Nanoscale Pillar-Enhanced Tribological Surfaces as Antifouling Membranes

Choi, Wansuk,Chan, Edwin P.,Park, Jong-Hyun,Ahn, Won-Gi,Jung, Hyun Wook,Hong, Seungkwan,Lee, Jong Suk,Han, Ji-Young,Park, Sangpil,Ko, Doo-Hyun,Lee, Jung-Hyun American Chemical Society 2016 ACS APPLIED MATERIALS & INTERFACES Vol.8 No.45

<P>We present a nonconventional membrane surface modification approach that utilizes surface topography to manipulate the tribology of foulant accumulation on water desalination membranes via imprinting of submicron titanium dioxide (TiO2) pillar patterns onto the molecularly structured, flat membrane surface. This versatile approach overcomes the constraint of the conventional approach relying on interfacial polymerization that inevitably leads to the formation of ill-defined surface topography. Compared to the nonpatterned membranes, the patterned membranes showed significantly improved fouling resistance for both organic protein and bacterial foulants. The use of hydrophilic TiO2 as a pattern material increases the membrane hydrophilicity, imparting improved chemical antifouling resistance to the membrane. Fouling behavior was also interpreted in terms of the topographical effect depending on the relative size of foulants to the pattern dimension. In addition, computational fluid dynamics simulation suggests that the enhanced antifouling of the patterned membrane is attributed to the enhancement in overall and local shear stress at the fluid TiO2 pattern interface.</P>

Effects of Lumbar Mobilization for Lower Limb Strength in Healthy Individuals: A Protocol for Systematic Review and Meta-Analysis

Wansuk Choi,Taeseok Choi,Hojung An,Jisung Kim,Seoyoon Heo 국제물리치료연구학회 2020 Journal of International Academy of Physical Ther Vol.11 No.2

Background: The effect of mobilization on lumbar back pain has been fully described in several clinical aspects, but evidence for muscle strength would be still less clear. Objective: To assess the effect of lumbar mobilization on lower limb strength in healthy individuals. Methods and Analysis: Healthy people aged 18-65 will be included regardless of race or sex. Original peer-reviewed primary reporting randomized controlled trials (RCTs) will be included. Electronic databases, such as MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Web of Science, Pedro, CINAHL, ClinicalTrials.gov will be searched from inception until July 30. Only studies published in English will be included in this review. Two reviewers will complete the screening for eligibility independently, and the other two reviewers will also complete the risks of data extraction and bias assessment independently. Lower Limb strength will be assessed as primary outcome, and particular intervention or participant characteristics will be assessed as the secondary outcomes. Meta-analysis will be conducted using Review Manager 5.3.3, and evidence level will be assessed using the method for Grading of Recommendations Assessment, Development and Evaluation. Outcomes will be presented as the weighted mean difference or standardized mean difference with 95% CI. If I2 ≤ 50%, P>.1, the fixed effect model will be used, otherwise, random-effects model will be used. Ethics and dissemination: This review might not be necessary ethical approval because it does not require individual patient’s data; these findings will be published in conference presentations or peer-reviewed journal articles. PROSPERO registration number: CRD42020150144.

Short-term Benefits of Mobilization for Patients with Non-Specific Neck Pains: Executive Function and Neck Pain Intensity

Choi, Wansuk,Heo, Seoyoon International Academy of Physical Therapy Research 2019 Journal of International Academy of Physical Ther Vol.10 No.2

Background: Cervical mobilization has been applied mainly for the improvement of arm and neck movements and pain reduction, and little research has been done to improve the executive function. Since this kind of so-called mechanical neck pain is one of most common symptoms, there are controversial issues about this with spine alignment. Posteroanterior (PA) mobilization from the Maitland concept is a process of examination, assessment, and treatment of neuromusculoskeletal disorder by manipulative physical therapy. Objective: To examine the short-term benefits of mobilization for patients with non-specific neck pain. Design: Dual-group Pretest-Posttest Design from the Quasi-Experimental research Methods: Fourteen participants (male 8, female 6; 20's of their age) with non-specific neck pains which are distributed all the unilateral or bilateral body side were recruited. Participants were categorized to Neck Pain with Movement Coordination Impairments (NPMCI) and Neck Pain with Mobility Deficits (NPMD) groups according to the results of physical examination. Professional physical therapist who has over 15-years-of clinical experience applicated manipulative therapy for the neck pain, an occupational therapist only conducted evaluations; K-NDI (Korean version of the Neck Disability Index), VAS (Visual Analog Scale), BDS-K (Korean version of Behavioral Dyscontrol Scale) for decreasing possible adverse effects; there were no person who reported other symptoms followed 4 weeks from the trial. Results: In the NPMCI group, data analysis indicated statistical differences between the PA mobilization interventions in NDI and BDS-K; even though, pain was reduced in VAS, this is not a significantly differ. In the NPMD group, data analysis represented statistical differences between the PA mobilization interventions in NDI, VAS and BDS-K; the scores were represented to be increased or the pain got relief. Conclusions: PA mobilization techniques according to Maitland concept have beneficial effects in patients with neck pain and other clinical positive effects which included neck disability, pain itself and motor function of upper extremity.

