On the Use of Cob(II)alamin as a Spin Trap in Radical Polymerization

Yeap-Hung Ng,Fabio di Lena,Christina L. L. Chai 한국고분자학회 2012 Macromolecular Research Vol.20 No.5

Hydroxocobalamin reduced with ascorbic acid acts as a spin trap for free radical polymerization in water. The reaction mechanism is dependent on monomer type. An acrylic olefin such as 2-hydroxyethyl acrylate (HEA)is polymerized at pH 7 and in the presence of a conventional radical source mainly through reversible deactivation by a coupling mechanism. In contrast, a methacrylate like polyethylene glycol methacrylate undergoes catalytic chain transfer oligomerization.

Atom Transfer Radical Polymerization (ATRP) of Methyl Methacrylate Mediated by Iron(II) Chloride in the Presence of Polyethers as Both Solvents and Ligands

Yeap-Hung Ng,Fabio di Lena,Christina L. L. Chai 한국고분자학회 2012 Macromolecular Research Vol.20 No.6

Iron(II) chloride in combination with various polyethers form the homogeneous, “green” catalytic mixtures that are capable of promoting the well-controlled atom transfer radical polymerization of methyl methacrylate in the absence of any additional ligands or solvents. With poly(ethylene glycol)s, linear semilogarithmic plots of conversion vs. time and of molecular weight vs. monomer conversion were obtained with polydispersities as low as 1.32. The effects of the polyether structure, molecular weight, and chain-end functionality on the polymerization kinetics were also investigated.

Deformation of Median Nerve during Active and Passive Wrist Holding at Proximal Carpal Tunnel

( Ping Yeap Loh ),( Satoshi Muraki ) 한국감성과학회 2014 춘계학술대회 Vol.2014 No.-

The first objective of this study was to identify the deformation of the median nerve cross-sectional area (MNCSA) at different wrist active and passive holding positions. The second objective was to compare the wrist circumference, wrist width, and wrist depth between dominant and non-dominant hands. A total of eight right-handed healthy male adults (age 27.0 ±3.5 years) participated in this study. Ultrasound examination was performed at the proximal carpal tunnel to examine the median nerve on the transverse plane. A total of three wrist positions were examined, namely, wrist neutral, wrist flexion 30°, and wrist extension 30°, in active and passive holding positions for both dominant and non-dominant hands. Paired t-test showed significant differences between dominant (D) and non-dominant (ND) hands in wrist circumference, wrist width, and wrist depth (D = 39.6 ± 2.8 mm, ND = 38.3 ± 2.7 mm, p<0.01). The differences of MNCSA between dominant and non-dominant hands were significant (p<0.001) at both active (D = 7.93 ± 0.63 mm2, ND = 6.98 ± 0.42 mm2) and passive holding positions (D = 8.22 ± 0.72 mm2, ND = 7.06 ± 0.44 mm2). Two-way repeated-measures ANOVA showed that wrist flexion 30° and wrist extension 30°caused significant reductions in MNCSA when compared with wrist neutral (p<0.001) in both active and passive holding positions.

Deformation of Median Nerve during Active and Passive Wrist Holding at Proximal Carpal Tunnel

