Design Study of an Electron Gun for High Power Microwave Source

J. E. Han,M. Yoon,S. Y. Park 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.52

This paper describes a design study for a high-current DC thermionic electron gun. This gun is to be used for an electron generator for a high-power microwave source such as a relativistic backward wave oscillator. The designed gun showed a capability of producing an annular electron beam with very a high current of 1 kA at a 1-MeV beam energy. Obtaining such a high current beam was possible by achieving a relatively high compression ratio of about 210, which in turn was obtained by carefully optimizing the gun geometry.

N-acetylcysteine and the human serum components that inhibit bacterial invasion of gingival epithelial cells prevent experimental periodontitis in mice

Jehan Alam,백금진,최윤식,김용철,최영님 대한치주과학회 2014 Journal of Periodontal & Implant Science Vol.44 No.6

Purpose: We previously reported that human serum significantly reduces the invasion ofvarious oral bacterial species into gingival epithelial cells in vitro. The aims of the presentstudy were to characterize the serum component(s) responsible for the inhibition of bacterialinvasion of epithelial cells and to examine their effect on periodontitis induced in mice. Methods: Immortalized human gingival epithelial (HOK-16B) cells were infected with various5- (and 6-) carboxy-fluorescein diacetate succinimidyl ester-labeled oral bacteria, includingFusobacterium nucleatum, Provetella intermedia, Porphyromonas gingivalis, andTreponiema denticola, in the absence or presence of three major serum components (humanserum albumin [HSA], pooled human IgG [phIgG] and α1-antitrypsin). Bacterial adhesionand invasion were determined by flow cytometry. The levels of intracellular reactiveoxygen species (ROS) and activation of small GTPases were examined. Experimental periodontitiswas induced by oral inoculation of P. gingivalis and T. denticola in Balb/c mice. Results: HSA and phIgG, but not α1-antitrypsin, efficiently inhibited the invasion of variousoral bacterial species into HOK-16B cells. HSA but not phIgG decreased the adhesion ofF. nucleatum onto host cells and the levels of intracellular ROS in HOK-16B cells. N-acetylcysteine(NAC), a ROS scavenger, decreased both the levels of intracellular ROS and invasionof F. nucleatum into HOK-16B cells, confirming the role of ROS in bacterial invasion. Infection with F. nucleatum activated Rac1, a regulator of actin cytoskeleton dynamics. Not only HSA and NAC but also phIgG decreased the F. nucleatum-induced activation ofRac1. Furthermore, both HSA plus phIgG and NAC significantly reduced the alveolar boneloss in the experimental periodontitis induced by P. gingivalis and T. denticola in mice. Conclusions: NAC and the serum components HSA and phIgG, which inhibit bacterial invasionof oral epithelial cells in vitro, can successfully prevent experimental periodontitis.

The impact of caudally administrated tramadol on immune response and analgesic efficacy for pediatric patients: a comparative randomized clinical trial

( Jehan Ahmed Sayed ),( Sayed Kaoud Abd Elshafy ),( Emad Zareif Kamel ),( Mohamed Amir Fathy Riad ),( Amal Ahmed Mahmoud ),( Ghada Shalaby Khalaf ) 대한통증학회 2018 The Korean Journal of Pain Vol.31 No.3

Background: Immune responses appear to be affected by anesthetics and analgesics. We investigated the effects of caudal tramadol on the postoperative immune response and pain management in pediatric patients. Methods: Sixty ASA-I pediatric patients aged 3-10 years undergoing lower abdominal surgery. Patients were randomly assigned either to a caudal bupivacaine (0.25%) group (group B), or a group that received caudal tramadol (1 mg/kg) added to the bupivacaine (0.25%) (group T). Both were diluted in a 0.9% NaCl solution to a total volume of 1ml/ kg. The systemic immune response was measured by collecting blood samples preoperatively, at the end of anesthesia, and at 24 and 72 hours postoperatively, and studied for interleukin IL-6, C-reactive proteins (CRP) cortisol levels, and leucocytes with its differential count. Postoperative pain was assessed along with sedation scales. Results: Postoperative production of IL-6 was significantly higher in group B at the end of anesthesia, than at the 24th hour, and at the 72nd hour in group B and group T, respectively. The immune response showed leukocytosis with increased percentages of neutrophil and monocytes, and a decreased lymphocyte response rate within both groups with no significant differences between the groups. Cortisol and CRP were significantly higher in group B. Conclusions: Adding tramadol to a caudal bupivacaine block can attenuate the pro-inflammatory cytokine response, Cortisol, and CRP in children undergoing lower abdominal surgery. (Korean J Pain 2018; 31: 206-14)

