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In the present work, optimum A-TIG welding process parameters have been determined using the design of experiments approach to achieve the desired depth of penetration (DOP) during welding of duplex stainless steel (DSS) alloy 2205. The design matrix for welding experiments was generated using the central composite design of response surface methodology. Bead-on-plate welds were made on 10 mm thick DSS alloy 2205 plates to generate data and to study the influence of process parameters on DOP. ANOVA analysis was carried out to determine the significance of the process parameters. Current was found to be a significant parameter influencing DOP. A second-order response surface model was developed to predict the response for the set of given input process parameters. Then, numerical and graphical optimization was performed to obtain the maximum DOP using desirability approach. Validation of the model showed good agreement between the predicted and actual values of DOP.

The thermo-elasto-plastic analysis of type 316L stainless steel sheets during pulsed Nd-YAG Laser-beam welding was carried out using three different heat sources employing SYSWELD. The three heat sources employed were 3D conical, 3D conical with double ellipsoidal and 3D conical with cylindrical shell. The simulated thermal cycles, residual stresses and distortion were validated by experiments. The simulated thermal cycles were validated by thermal cycles measured using thermocouples at pre-defined positions. The simulated residual stress profiles were validated by residual stress profiles measured using ultrasonic technique (UT). The simulated distortion values were validated by distortion measured using vertical height gauge. There was good agreement between the model predictions and experimental measurements. It was found that the model using 3D conical with cylindrical shell heat source predicted the thermal cycles, residual stresses and distortion more accurately compared to that of the other heat sources.

In the present study, 12 mm thick double side square butt joint was fabricated on 2.25Cr-1Mo (P22) steel plates using A-TIG welding process with in-house developed activated fluxes. Microstructure and mechanical properties of the weld joint were characterized. Effect of post weld heat treatment (PWHT) on the impact toughness was studied. In the as-welded condition toughness was found to be 133 J. There was no proeutectoid ferrite in the weld. After PWHT, the toughness of weld was increased to 177 J due to dissolution and coarsening of existing precipitates. A-TIG weld joint of 2.25Cr-1Mo steel exhibited high hardness and good impact toughness in the as welded condition.

Optimization of A-TIG welding process parameters for 9Cr-1Mo steel has been carried out using response surface methodology (RSM) and genetic algorithm (GA). RSM has been used to obtain the design matrix for generating data on the influence of process parameters on the response variables. A second-order response surface model was developed for predicting the response for the set of given input variables. Then, numerical and graphical optimization was performed using RSM to obtain the target depth of penetration (DOP) and heat-affected zone (HAZ) width using desirability approach. Multiple regression models were developed based on the generated data, and then the models were used in GA to determine the optimum process parameters for achieving the target DOP and HAZ width. GA-based models employed two different selection processes. Both the RSM- and GA-based models suggested a number of solutions in terms of process parameters, and the identified solutions were validated by experiments. GA-based model employ...

Effect of preheat on the thermal cycles, residual stress, and distortion during autogenous GTA welding of Grade P91 steel has been analyzed using FEM. Phase transformation effect on the residual stresses is also analyzed. Thermomechanical analysis has shown that preheat reduced the peak temperatures, cooling rate, and the distortion values. The phase transformation involving martensite during cooling resulted in typical “M” shaped residual stress profile with a reduction in peak tensile residual stress value and a wider distribution of residual stress. There is good agreement between the predicted and measured thermal cycles, residual stresses, and distortion of the P91 steel weld joint.

The role of Mithramycin as an anticancer drug has been well studied. Sarcoma is a type of cancer arising from cells of mesenchymal origin. Though incidence of sarcoma is not of significant percentage, it becomes vital to understand the role of Mithramycin in controlling tumor progression of sarcoma. In this article, we have analyzed the global gene expression profile changes induced by Mithramycin in two different sarcoma lines from whole genome gene expression profiling microarray data. We have found that the primary mode of action of Mithramycin is by global repression of key cellular processes and gene families like phosphoproteins, kinases, alternative splicing, regulation of transcription, DNA binding, regulation of histone acetylation, negative regulation of gene expression, chromosome organization or chromatin assembly and cytoskeleton.