Sharkskin-mimetic desalination membranes with ultralow biofouling

Choi, Wansuk,Lee, Changhoon,Lee, Dahye,Won, Young June,Lee, Gi Wook,Shin, Min Gyu,Chun, Byoungjin,Kim, Taek-Seung,Park, Hee-Deung,Jung, Hyun Wook,Lee, Jong Suk,Lee, Jung-Hyun The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.45

<P>Biofouling is a pervasive problem for any materials that are exposed to aquatic environments. Especially, it is a dire problem for the desalination membranes used to sustainably supply clean water, necessitating development of the methods to mitigate membrane biofouling. We present a topological modification approach to achieve ultralow fouling of water desalination membranes by realizing the sharkskin-mimetic (Sharklet) surface patterns and identify their unique antifouling mechanism based on computational fluid dynamics simulation. Our approach relies on a newly developed layered interfacial polymerization that can produce a conformal selective layer on patterned porous supports prepared by phase separation micromolding. The Sharklet-patterned membrane exhibited remarkably low biofouling compared to the conventional membranes with irregular roughness and topologically modulated membranes with simple patterns. Its superior biofouling resistance is attributed to the unique Sharklet geometry that can significantly inhibit biofilm growth. Furthermore, under dynamic flow conditions, the intricate Sharklet geometry induces a complex surface flow by symmetrically generating a secondary flow perpendicular to the primary flow, forming a periodic inflow and outflow along the pattern. The reinforced primary and secondary flows of the Sharklet pattern may further contribute to its excellent biofouling resistance.</P>

Short-term Benefits of Mobilization for Patients with Non- Specific Neck Pains: Executive Function and Neck Pain Intensity

Wansuk Choi,Seoyoon Heo 국제물리치료연구학회 2019 Journal of International Academy of Physical Ther Vol.10 No.2

Background: Cervical mobilization has been applied mainly for the improvement of arm and neck movements and pain reduction, and little research has been done to improve the executive function. Since this kind of so-called mechanical neck pain is one of most common symptoms, there are controversial issues about this with spine alignment. Posteroanterior (PA) mobilization from the Maitland concept is a process of examination, assessment, and treatment of neuromusculoskeletal disorder by manipulative physical therapy. Objective: To examine the short-term benefits of mobilization for patients with non-specific neck pain. Design: Dual-group Pretest-Posttest Design from the Quasi-Experimental research Methods: Fourteen participants (male 8, female 6; 20’s of their age) with nonspecific neck pains which are distributed all the unilateral or bilateral body side were recruited. Participants were categorized to Neck Pain with Movement Coordination Impairments (NPMCI) and Neck Pain with Mobility Deficits (NPMD) groups according to the results of physical examination. Professional physical therapist who has over 15-years-of clinical experience applicated manipulative therapy for the neck pain, an occupational therapist only conducted evaluations; K-NDI (Korean version of the Neck Disability Index), VAS (Visual Analog Scale), BDS-K (Korean version of Behavioral Dyscontrol Scale) for decreasing possible adverse effects; there were no person who reported other symptoms followed 4 weeks from the trial. Results: In the NPMCI group, data analysis indicated statistical differences between the PA mobilization interventions in NDI and BDS-K; even though, pain was reduced in VAS, this is not a significantly differ. In the NPMD group, data analysis represented statistical differences between the PA mobilization interventions in NDI, VAS and BDS-K; the scores were represented to be increased or the pain got relief. Conclusions: PA mobilization techniques according to Maitland concept have beneficial effects in patients with neck pain and other clinical positive effects which included neck disability, pain itself and motor function of upper extremity.

