• Radiation Oncology Journal
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• 제14권1호
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• pp.25-31
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• 1996

목적 : 절제가능한 직장암에서 보조요법으로써 sandwich technique 방사선치료를 시행한후 이들의 결과를 다양한 변수에 따라 수술후방사선치료와 비교 분석하여 봄으로써 sandwich technique 방사선치료의 상대적인 장점을 알아보고자 하였다. 대상 및 방법 : 1989년 1월부터 1994년 5월까지 인제대학교부속 백병원에서 직장암으로 진단받은 환자로서 sandwich technique(수술전과 수술후의 방사선치료)의 방사선치료를 받은 20명 명과 근치적 절제술후 수술후방사선치료를 받은 31명을 대상으로 임상분석을 시행하였다. 방사선 치료는 4MV Linear Accelerator를 이용하여 원발병소 및 국소임파절을 포함하는 부위에 4조사야로 치료하였다. Sandwich technique 방사선치료는 국소적으로 진전된 병기로 진단된 경우 수술전에 매일 300cGy/fx씩 총 1500cGy를 조사하고 즉시 수술을 시행하였다. 이들중 수술후 병리조직검사소견상 Modified Astler-Coller변기 B2, B3, C로 진단된 경우 수술후방사선치료를 매일 180cGy/fx씩 총 2500-4500cGy 조사하였다. 수술후방사선치료를 받은 군은 병기 B2, B3, C의 환자들로서 수술후 약 4-6주경에 매일 180cGy/fx씩 총 4500-6120 cGy를 조사하였다. 보조 항암요법은 5-FU +Mitomycin+Leucovorin, 5-FU+Leucovorin, 경구용 5-FU단독요법으로 1-12회가 시행되었는데 sandwich technique군에서 15/20명($75\%$), 수술후방사선치료군에서 26/31명($84\%$)이 시행되었다. 총 추적관찰기간은 10-73개월로 중앙값은 25개월이었다. 결과 : Sandwich technique군과 수술후방사선치료군에서 시행된 수술방법을 살펴보면 복부회음절제술이 각각 $30\%$(6/20)과 $68\%$(2/31), 전방절제술이 각각 $70\%$(14/20)과 $32\%$(10/31)에서 시행되었다. 5년 생존율은 sandwich technique군과 수술후방사선치료군에서 각각 $60\%$와 $71\%$(p>0.05)였고 5년 무병생존율은 두군 모두 $63\%$로 동일하였다. 치료실패양상을 보면 sandwich technique군은 국소실패율 $11\%$(2/20), 원격전이율 $11\%$(2/20)였고 수술후방사선치료군은 국소실패을 $7\%$(2/31), 원격전이율 $20\%$(6/31)였다. 수술후 합병증은 sandwich technique군에서만 3예가 발생하였는데 수술후 2일째 패혈증 및 수술접합부위의 누수 1예, 수술상처의 누루 1예, 수술 부위의 누수 1예였다. 방사선치료의 급성 부작용은 RTOG/EORTC등급 I-II의 위장관 합병증이 양쪽 군에서 $52\%$와 $55\%$로 유사하였고 요도계의 합병증은 sandwich technique으로 치료한 환자에서만 $15\%$(3/20)관찰되었다. 만성 합병증은 소장관 폐쇄로 수술이 필요했던 경우가 양쪽 군에서 각각 2명씩이었고 sandwich technique군에서 출혈성 방광염 1예, 항문협착 1예가 발생하였다. 예후인자들(연령, 성별, 종양의 위치, 절제술의 종류, 병기, 약물치료 유무)중 복부회 음절제술이 생존율 향상과 관련되었고(p<0.05) 병기 B, C에서 5년 무병생존율이 각각 $90\%$, $50\%$로 통계적인 의미는 없었으나 차이를 보여주었다. 결론 : 절제 가능한 직장암에서 sandwich technique 방사선치료가 다른 형태의 방사선치료와 유사한 국소실패율과 원격전이율을 보여주면서 통계적으로 의미는 없었지만 원격전이율의 감소를 관찰할 수 있었다($11\%$ versus $20\%$). 또한 심각한 합병증 발생빈도도 증가하지 않았다. 따라서 향후 더 많은 환자를 대상으로 오랜 기간의 추적관찰을 시행한다면 원격전이율 및 생존율에 미치는 sandwich technique 치료의 의미있는 결과를 얻을 수 있으리라 생각한다.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.447-462
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• 1993

