Analisis Retakan Korosi Tegangan Pada Aluminium Dengan Variasi Pembebanan Dalam Media Korosi Hcl 1m

Stress corrosion cracking [SCC] merupakan kegagalan logam korosi hasil peretakan intergranular atau transgranular dibawah pengaruh antara tegangan tarik dan lingkungan korosif. Bentuk korosi ini lazim sekali dijumpai di lingkungan industri seperti : industri perkapalan, perminyakan, dan industri – industri kontruksi logam. Dalam tugas akhir ini dimaksudkan untuk memahami fenomena Stress Corrosion Cracking secara teoritis dalam aluminium dengan mengkaji pengaruh variasi pembebanan didalam media korosi terhadap pertambahan panjang, lamanya waktu patah dan jenis retak. Pada penelitian ini pengujian menggunakan alat uji Stress Corrosion Cracking, untuk menciptakan suatu kondisi spesimen agar mendapatkan tegangan tarik pada lingkungan yang korosif. Tegangan yang diberikan berupa tegangan tarik yang berasal dari pembebanan statik pada sistem pengungkit. Kondisi korosif dapat dihasilkan dari bak yang diisi dengan larutan HCl. Analisa metalografi dimaksudkan untuk mengamati struktur mikro spesimen uji dan bentuk retak yang terjadi pada spesimen uji setelah dilakukan proses pengujian

Presence of autoimmune disease affects not only risk but also survival in patients with B‐cell non‐Hodgkin lymphoma

Although autoimmune diseases (AIDs) are known to predispose to non‐Hodgkin lymphoma (NHL), their association with NHL prognosis has rarely been investigated. We examined associations between autoimmunity and B‐cell NHL onset by comparing AID history (determined by self‐report and medication review and supplemented by chart review where possible) among 435 adult B‐NHL patients in Hadassah‐Hebrew University Medical Center, diagnosed 2009‐2014, and 414 age‐and‐sex frequency‐matched controls. We examined AIDs as a whole, B‐ and T‐cell–mediated AIDs, and autoimmune thyroid diseases. Among cases, we used Kaplan‐Meier and Cox regression models to assess the association of AID with overall survival and relapse‐free survival, adjusting for prognostically important patient and disease characteristics such as Ki67% staining, International Prognostic Index, rituximab treatment, and histological subgroup. Autoimmune diseases were associated with B‐NHL (odds ratio [OR] = 1.95; 95% confidence interval (CI), 1.31‐2.92), especially AIDs mediated by B‐cell activation (OR = 5.20; CI, 1.90‐14.3), which were particularly associated with marginal zone lymphoma (OR = 19.3; CI, 4.59‐80.9). We found that time to relapse for all B‐NHL patients with AIDs was significantly shorter (mean of 49.21 mo [±3.22]) than among patients without AID (mean of 59.74 mo [±1.62]), adjusted hazard ratio [HRadj] = 1.69 (CI, 1.03‐2.79). Specifically, in patients with diffuse large B‐cell lymphoma, of whom 91.8% had received rituximab, a history of B‐cell–mediated AIDs was associated with shorter relapse‐free survival and overall survival, HRadj = 8.34 (CI, 3.01‐ 23.1) and HRadj = 3.83 (CI, 1.20‐12.3), respectively. Beyond confirming the well‐known association between AIDs and B‐NHL, we found that AID is an adverse prognostic factor in B‐cell lymphoma, associated with a shortened time to relapse, suggesting that there are specific therapeutic challenges in the subgroup of patients suffering from both these diseases. Further work is required to address mechanisms of resistance to standard treatment in the setting of AID‐associated B‐NHL. In the era of immunotherapy, these findings have particular relevance.This study was made possible by the generous support of the American people through the United States Agency for International Development (USAID)/MERC grant no. TA‐MOU‐11‐M31‐025. The contents are the responsibility of the authors and do not necessarily reflect the views of USAID or the United States Government; Israel Science Foundation (ISF) grant no. 877/10; and the Hadassah University Hospital Compensatory Fund. We thank Noemie Cohen for data entry

tLivin displays flexibility by promoting alternative cell death mechanisms.

Livin is a member of the Inhibitor of Apoptosis (IAP) protein family that inhibits apoptosis triggered by a variety of stimuli. We previously demonstrated that while Livin inhibits caspase activity, caspases can cleave Livin to produce a truncated protein, tLivin and that this newly formed tLivin paradoxically induces cell death. However to date, the mechanism of tLivin-induced cell death is not fully understood. In this study, we set out to characterize the form of cell death mediated by tLivin. Here we demonstrate that, unlike most death-promoting proteins, tLivin is a flexible inducer of cell death capable of promoting necrosis or apoptosis in different cell lines. The unusual flexibility of tLivin is displayed by its ability to activate an alternative form of cell death when apoptosis is inhibited. Thus, tLivin can promote more than one form of cell death in the same cell type. Interestingly, in cells where tLivin induces necrosis, deletion of the caspase binding BIR domain results in tLivin-induced apoptosis, suggesting the BIR domain can potentially hamper the ability of tLivin to induce apoptosis. We further elucidate that tLivin activates the JNK pathway and both tLivin-induced apoptosis and necrosis are partially mediated by JNK activity. Acquired resistance to apoptosis, common in many tumors, impinges on the efficiency of conventional anti-cancer agents that function primarily by inducing apoptosis. The ability of tLivin to induce death of apoptosis-compromised cells makes it an attractive candidate for targeted cancer therapy

tLivin-induced apoptosis and necrosis are partially mediated by activation of JNK.