Layer-by-Layer Assembly of Graphene Oxide Nanosheets on Polyamide Membranes for Durable Reverse-Osmosis Applications

Choi, Wansuk,Choi, Jungkyu,Bang, Joona,Lee, Jung-Hyun American Chemical Society 2013 ACS APPLIED MATERIALS & INTERFACES Vol.5 No.23

칼텐본-에비엔즈컨셉의 어깨관절 아래쪽미끄러뜨림 적용시 관절의 이동성 연구

( Wansuk Choi ),( Juhyun Park ),( Bongjae Jung ),( Okkon Moon ),( Kyungok Min ),( Hojung An ) 한국방사선학회 2012 한국방사선학회 논문지 Vol.6 No.5

본 연구는 오른쪽 어깨관절에 칼텐본-에비엔즈컨셉 미끄러뜨림 등급Ⅱ와 Ⅲ으로 아래쪽미끄러뜨림 적용시 위팔뼈 머리의 이동거리 및 벌림각도(abduction angle)의 변화를 알아보고자 하였다. 미끄러뜨림 등급Ⅱ(Grade Ⅱ) 적용시 위팔뼈머리는 초기보다 아래쪽으로 5㎜ 가량 이동하였고 등급Ⅲ 적용시 8㎜ 가량 이동하였다. 이동거리에 대한 성별 비교에서는 남자가 여자에 비해 등급별로 이동거리가 높게 나타났으나 통계적으로 유의한 차이는 나타나지 않았다. 등급 Ⅱ(Grade Ⅱ) 적용시 벌림각도는 초기보다 10°가량, 등급Ⅲ(Grade Ⅲ) 적용시 12°가량 증가하였다. 벌림각도에 대한 성별 비교에서는 모든 등급별로 여자가 남자보다 벌림각도가 크게 나타났으나 통계적으로 유의한 차이는 나타나지 않았다. 본 연구를 통해 미끄러뜨림 등급 적용시 위팔뼈머리의 운동형상학적 변화를 알아보았으며 향후 추가 연구를 통해 이들 변화가 주변 구조물에 미치는 영향에 대해 알아본다면 보다 과학적인 근거중심의 치료를 기대할 수 있을 것으로 사료된다. This study aimed at identifying changes in the acromiohumeral distance (AHD) and abduction angle of the arm when the caudal gliding gradeⅡ and Ⅲ of Kaltenborn-Evjenth ConceptⓇ are applied to the right glenohumeral joint. The humeral head moved down about 5㎜ from the initial position when the gliding gradeⅡ was applied, and about 8㎜ from the initial position when the gliding gradeⅢ was applied. Although men showed a higher acromiohumeral distance per grade than women in comparisons by gender for the acromiohumeral distance, there was no significant difference in statistics. The Abduction angle improved about 10° from the initial angle when the gliding gradeⅡ was applied, and about 12° from the initial angle when the gliding gradeⅢ was applied. Although women showed the abduction angle greater than men for every grade in comparisons by gender for the abduction angle, there was no significant difference in statistics. Based on the aforesaid findings, the extent of kinematic changes in the humeral head could be identified when the gliding grades were applied. Accordingly, it is considered that more scientific evidence based treatments could be expected if influences on the surrounding structures by these changes could be learned through more studies in the future.

Thin film composite reverse osmosis membranes prepared via layered interfacial polymerization

Choi, Wansuk,Jeon, Sungkwon,Kwon, Soon Jin,Park, Hosik,Park, You-In,Nam, Seung-Eun,Lee, Pyung Soo,Lee, Jong Suk,Choi, Jongmoon,Hong, Seungkwan,Chan, Edwin P.,Lee, Jung-Hyun Elsevier 2017 Journal of membrane science Vol.527 No.-