Research on toxin-antitoxin loci (TA loci) is gaining impetus due to their ubiquitous presence in bacterial genomes and their observed roles in stress survival, persistence and drug tolerance. The present study investigates the expression profile of all the seventy-nine TA loci found in Mycobacterium tuberculosis. The bacterium was subjected to multiple stress conditions to identify key players of cellular stress response and elucidate a TA-coexpression network. This study provides direct experimental evidence for transcriptional activation of each of the seventy-nine TA loci following mycobacterial exposure to growth-limiting environments clearly establishing TA loci as stress-responsive modules in M. tuberculosis. TA locus activation was found to be stress-specific with multiple loci activated in a duration-based response to a particular stress. Conditions resulting in arrest of cellular translation led to greater up-regulation of TA genes suggesting that TA loci have a primary role in arresting translation in the cell. Our study identifed higBA2 and vapBC46 as key loci that were activated in all the conditions tested. Besides, relBE1, higBA3, vapBC35, vapBC22 and higBA1 were also upregulated in multpile stresses. Certain TA modules exhibited co-activation across multiple conditions suggestive of a common regulatory mechanism.

Background Acute viral hepatitis E (AVH-E) can often result in acute liver failure (ALF) during pregnancy. microRNAs serve as mediators in drug induced liver failure. We investigated their role as a biomarker in predicting ALF due to HEV (ALF-E). Methods We performed next generation sequencing and subsequent validation studies in PBMCs of pregnant (P) self limiting AVH-E, ALF due to HEV (ALF-E) and compared with AVH-E in non-pregnant (NP) females and healthy controls. Findings Eleven microRNAs were significantly expressed in response to HEV infection; importantly, miR- 431, 654, 1468 and 4435, were distinctly expressed in pregnant self-limiting AVH-E and healthy females (p = 0.0005), but not in ALF-E. Sixteen exclusive microRNAs differentiated ALF-E from self limiting AVH-E in pregnant females. miR-450b which affects cellular proliferation and metabolic processes through RNF20 and SECB was predominanlty upregulated and correlated with poor outcome (ROC 0.958, p = 0.001). Interpretation Our results reveal that a specific microRNA profile can predict fatality in ALF-E in pregnancy. These microRNAs could be exploited as prognostic biomarkers and help in the development of new therapeutic interventions.

Hepatitis B virus (HBV) can manipulate the microRNA (miRNA) regulatory networks in infected cells to create a permissive environment for viral replication, cellular injury, disease onset, and its progression. The aim of the present study was to understand the miRNA networks and their target genes in the liver of hepatitis B patients involved in HBV replication, liver injury, and liver fibrosis. We investigated differentially expressed miRNAs by microarray in liver biopsy samples from different stages of HBV infection and liver disease (immune-tolerant [n = 8], acute viral hepatitis [n = 8], no fibrosis [n = 16], early [F1+F2, n = 19] or late [F3+F4, n = 14] fibrosis, and healthy controls [n = 7]). miRNA expression levels were analyzed by unsupervised principal component analysis and hierarchical clustering. Analysis of miRNA-mRNA regulatory networks identified 17 miRNAs and 18 target gene interactions with four distinct nodes, each representing a stage-specific gene regulation during disease progression. The immune-tolerant group showed elevated miR-199a-5p, miR-221-3p, and Let-7a-3p levels, which could target genes involved in innate immune response and viral replication. In the acute viral hepatitis group, miR-125b-5p and miR-3613-3p were up, whereas miR-940 was down, which might affect cell proliferation through the signal transducer and activator of transcription 3 pathway. In early fibrosis, miR-34b-3p, miR-1224-3p, and miR-1227-3p were up, while miR-499a-5p was down, which together possibly mediate chronic inflammation. In advanced fibrosis, miR-1, miR-10b-5p, miR-96-5p, miR-133b, and miR-671-5p were up, while miR-20b-5p and miR-455-3p were down, possibly allowing chronic disease progression. Interestingly, only 8 of 17 liver-specific miRNAs exhibited a similar expression pattern in patient sera. Conclusion miRNA signatures identified in this study corroborate previous findings and provide fresh insight into the understanding of HBV-associated liver diseases which may be helpful in developing early-stage disease diagnostics and targeted therapeutics. (Hepatology 2018;67:1695-1709).