Ping Yeap LOH,Satoshi MURAKI 대한인간공학회 2014 대한인간공학회 학술대회논문집 Vol.2014 No.5

The first objective of this study was to identify the deformation of the median nerve cross-sectional area (MNCSA) at different wrist active and passive holding positions. The second objective was to compare the wrist circumference, wrist width, and wrist depth between dominant and non-dominant hands. A total of eight right-handed healthy male adults (age 27.0 ± 3.5 years) participated in this study. Ultrasound examination was performed at the proximal carpal tunnel to examine the median nerve on the transverse plane. A total of three wrist positions were examined, namely, wrist neutral, wrist flexion 30°, and wrist extension 30°, in active and passive holding positions for both dominant and non-dominant hands. Paired t-test showed significant differences between dominant (D) and non-dominant (ND) hands in wrist circumference (D = 15.9 ± 0.6 cm, ND = 15.7 ± 0.6 cm, p<0.05), wrist width (D = 56.3 ± 3.6 mm, ND = 54.0 ± 2.1 mm, p<0.05), and wrist depth (D = 39.6 ± 2.8 mm, ND = 38.3 ± 2.7 mm, p<0.01). The differences of MNCSA between dominant and non-dominant hands were significant (p<0.001) at both active (D = 7.93 ± 0.63 mm<SUP>2</SUP>, ND = 6.98 ± 0.42 mm<SUP>2</SUP>) and passive holding positions (D = 8.22 ± 0.72 mm<SUP>2</SUP>, ND = 7.06 ± 0.44 mm<SUP>2</SUP>). Two-way repeated-measures ANOVA showed that wrist flexion 30° and wrist extension 30° caused significant reductions in MNCSA when compared with wrist neutral (p<0.001) in both active and passive holding positions. However, wrist active and passive holding did not have a significant effect on MNCSA changes. In conclusion, our findings showed that significant reduction of MNCSA was associated with wrist flexion-extension motion and there was significant bilateral asymmetry in physical characteristics of the wrist.

Endoscopic Removal of a Fecalith or Fecomucolith in a Rectal Stump or Pouch

Evie Yeap,Ratheesraj Ratinam,Asiri Arachchi,James Lim,Yeng Kwang Tay,Zeev Duieb 대한대장항문학회 2021 Annals of Coloproctolgy Vol.37 No.5

Fecaliths or fecomucoliths can form in rectal stumps after a Hartmann procedure or in a coloneovaginal conduit. They can cause significant distress to the patient by causing symptoms such as discharge and odor. We describe a novel and effective method of endoscopic obliteration and removal where other techniques such as removal during examination under anesthesia or serial enemas have failed. By using a combination of hydrodissection with a saline injector gun and biopsy forceps and a polypectomy snare to break down the fecomucolith or fecalith, this troublesome problem can be resolved endoscopically. Successful removal of the fecalith/fecomucolith and resolution of the symptoms for the patients were achieved. No complications are reported. We describe an effective and novel method for endoscopic removal of fecaliths and fecomucoliths.

A Literature Review of Infection with ESKAPE Pathogens in Oral and Maxillofacial Region

Park, Sang-Yeap,You, Jae-Seek,Moon, Seong-Yong,Oh, Ji-Su,Choi, Hae-In,Jung, Gyeo-Woon Korean Academy of Orofacial Pain and Oral Medicine 2021 Journal of Oral Medicine and Pain Vol.46 No.3

Odontogenic infection in the oral and maxillofacial regions caused by bacteria (mostly of oral origin) is one of the most common diseases encountered by dentists. Localized infection can easily be treated with incision and drainage followed by antibiotics. Emergence of multidrug resistant (MDR) bacteria called "Superbacteria" has become one of the serious problems in modern society, due to its small window of opportunity for treatment and high casualty. The acronym "ESKAPE", encompassing the common and serious MDR pathogens stand for Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. Literature search was performed in Medline, PubMed and Google Scholar ranging from 2012 to 2020. ESKAPE patient's infection period was longer than that of non-ESKAPE group, and the treatment method due to antibiotic resistance was also complicated. The purpose of this study is to investigate infection caused by ESKAPE pathogens in the oral and maxillofacial regions through literature review and to inform dental surgeons of the danger of ESKAPE pathogens and to suggest viable treatment options. Many studies worldwide reported infections associated with ESKAPE pathogens, but only limited number of studies targeted infection in oral and maxillofacial regions. Further research is required with more data on ESKAPE bacteria and their infection, especially in oral and maxillofacial regions.

The Asian Federation of Osteoporosis Societies' call to action to improve the undertreatment of osteoporosis in Asia

Swan Sim Yeap,Unnop Jaisamrarn,박예수,Yasuhiro Takeuchi,Weibo Xia 대한골다공증학회 2017 Osteoporosis and Sarcopenia Vol.3 No.4

.

