dental pulp cells

Objective Conditioned media (CM) from human dental pulp cells (HDPC) was investigated for its effects on the proliferation and differentiation of HDPC and MG63 cells. Study design CM prepared from the primary culture of HDPC was used for the culture of HDPC and MG63. Cell growth, alkaline phosphatase (ALPase) activity, mRNA expression of differentiation-related genes, and mineralization of the HDPC and MG63 cells in the media containing CM were assessed. Results HDPC CM increased the cell growth of HDPC but decreased MG63 cell growth. ALPase activity and the mineralization of both HDPC and MG63 were enhanced by HDPC CM. The CM also up-regulated the expressions of DSPP, DMP-1, and OCN mRNA in HDPC. Pretreatment of HDPC CM with a neutralizing antibody against TGF-β completely eliminated the effect of CM on ALPase activity in HDPC. Conclusion HDPC was able to secrete odontogenic differentiation-inducing factors, in which TGF-β seems to a key element of the CM effects