To evaluate the marginal leakage in Class V cavity this study has been undertaken to compare the sandwich technique with the conventional method, and find out the effect of lining material, lining method, and polishing time on sandwich technique. Ninty extracted teeth were divided into eight test groups and a control group, and were prepared with a buccal Class V cavity. Four test groups were lined with Dentin Cement whereas the other four test groups were lined with Vitrabond. Half of the either group were lined 0.5mm short of the carvosurface margin and the rest were lined completely to the carvosurface margin. The four subgroups were further divided into specimens which were polished immediately and 24 hours after resin filling. The polished specimens were immersed in $37^{\circ}C$, 0.5% methylene blue solution for 24 hous after thermocycling at $5^{\circ}C$ and $55^{\circ}C$, 200 times and buccolingually sectioned. The sectioned specimens were examined dye penetration under the light microscope. The following results were obtained, 1. At the enamel margin, the conventional method showed a lower microleakage than the sandwich technique. The difference between the control and Vitrabond group was statistically significant(P<0.05), but no difference between the control and Dentin Cement group, and between the lining materials was observed. 2. At the dentinal margin, the sandwich technique showed a significant lower amount of microleakage (P<0.05), but there was no significant difference between the lining materials. 3. Regardless of the lining material, lining method, and polishing time used, values of microleakage were significantly higher at the dentinal margin compared to the enamel margin(P<0.05). 4. In specimens till the cavosurface margin, microleakage at the dentinal margin was less with the light-cured base than with the chemically-cured base, but there was no siginificantly difference between the lining materials regarding the lining method and polishing time. 5. The lining material, lining method, and polishing time did not affect the amount of micro leakage in the sandwich technique(P<0.05).

• 항공우주시스템공학회지
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• 제7권1호
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• pp.39-43
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• 2013

In this study, damage assesment and repair technique of aircraft adopted on Sandwich composite structure were performed. The sandwich composite structure were damaged by drop weight type impact test machine. The damaged sandwich composite structure was repaired using external patch repair method after removing damaged area. This study presents comparison results of the experimental investigation between the impact damaged and the repaired specimen.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권3호
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• pp.276-282
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• 2008

Objective: This is to report the efficacy of the sandwich technique for bone augmentation in a moderate atrophic posterior mandible through clinical and histological results in two cases. Subjects and Method: Two patients selected had moderate bone resorption in left lower edentulous area. Sandwich osteotomy using the piezosurgery was performed and the osteomized alveolar segments were elevated by 6mm in each two patients. The interpositional mineral allograft materials were inserted in the atrophic posterior mandibles. After four months healing period, bone biopsies in the grafted areas and placement of dental implants were performed. In both cases, panoramic views were taken preoperatively to measure the alveolar bone height for diagnosis, to monitor patient healing, and to evaluate bone healing and bone gain. Results: Sufficient vertical bone height was gained by using the sandwich technique and implants were placed successfully. In radiological evaluation, there was minimal resorption of bone height after the second operation and in histomorphometric evaluation, they showed favorable new bone formation without inflammation in the grafted areas. Conclusion: The sandwich technique can be an effective choice for augmenting vertical bone height in the atrophic mandible. More of cases and long term follow-up are needed to evaluate bone resorption and implant prognosis.

• Restorative Dentistry and Endodontics
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• 제27권5호
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• pp.502-514
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• 2002

The aim of this study was to evaluate the marginal adaptation of direct class II sandwich restoration with packable composites(P-60), resin modified glass ionomer cement(Fuji-II LC), flowable compomer(Dyract Flow), flowable composites(Filtek Flow) in comparison with total bond restorations. In addition, for sandwich restorations, influence of different sandwich techniques was also evaluated. Large butt-joint box typed class II cavites with cervical margins 1mm below the cemento-enamel junction were cut into 70 extracted human molars. The cavities(7 groups, n=10) were filled using a closed/open sandwich restoration or total bond restoration technique with materials according to the manufacturer's recommandation using the single-component bonding agent for each system. Teeth were thermocycled 500 times between 5$^{\circ}C$ and 55$^{\circ}C$ with 30-second dwell time. The teeth were then coated with nail polish 1mm short of the restoration, placed in a 2% methylene blue for 24 hours, and sectioned with diamond wheel. Sections were examined with a stereoscope to determine the extent of microleakage. Dentine /Cementum margins were analyzed for microleakage on scale of 0(no leakage) to 4(entire axial wall) and interface between materials, on scale of 0(no leakage) to 3(axial wall). Results were evaluated with Kruskal Wallis Test, corrected for ties, to determine whether there were statistically significant differences among the seven groups. Pairs of groups were analyzed using the Student-Newman-Keuls Method and Dunn s Method. The results were as follows : 1. All groups showed some micoleakage in cervical portion. But there were no microleakage in interface between materials. 2. Closed sandwich restorations with Fuji-II LC and Filtek Flow had significantly lower leakage rating than total restorations with only P-60. However, open sandwich restorations with Dyract Flow showed significantly higher (P<0.05) 3. Closed sandwich restorations had significantly lower leakage rating than total restorations. However open sandwich restoration s showed significantly higher (P<0.05). 4. Sandwich restorations with Fuji-II LC were iou$.$or leakage than only P-60. Filtek Flow, Dyract Flow. But there were no statistically differences among the materials. From the results above, it could be concluded, closed sandwich restorations was effective in reducing microleakage of class II restorations. The best results showing the least microleakage were for the closed sandwich technique with Fuji-II LC and Filtek Flow.

