Az anyagtudomány és a mechanika szerepe az anyagok és szerkezetek élettartam növelésében = Role of material science and mechanics in lifetime extension of materials and components

A kutatómunka során kifejlesztett, pontosított rúdmodell esetén meghatározásra került a Pasternak-féle ágyazás rugómerevségét. A rúdmodell a középsíkban repedéssel ellátott kompozit rudak rugóállandójára ad pontosított képletet. A különféle korrekciók vagy a próbatest vastagság menti, vagy annak csúsztató rugalmassági moduluszától függnek. A Pasternak-féle rugók esetén a merevség inkább a vastagság menti modulusszal hozható kapcsolatba. A rugók merevségét kombinált végeselem-analitikus módszerrel lett kiszámolva. Az un. DCB próbatestre egy olyan végeselem modellt lett szerkesztve, amelyben a csúsztató rugalmassági modulusz értékét végtelenhez tart. Ily módon kiküszöbölhető azok a hatások, amelyek a csúsztató rugalmassági modulusszal kapcsolatosak Ezután az analitikus modell eredményét egy konstans paraméter beállításával a végeselem modell eredményéhez lett igazítva. A számítást kis és nagy hajlító rugalmassági moduluszú, szén- és üvegszál erősítésű kompozit anyagokra is el lett végezve. Az említett konstans paraméter választott értéke minden esetben nagyon jól illeszkedett a végeselem eredményeihez. A Pasternak-féle rugók merevségének ismeretében a globális módszert még pontosabbá lett. A módszer előnye, hogy pontos és viszonylag egyszerű. | Using the previously developed refined beam model the stiffnes of the Pasternak foundation was determined. The beam model provides an improved compliance expression for delaminated composite beams. The different corrections of the compliance and the strain energy release rate depend on the shear and transverse modulus of the material. It was shown that the Pasternak foundation can be related to the transverse modulus. The stiffness of the Pasternak foundation was determined by a combined analytical-finite element method. This was carried out by using a special DCB specimen of which shear modulus tended to infinity. This way those effetcs, which are related to the shear modulus can be eliminated. Then the value of a constant parameter was chosen in order to reach the best agreement with the finite element model. The computation was performed even for high and low modulus glass and carbon fiber reinforced materials and it was found that the chosen value of the constant satisfies all the cases studied. Using the Pasternak foundation stiffness the global mode decomposition method was improved. The advantages of the method are that it is accurate and easy to apply

Az őrszemnyirokcsomó-áttét kimutatása 4 mm-nél vastagabb melanomában esélyt ad ígéretes adjuváns kezelésre

Bevezetés: Az őrszemnyirokcsomó-biopszia (SNB) jelentősége az előrehaladott – 4 mm-nél vastagabb – melanomák kezelésében eddig vitatott volt a szakirodalomban. Manapság azonban az adjuváns terápiák alkalmazásának előfelté- tele a regionális nyirokcsomók érintettségének szövettani igazolása. Ugyanakkor az SNB szükségességének kritériu- mai Magyarországon sem egységesek, van, ahol jelenleg a vastag melanomák esetén nem végzik el ezt a beavatkozást. Célkitűzés: Klinikánkon az elmúlt években konzekvensen elvégeztük az őrszemnyirokcsomók vizsgálatát 4 mm-nél vastagabb melanomák esetén is, így érdemesnek tartottuk értékelni, hogy ebben a betegcsoportban milyen arányban fordul elő a tájéki nyirokcsomók klinikailag nem, szövettanilag viszont detektálható áttéte. Módszer: A klinikánkon 2007 és 2011 között melanomával diagnosztizált 1133 beteg közül kiválasztottuk azokat a pácienseket, akiknek 4 mm-nél vastagabb primer tumoruk volt, és retrospektíven értékeltük a betegek demográfiai adatait, primer daganatuk klinikai, valamint szövettani jellegzetességeit az őrszemnyirokcsomó szövettani paraméte- reinek függvényében. Eredmények: Az 5 éves időszakban 116 olyan, melanomában szenvedő beteget diagnosztizáltunk, akinél vastag mela- noma került sebészi kimetszésre. 78 páciensnél történt SNB, mely 50 esetben szövettanilag pozitívnak bizonyult. A betegek átlagos életkora közel 58 év volt. Következtetés: Klinikánkon évente tíz olyan, vastag melanomás beteget kezelünk, akinél az őrszemnyirokcsomó szö- vettani pozitivitása alapján igazoltuk a betegség metastaticus stádiumát. Eredményeink és a Nemzeti Rákregiszter adatai alapján akár 100 körülire becsülhető azoknak a pácienseknek a száma Magyarországon, akiknél ezzel a patoló- giai stádiumot meghatározó módszerrel az adjuváns kezelés szükségessége megállapítható. A betegcsoport fiatal életkorát figyelembe véve, hatékony target/immunterápia adjuváns alkalmazásával eredményesebben csökkenthető lehet az elvesztett életévek száma, mint a belszervi metastaticus stádiumban megkezdett kezelésekkel

Reconstruction of Alar-Perialar Defects with a Combined Subcutaneous and Cutaneous Pedicled Rotation-Advancement Nasolabial Flap