Potential Role of Bacterial Infection in Autoimmune Diseases: A New Aspect of Molecular Mimicry

Jehan Alam,최영님,김용철 대한면역학회 2014 Immune Network Vol.14 No.1

Molecular mimicry is an attractive mechanism for triggering autoimmunity. In this review, we explore the potential role of evolutionary conserved bacterial proteins in the production of autoantibodies with focus on granulomatosis with polyangiitis (GPA) and rheumatoid arthritis (RA). Seven autoantigens characterized in GPA and RA were BLASTed against a bacterial protein database. Of the seven autoantigens, proteinase 3, type II collagen, binding immunoglobulin protein, glucose-6-phosphate isomerase, α-enolase, and heterogeneous nuclear ribonuclear protein have well- conserved bacterial orthologs. Importantly, those bacterial orthologs are also found in human-associated bacteria. The wide distribution of the highly conserved stress proteins or enzymes among the members of the normal flora and common infectious microorganisms raises a new question on how cross-reactive autoantibodies are not produced during the immune response to these bacteria in most healthy people. Understanding the mechanisms that deselect auto-reactive B cell clones during the germinal center reaction to homologous foreign antigens may provide a novel strategy to treat autoimmune diseases.

Detection of Autoantibodies against Aquaporin-1 in the Sera of Patients with Primary Sjögren’s Syndrome

Jehan Alam,최윤식,고정희,곽승기,박성환,송영욱,박경표,최영님 대한면역학회 2017 Immune Network Vol.17 No.2

The pathophysiology of glandular dysfunction in Sjögren’s syndrome (SS) has not been fully elucidated. Previously, we reported the presence of autoantibodies to AQP-5 in patients with SS, which was associated with a low resting salivary flow. The purpose of this study was to investigate the presence of anti-AQP1 autoantibodies. To detect anti-AQP1 autoantibodies, cell-based indirect immunofluorescence assay was developed using MDCK cells that overexpressed human AQP1. By screening 112 SS and 52 control sera, anti-AQP1 autoantibodies were detected in 27.7% of the SS but in none of the control sera. Interestingly, the sera that were positive for anti-AQP1 autoantibodies also contained anti-AQP5 autoantibodies in the previous study. Different from anti-AQP5 autoantibodies, the presence of anti-AQP1 autoantibodies was not associated with the salivary flow rate. Although anti-AQP1 autoantibodies are not useful as a diagnostic marker, the presence of autoantibodies to AQP1 may be an obstacle to AQP1 gene therapy for SS.

Delta Reverse Polarity Shoulder Replacement: Single Surgeon Experience with a Minimum 2-Year Follow-up

Shah Jehan,Magid Eltayeb,Mohammad Muddassir Mahmood Javaid 대한정형외과학회 2015 Clinics in Orthopedic Surgery Vol.7 No.3

Background: The delta reverse shoulder replacement system was developed for the treatment of rotator cuff arthropathy so that the deltoid can substitute for the deficient rotator cuff. To evaluate the results of delta reverse shoulder replacement for functional improvement and complications in a consecutive series by a single surgeon over a period of six years with a minimum follow-up of 2 years. Methods: The data were collected retrospectively from electronic theatre records. Over a period of 6 years (2006–2012), 46 cases that fulfilled the inclusion criteria were identified. There were 34 females and 12 males. The average age of patients was 76.2 years (range, 58 to 87 years). A single surgeon performed all procedures using the anterosuperior approach. The mean follow-up time was 49 months (range, 24 to 91 months). All cases had preoperative and postoperative Constant scores. We collected the data on indications, hospital stay, and change in the Constant score, complications, and reoperation rates. Results: The main indication for surgery was rotator cuff arthropathy (52.2%), followed by massive rotator cuff tear (28.3%), osteoarthritis (8.7%), fractures (6.5%), and rheumatoid arthritis (4.3%). Also, 65.2% of the cases were referred by general practitioners, 26% of the cases were referred by other consultants, and 8.8% of the cases were already under the care of a shoulder surgeon. The average preoperative Constant score was 23.5 (range, 8 to 59). The average Constant score at the final follow-up was 56 (range, 22 to 83). On average, there was an improvement of 33 points in the Constant score. The improvement in the Constant score was significant (p < 0.001). We observed complications in four patients (8.6%). Three of four patients (6.5%) needed reoperation. The first complication was pulmonary embolism in the early postoperative period. The other complications included dissociation of the glenosphere from the metaglene, deltoid detachment, and stitch abscess. Conclusions: This is a single-surgeon, single-approach series of 46 cases with a minimum follow-up of 2 years. At this stage, the results are encouraging with no cases of loosening, dislocation, or nerve injury.