Natural Resource Beta Wave Technology To Stimulate Rural Primary Education

Teik Wei YEAP,Salleh ABD RASHID 한국직업자격학회 2017 한국직업자격학회 학술대회 Vol.2017 No.10

The purpose of this study is to evaluate the effectiveness of using Natural Resource Beta Wave Technology (NRBWT) in literacy to stimulate students with learning disabilities in chinese primary school in Perlis, the Rural Northen State in Malaysia. This quantitative research was designed using Quasi-experimental method. 31 respondents selected as a sample in Sekolah Jenis Kebangsaan Cina (SJKC) in Perlis, Malaysia. This study was treated with Simulation Beta Wave with 20Hz for a period of 9 weeks and without any controlled sample treatment group. A cognitive test of C1 and C2 where ‘C’ stands for ‘construct’ tool was used to collect data before and after the intervention was done. Amidst the treatment, the pre-test and post-test achievement tests were conducted to evaluate the effectiveness of the Beta Wave of 20Hz. The findings of this study was analyzed using the SPSS 22 with descriptive mean, frequency, % and multiple regression. The results indicates that the effect of Beta wave green technology with 20Hz gives significant positive influence in the learning of students with learning disabilities as a Northen Rural State in Malaysia.

Analysis of Non-Universality of Golden Ratio Known as a Perfect Figurative Ratio

Hong, Sung Yeap(홍성엽),Lee, Cheol Ho(이철호) 한국전시산업융합연구원 2015 한국과학예술융합학회 Vol.22 No.-

Golden ratio, defined as symbol φ (Phi) simply in the 20th century, was acknowledged as the most balanced beautiful ratio, so it has been used in architecture or pictures etc. Golden ratio is the significant figurative ratio deeply related to our actual lives but it is not explained why many people consider it cozy and stable even in today, technologically advanced. Some refutation that golden ratio is only mathematical theory but there are few cases to be applied to practice. First, it was examined that there are many cases to exaggerate a small number of coincidences with golden ratio by chance in spite of numerous ratios in the nature. Besides, there are many cases that proportions of rectangular objects such as name card, credit card or proportions such as HDTV and wide monitors etc are approximate values of golden ratio but it is hard to place under the category of golden ratio for there are big differences with golden ratio. Rather, it was confirmed that it is close to Geumgang ratio, Korean own figurative ratio. Geumgang ratio is also called harmonic proportion and has flexibility to fit well to the cultural atmosphere of modern society which respects diversity. In this point of view, it is considered the active promotion according to global age would be need on the basis of more in-depth study on Geumgang ratio, likewise examples of golden ratio in the Western world.

A Study on the Application of Nano-material Focused on CNT and Graphene as Textile Fire Retardant

Hong, Sung Yeap(홍성엽) 한국전시산업융합연구원 2017 한국과학예술융합학회 Vol.31 No.-

One of the main reason of the disastrous fire is polymer which is used in livelihood. Because polymers are organic materials combined carbon, hydrogen and oxygen, polymers are vulnerable to heat. To decrease the disastrous polymers are necessary flame retardant which are additives not to burn by improving the inflammability of a polymer. The research method is as follows. Firstly, introduction of the fire retardant which are used in textile is variously used as not only household clothing but also all sorts of livelihood items. Development of fire retardant facilitates not only reinforcing fire retarding but also producing fabric with various functions such as sterilization, deodorization, and water repellent, so makes the use in the present restricted fields spread to new uses. Production of this multifunctional fabric facilitates combining existing fabric field with the field of engineering related to disaster prevention. Secondly, presentation of Kinds of fire retardants which are divided into addition fire retardant and responsive fire retardant. Addition fire retardant is a method mixing it simply by putting it as additive during compounding process, and responsive fire retardant gives fire retarding by producing a fire retarding polymer by introducing a monomer giving fire retarding to main chain of a polymer, or by combining fire retarding substance chemically in the end or side chain of a polymer by introducing reactive groups into a polymer. Thirdly, the introduction of nanocomposite fire retardants such as CNT or graphene fire retardants emerging from a limit of existing fire retardants reduces true character of fabric. Carbon nanotube CNT) is an allotrope of carbon with cylindroid nanostructure. Graphene is also one of carbon allotropes and has a structure that carbon atoms gather become 2D plane. Finally, CNT and graphene are overviewed as the promising materials for the flame retardant. The various results of CNT and graphene as nanofiller to retard the fire are mentioned. By the understanding of the retardation properties of those material, textile industry in the areas of clothing and household items will be more easily convergence with the nanotechnology.