During the reconstruction of alar defects involving the upper lip, reconstructive surgeons face the need for various thicknesses of tissues crucial to preserving the facial sulcus which is important for a cosmetically acceptable result. Our aim was to reconstruct the deep perialar and thinner lateral nasal alar defect in a single step procedure with a suitable flap which is reliable, has appropriate blood supply and provides an esthetically good result.Extended alar defect was reconstructed with a combined flap in 10 cases. During the procedure, a subcutaneous pedicle was created and the proximal part of the flap was rotated into the defect as a rotational flap. The procedure and the follow-up have been photo-documented in all cases. Furthermore, the perfusion of the flaps was monitored by means of laser Doppler flowmetry. Postoperative complications were evaluated with a semi-quantitative score and the patients completed a patient satisfaction questionnaire, too.An optimal esthetic result was obtained in all cases after the operation. The lateral nasal alar part of the defect was reconstructed with the thinner proximal part of the flap while the deeper perialar region involving the upper lip was covered with the thicker distal part. The flaps have shown sufficient blood flow after the operation. There was no significant pin cushioning or "trap-door" effect in any case. Mild erythema and edema was found in few cases. The patients were satisfied with the cosmetic result of the intervention.The flap is suitable for the reconstruction of alar defects involving the perialar region. It has the advantage of covering the deeper perialar and the thinner alar defects, whilst eliminating the pin cushioning effect of the conventional subcutaneous island pedicle flaps

A Possible Technique for the Complex Reconstruction of Exposed Breast Implant: Applicability and Microcirculation of the Capsule Flap

AIM OF THE STUDY: Immediate breast reconstruction is often applied after mastectomy. However, inappropriate surgical technique, postoperative radiotherapy and infection may lead to tissue necrosis and implant protrusion. Traditional therapies frequently fail. However, previous data suggested that capsule flaps may be appropriate for the salvage of implants. Our goal was to investigate the usefulness of capsuloplasty in patients with exposed breast implant and to monitor the blood supply of capsule flaps during the operation. MATERIALS AND METHODS: Capsuloplasty was performed in 19 patients with exposed implant. After removal of necrotic tissue, capsulotomy was performed, the planned flap was dissected free, the implant was covered with the flap and the wound was then closed. During operation, the blood flow of the flap was determined by means of laser Doppler flowmetry. Moreover, tissue samples were taken for histology and immunostaining for CD34. RESULTS: The postoperative follow-up showed that capsule flaps survived in each case: no complications were found. The blood flow of the flaps did not change significantly during the intervention as compared with the baseline values. The histology and the immunohistochemistry revealed considerable vascularization and angiogenesis in the flap. CONCLUSIONS: Capsule flaps seem to be appropriate for the salvage of exposed implants and for enhancement of implant cover in the case of thin and injured tissue

Is it Necessary to Perform Sentinel Lymph Node Biopsy in Thin Melanoma? A Retrospective Single Center Analysis

Sentinel lymph node biopsy (SLNB) is a standard procedure for regional lymph node staging and still has the most important prognostic value for the outcome of patients with thin melanoma. In addition to ulceration, SLNB had to be considered even for a single mitotic figure in thin (<1 mm) melanoma according to AJCC7th guideline, therefore, a retrospective review was conducted involving 403 pT1 melanoma patients. Among them, 152 patients suffered from pT1b ulcerated or mitotic rate ≥ 1/ mm2 melanomas according to the AJCC7th staging system. SLNB was performed in 78 cases, of which nine (11.5%) showed SLN positivity. From them, interestingly, we found a relatively high positive sentinel rate (6/78-8%) in the case of thin primary melanomas ˂0.8 mm. Moreover, the presence of regression increased the probability of sentinel positivity by 5.796 fold. After reassessing pT stage based on the new AJCC8th, 37 pT1b cases were reordered into pT1a category. There was no significant relation between other characteristics examined (age, gender, Breslow, Clark level, and mitosis index) and sentinel node positivity. Based on our data, we suggest that mitotic rate alone is not a sufficiently powerful predictor of SLN status in thin melanomas. If strict histopathological definition criteria are applied, regression might be an additional adverse feature that aids in identifying T1 patients most likely to be SLN-positive. After reassessing of pT1b cases according to AJCC8th regression proved to be independent prognostic factor on sentinel lymph node positivity. Our results propose that sentinel lymph node biopsy might also be considered at patients with regressive thin (˂0.8 mm) melanomas

Tumour regression predicts better response to interferon therapy in melanoma patients : a retrospective single centre study.

We hypothesise that regression may have an impact on the effectiveness of adjuvant IFN therapy, based on its role in the host immune response. Our purpose is to investigate regression and ulceration as prognostic factors in case of interferon-alpha (IFN)-treated melanoma patients. We followed 357 IFN-treated melanoma patients retrospectively, investigating progression-free survival (PFS) and overall survival (OS) depending on the presence of ulceration and regression. A Kaplan-Meier analysis was performed, and we used a Cox regression analysis to relate risk factors. The survival function of the Cox regression was used to measure the effect of regression and ulceration on PFS and OS depending on the Breslow thickness (T1-T4) of the primary tumour. Regression was significantly positively related to PFS ( P = 0.0018, HR = 0.352) and OS ( P = 0.0112, HR = 0.380), while ulceration showed a negative effect (PFS: P = 0.0001, HR = 2.629; OS: P = 0.0003, HR = 2.388). They influence survival independently. The most favourable outcome was measured in the regressed/non-ulcerated group, whereas the worse was in the non-regressed/ulcerated one. Of risk factors, Breslow thickness is the most significant predictor. The efficacy of regression is regardless of Breslow thickness, though the more favourable the impact of regression was in the thicker primary lesions. Our results indicate that regression is associated with a more favourable outcome for IFN-treated melanoma patients, whereas ulceration shows an inverse relation. Further studies are needed to analyse the survival benefit of regression in relation to innovative immune checkpoint inhibitors