Management of Proximal Phalangeal Fractures of the Hand Using Finger Nail Traction and a Digital Splint: A Prospective Study of 43 Cases

Shah Jehan,Th angavel Chandraprakasam,Sathya Th ambiraj 대한정형외과학회 2012 Clinics in Orthopedic Surgery Vol.4 No.2

Background: Proximal phalangeal fractures are common fractures of the hand. The fractures are diffi cult to treat because ofvicinity of two important joints and crossing long tendons. The purpose of this study was to evaluate the effi cacy of nail tractiontechnique in the management of proximal phalangeal fractures of the hand. Methods: Patients (n=43) with proximal phalangeal fractures were treated by nail traction and evaluated prospectively. We assessedall the patients at the time of presentation and then followed a standard protocol for recruiting patients. After applicationof nail traction, the patients were initially assessed at 12th day. The outcome measures included post reduction radiographicevaluation and total active motion (TAM) in fi nger at the fi nal follow-up appointment. All the patients were followed for one year. Results: The post-reduction X-ray evaluation showed good reduction in 33 cases, fair reduction in 8 and poor reduction in 2 cases. At fi nal assessment, 35 patients had good TAM score, six had fair and two had poor TAM score. Complications were noted in twopatients and these included pressure necrosis in palm and stiffness in proximal interphalangeal joint. Conclusions: The results of this prospective study show that with careful selection of patients, nail traction seems to be simple,safe and effective technique for managing proximal phalangeal fractures.

Synthesis of some pyridinethione derivatives and their biological activity

Miky, Jehane A.A.,Zahkoug, Samir A.M. The Korean Society of Pharmacognosy 1997 Natural Product Sciences Vol.3 No.2

Aminolysis, hydrazinolysis and alkylation of 4-methoxy and 4,9-dimethoxy-6-cyano-7-thione-5-methyl-7H furo [3,2-g] [1] benzopyridine (1 a-b) yielded 7N-substituted furobenzopyridine derivatives (2 a-e or the possible isomers 3 a-e and 4 a-b), (5 a,b and 6 a,b) and the ester (8 a,b). Hydrolysis of (la) with acetic acid gave the corresponding pyridone derivatives (7). Furobenzopyridinyl-7-thioacetyl hydrazide (9 a,b) have been prepared via alkylation of furobenzopyridine thione (1 a-b) with ethyl chloroacetate followed by condensation with hydrazine hydrate. Schiff base (11) was prepared by reacting (9a) with p. N,N-dimethyl aminobenzaldehyde in boiling ethanol. Treatment of (8a) with anthranilic acid gave the corresponding 7-substituted-4H-3,1-benzoxazine-4-one (10). We found that compound (11) increased bleeding, coagulating time, the total count of white blood cells, blood glucose level (cause hyperglycemia), enzymes (GOT, GPT) activities, concentration of urea and creatinine. On the other hand it decreased red blood cells number, haemoglobin content and haematocrite value.

실험계획법을 활용한 Super-TIG 용접 공정 설계

정제한(Jehan Jeong),이예경(Yegyeong Lee),박수인(Suin Park),이운재(Woonjae Lee),신상문(Sangmun Shin) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.5

Potential Role of Bacterial Infection in Autoimmune Diseases: A New Aspect of Molecular Mimicry

Alam, Jehan,Kim, Yong Chul,Choi, Youngnim The Korean Association of Immunobiologists 2014 Immune Network Vol.14 No.1

Molecular mimicry is an attractive mechanism for triggering autoimmunity. In this review, we explore the potential role of evolutionary conserved bacterial proteins in the production of autoantibodies with focus on granulomatosis with polyangiitis (GPA) and rheumatoid arthritis (RA). Seven autoantigens characterized in GPA and RA were BLASTed against a bacterial protein database. Of the seven autoantigens, proteinase 3, type II collagen, binding immunoglobulin protein, glucose-6-phosphate isomerase, ${\alpha}$-enolase, and heterogeneous nuclear ribonuclear protein have well-conserved bacterial orthologs. Importantly, those bacterial orthologs are also found in human-associated bacteria. The wide distribution of the highly conserved stress proteins or enzymes among the members of the normal flora and common infectious microorganisms raises a new question on how cross-reactive autoantibodies are not produced during the immune response to these bacteria in most healthy people. Understanding the mechanisms that deselect auto-reactive B cell clones during the germinal center reaction to homologous foreign antigens may provide a novel strategy to treat autoimmune diseases.