• Advances in materials Research
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• 제8권4호
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• pp.313-335
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• 2019

The objective of the present paper is to investigate the bending and free vibration behavior of functionally graded material (FGM) sandwich rectangular plates using an efficient and simple higher order shear deformation theory. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The most interesting feature of this theory is that it does not require the shear correction factor. Two common types of FGM sandwich plates are considered, namely, the sandwich with the FGM facesheet and the homogeneous core and the sandwich with the homogeneous facesheet and the FGM core. The equation of motion for the FGM sandwich plates is obtained based on Hamilton's principle. The closed form solutions are obtained by using the Navier technique. A static and free vibration frequency is given for different material properties. The accuracy of the present solutions is verified by comparing the obtained results with the existing solutions.

• 소성∙가공
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• 제7권6호
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• pp.603-609
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• 1998

An aluminium sandwich sheet is the material fabricated by adhering two aluminum panels to one plastic core. When it has the same bending stiffness as an steel panel it is 65% lighter than steel panel and 30% lighter than aluminum panel. Therefore it is notified exclusively as good substitutive materials for steel body to improve fuel efficiency. An aluminium sandwich sheet, however, has a problem of the lower formability than steel in automotive application. In this paper we intend to develop application technologies of an aluminum sandwich sheet for auto body panels from selecting composed materials of aluminium sandwich sheets to fabricating prototype. We selected aluminium sandwich panels fabricated by Hoogovens company. Through formability tests we have designed the hood part on auto body panels and fabricated a mould and a prototype.

• Archives of Plastic Surgery
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• 제49권1호
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• pp.25-28
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• 2022

The authors performed rigid reconstruction using the sandwich technique for full-thickness chest wall defects by using two layers of acellular dermal matrix and bone cement. We assessed six patients who underwent chest wall reconstruction. Reconstruction was performed by sandwiching bone cement between two layers of acellular dermal matrix. In all patients, there was no defect of the overlying soft tissue, and primary closure was performed for external wounds. The average follow-up period was 4 years (range, 2-8 years). No major complications were noted. The sandwich technique can serve as an efficient and safe option for chest wall reconstruction.

• 한국생산제조학회지
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• 제24권2호
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• pp.177-185
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• 2015

This paper describes a weight-reduction design method for the car bodies of a double deck high-speed train (service speed of 300 km/h). The method uses lightweight materials and a topology optimization technique. In this study, aluminum extrusions and sandwich composites were selected as the best materials to reduce the weight of the car body. The topology optimization technique was used to determine which car body parts could be made of the sandwich composites to achieve additional weight savings. The results of the topology optimization analysis showed that sandwich composites could be used for secondary car body members such as the roof and the second underframe. Also, it was found that a car body composed of aluminum extruded parts and sandwich composites could weigh up to 14% less than a car body made of only aluminum extrusions.

• Structural Engineering and Mechanics
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• 제71권2호
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• pp.197-210
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• 2019

Probabilistic buckling behavior of sandwich panel considering random system parameters using a radial basis function (RBF) approach is presented in this paper. The random system properties result in an uncertain response of the sandwich structure. The buckling load of laminated sandwich panel is obtained by employing higher-order-zigzag theory (HOZT) coupled with RBF and probabilistic finite element (FE) model. The in-plane displacement variation of core as well as facesheet is considered to be cubic while transverse displacement is considered to be quadratic within the core and constant in the facesheets. Individual and combined stochasticity in all elemental input parameters (like facesheets thickness, ply-orientation angle, core thickness and properties of material) are considered to know the effect of different degree of stochasticity, ply- orientation angle, boundary conditions, core thickness, number of laminates, and material properties on global response of the structure. In order to achieve the computational efficiency, RBF model is employed as a surrogate to the original finite element model. The stiffness matrix of global response is stored in a single array using skyline technique and simultaneous iteration technique is used to solve the stochastic buckling equations.