<P><B>Abstract</B></P> <P>Reverse osmosis (RO) process using a thin-film composite (TFC) membrane is a current leading technology for water desalination. The polyamide permselective layer of the TFC membrane enables salt retention and water permeation, with the ultimate goal of minimizing the permselective layer thickness for maximum energy efficiency. Yet this drive towards reducing the permselective layer thickness is greatly handicapped by the interfacial polymerization (IP) approach used to fabricate TFC membranes. We present layered interfacial polymerization (LIP) as a new paradigm for fabricating TFC membranes with unprecedented nanoscale control in the permselective layer thickness and smoothness, coupled with the advantage of industrial scale manufacturability. Membranes fabricated using LIP demonstrated high NaCl rejection necessary for water desalination, with water permeance ≈ 86% and permselectivity ≈ 450% greater than that of the membranes prepared using conventional IP and comparable water permeance and permselectivity ≈ 17% higher than that of commercial RO membranes. In addition, the unique smooth morphology of the LIP-assembled membrane surface enabled to mitigate the membrane fouling compared to the characteristic rough surface of the conventional IP-assembled membrane.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PA TFC RO membrane is fabricated via layered interfacial polymerization (LIP). </LI> <LI> LIP enables nanoscale and independent property control with process simplicity. </LI> <LI> LIP membrane has permselectivity greater than both commercial and control membranes. </LI> <LI> LIP membrane exhibits lower fouling property than the conventional control membrane. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Deep Learning Frameworks for Cervical Mobilization Based on Website Images

Choi, Wansuk,Heo, Seoyoon International Academy of Physical Therapy Research 2021 Journal of International Academy of Physical Ther Vol.12 No.1

Background: Deep learning related research works on website medical images have been actively conducted in the field of health care, however, articles related to the musculoskeletal system have been introduced insufficiently, deep learning-based studies on classifying orthopedic manual therapy images would also just be entered. Objectives: To create a deep learning model that categorizes cervical mobilization images and establish a web application to find out its clinical utility. Design: Research and development. Methods: Three types of cervical mobilization images (central posteroanterior (CPA) mobilization, unilateral posteroanterior (UPA) mobilization, and anteroposterior (AP) mobilization) were obtained using functions of 'Download All Images' and a web crawler. Unnecessary images were filtered from 'Auslogics Duplicate File Finder' to obtain the final 144 data (CPA=62, UPA=46, AP=36). Training classified into 3 classes was conducted in Teachable Machine. The next procedures, the trained model source was uploaded to the web application cloud integrated development environment (https://ide.goorm.io/) and the frame was built. The trained model was tested in three environments: Teachable Machine File Upload (TMFU), Teachable Machine Webcam (TMW), and Web Service webcam (WSW). Results: In three environments (TMFU, TMW, WSW), the accuracy of CPA mobilization images was 81-96%. The accuracy of the UPA mobilization image was 43~94%, and the accuracy deviation was greater than that of CPA. The accuracy of the AP mobilization image was 65-75%, and the deviation was not large compared to the other groups. In the three environments, the average accuracy of CPA was 92%, and the accuracy of UPA and AP was similar up to 70%. Conclusion: This study suggests that training of images of orthopedic manual therapy using machine learning open software is possible, and that web applications made using this training model can be used clinically.

Laboratory Experiments for the Force and Load with Pseudo-Dynamic Test: Ex-vivo Study for the Manual Therapy

Wansuk Choi,Taeseok Choi,Seoyoon Heo,Wooram Lee 국제물리치료연구학회 2019 Journal of International Academy of Physical Ther Vol.10 No.4

Background: Because of the lack of accurate values for applied forces in manual therapy, manual therapists relies on the magnitude of the individual’s perception during applying the force. However, excessive loading maneuvers carry risks for patients. Objective: To establish the relationship between the maximal force applied to swine skin with the specific region, sex, and baseline parameters of the subject. Design: Ex-vivo Study and laboratory Experimental research Methods: 3.5 kg of Korean pork sirloin that is a piece of swine was handled and it was set 3 dimensions; #A; #B; #C. Forty-seven participants who has no experience in physical therapy randomly carried out the experiment, indicated to push each place of the pressure spots with same posture and process under supervision from the instructor who has over 15 years of manual therapy, and we measured the pressure force in each time. Results: The biggest pressure force was recorded in spot #A, and #B was represented after #C. Pressure on #A showed certain statistic relation with height (r=.317, p<.05) and weight (r=.434, p<.01); pressure on #B showed certain relation which has statistical meaning with only height (r=.401, p<.01); pressure on #C emerged to have statistic relationship with height (r=.308, p< .05)and weight (r=.428, p<.01). The age aspect revealed relation with pressure on #A, #B and #C, but that was not statistically significant. Conclusions: It can be inferred that there is the most loss of pressure in the area where cartilage is like an island in the middle.