<p>(<b>A</b>) Cells of MelA1 clones were treated with 10 µM SP600125 1 h prior to administration of 2.5 µg/ml dox (where indicated) and harvested after 36 h along with untreated cells (con). Cells were stained with PI and the percent of cell death was measured by flow cytometry. *p<0.05. (<b>B</b>) 293T cells were transiently transfected with the indicated plasmids and harvested 24 h post-transfection along with untransfected cells (con). Cells were stained with PI and the percent of cell death was measured by flow cytometry. (<b>C</b>) 293T cells were transiently transfected with the indicated plasmids, harvested 24 h post-transfection and analyzed by western blot for the protein levels of p-c-JUN, c-JUN, JIP-1, tLivin and GAPDH.</p

tLivin activates the JNK pathway.

<p>(<b>A</b>) 293T cells were either transiently transfected with empty vector (ev), tBID- or tLivin-expressing vectors, treated with 30 µg/ml etoposide for 24 h (etop) or left untreated (con). Cells were harvested at the indicated time points post-transfection and the phosphorylation of JNK, ATF-2 and p38MAPK was analyzed by western blot. (<b>B</b>) Cells of MelA1 clones were harvested at the indicated time points following administration of 2.5 µg/ml dox or following 30 min treatment with 200 nM anisomycin (A), control cells (con) were left untreated. Phosphorylation of JNK and c-JUN was analyzed by western blot. (<b>C</b>) 293T cells were either transiently transfected with empty vector (ev), tLivin- or tLivinΔBIR-expressing vectors, treated with 200 nM anisomycin for 30 min (A) or left untreated (con). Cells were harvested at the indicated time points post-transfection and phosphorylation of JNK and c-JUN was analyzed by western blot.</p

The Oncolytic Activity of Newcastle Disease Virus NDV-HUJ on Chemoresistant Primary Melanoma Cells Is Dependent on the Proapoptotic Activity of the Inhibitor of Apoptosis Protein Livin▿ ‡

Patients with advanced melanoma usually do not benefit from conventional chemotherapy treatment. There is therefore a true need for a new kind of therapy for melanoma. One factor responsible for the poor prognosis of melanoma is the inhibitor of apoptosis protein (IAP) family member Livin. In this study, we applied a novel approach for the treatment of melanoma, using a unique strain of the oncolytic Newcastle disease virus (NDV-HUJ). We found that, unlike chemotherapeutic drugs, NDV-HUJ, a one-cycle replicating virus, overcomes the resistance to apoptosis of melanoma primary cultures that over express the Livin protein. In contrast, melanoma tumor cells that do not express Livin are relatively resistant to NDV-HUJ treatment. Furthermore, we show that NDV-HUJ-induced oncolysis is attributed to the dual function of Livin: although Livin inhibits apoptosis through the inhibition of caspases, under the robust apoptotic stimulation of NDV-HUJ, caspases can cleave Livin to create a truncated protein with a paradoxical proapoptotic activity. Thus, NDV-HUJ is a potent inducer of apoptosis that can overcome the antiapoptotic effect of Livin and allow cleavage of Livin into the proapoptotic tLivin protein. Moreover, the results indicate that the interferon system, which is functional in melanoma, is not involved in NDV-induced oncolysis. Taken together, our data offer the possibility of a new viral oncolytic treatment for chemoresistant melanoma

tLivin induces apoptosis of MelA1 cells.

<p>Cells of MelA1 clones were treated with 2.5 µg/ml dox and harvested at the indicated time points. Con, untreated cells; sts, cells treated with 0.5 µM staurosporine for 10 h. (<b>A</b>) Cells were stained with PI and the percent of cell death was measured by flow cytometry (top). Cells were analyzed for tLivin and GAPDH protein levels by western blot (bottom). (<b>B</b>) Cleavage of caspase 3 and PARP was analyzed by western blot. (<b>C</b>) DNA content was analyzed by flow cytometry.</p

tLivin induces apoptosis of A549 cells.

<p>Cells of A549 clones were treated with 2.5 µg/ml dox and harvested at the indicated time points. Con, untreated cells; etop, cells treated with 30 µg/ml etoposide for 48 h. (<b>A</b>) Cells were stained with PI and the percent of cell death was measured by flow cytometry (top). Cells were analyzed for tLivin and GAPDH protein levels by western blot (bottom). (<b>B</b>) Cleavage of caspase 3 and PARP was analyzed by western blot. (<b>C</b>) DNA content was analyzed by flow cytometry. (<b>D</b>) Cells were treated with 50 µM zVAD-fmk 1 h prior to addition of dox, harvested after 48 h, stained with PI and the percent of cell death was measured by flow cytometry. *p<0.05. (<b>E</b>) Cells were treated with 50 µM zVAD-fmk 1 h prior to addition of dox and harvested after 48 h. Each sample was divided into three aliquots and analyzed for cleavage of caspase 3 by western blot and for the percent of PI positive cells and DNA content by flow cytometry.</p

tLivin activates an alternative form of cell death when apoptosis is inhibited.

<p>Cells of MelA1 clones were treated with 75 µM zVAD-fmk 1 h prior to addition of 2.5 µg/ml dox or 30 µM cisplatin and harvested after 36 h along with untreated cells (con). (<b>A</b>) Cells were stained with PI and the percent of cell death was measured by flow cytometry. *p<0.05. (<b>B</b>) Cells from each sample were divided into three aliquots and analyzed for cleavage of caspase 3 by western blot and for the percent of PI positive cells and DNA content by flow cytometry.</p