The thermal analysis of Modified 9Cr-1Mo steel plate during GTA welding is carried out using finite element method employing SYSWELD software. First, the simulation of bead on plate welds for 16 varying process parameter conditions by employing a double ellipsoidal heat source was carried out. Simulated bead on plate weld bead dimensions for the 16 welds were compared with the actual bead dimensions obtained experimentally. Then the simulation of GTA welding of square butt joint on 3 mm thick plates of dimensions 300 × 125 × 3 mm was carried out. The simulated thermal profiles were validated using thermocouple measurements. There was good agreement between the predicted and measured weld bead profiles and thermal cycles for square butt joint. The investigation on the effect of copper back up plate on the peak temperature and the cooling rate has revealed that the peak temperature decreased by 147 °C and the cooling rate increased by 35%.

Modified 9Cr-1Mo steel plates of 10 mm thickness have been fabricated by double side welding procedure employing A-TIG welding process. Even after regular post weld heat treatment (PWHT), the impact toughness of A-TIG weld joint was found to be lower compared to that of conventional TIG weld joint. Therefore, post weld heat treatments of longer durations were considered for improving the toughness. Accordingly, in the present study, PWHT was carried out on A-TIG weld joints at 760 °C for 4, 6 and 8 h duration to optimize the tempering time for improving the toughness by careful study of the microstructures. It was observed that the A-TIG weld joint subjected to PWHT at 760 °C for 4 h exhibited higher hardness (410 VHN) and lower toughness (39 J) resulting from partial tempering of as-welded martensitic microstructure. The weld joint that was tempered at 760 °C for 6 h exhibited fully tempered martensite microstructure with extensive precipitation of M23C6 type carbide. The joint in this condition exhibits good impact toughness to a value of 96 J. After 8 h of tempering at 760 °C, the hardness decreased to a low value of 170 VHN and the toughness value increased beyond 200 J. It was attributed to over tempering of matensite resulting in coarsening of M23C6 precipitates and reduction in dislocation density. A-TIG weld joint with fully tempered martensite microstructure exhibit an average toughness value of 96 J and minimum single value of 75 J. Therefore, PWHT at 760 °C for 6 h was identified as the optimum tempering treatment for improving the impact toughness in mod. 9Cr-1Mo steel A-TIG weld joint.

The effect of activated tungsten inert gas welding process parameters on the weld bead geometry of duplex stainless steel alloy 2205 is analyzed and discussed in this research paper. The welding design matrix for conducting the experiments is made using the central composite design of response surface methodology (RSM). The input process parameters (current, torch speed, and arc gap) are varied at five levels which results in 21 experimental trials. Bead-on-plate welds are made on 10-mm-thick duplex stainless steel plates. The responses (depth of penetration, area of depth of penetration, bead width, bead height, heat-affected zone width, and aspect ratio) are measured after conducting the experiments. A second-order response surface model is developed for predicting the responses for the set of given input parameters. Then, multi-objective optimization is performed to obtain the desired weld bead geometry using desirability approach.

Retinoblastoma (RB) is a primary childhood eye cancer. HMGA2 shows promise as a molecule for targeted therapy. The involvement of miRNAs in genome-level molecular dys-regulation in HMGA2-silenced RB cells is poorly understood. Through miRNA expression microarray profiling, and an integrated array analysis of the HMGA2-silenced RB cells, the dysregulated miRNAs and the miRNA-target relationships were modelled. Loop network analysis revealed a regulatory association between the transcription factor ( SOX5) and the deregulated miRNAs imiR-29a, miR-9*, miR-9-3). Silencing of HMGA2 deregulated the vital oncomirs ( miR-7, miR-331, miR-26a, miR-221, miR-17∼92 and miR-106b∼25) in RB cells. From this list, the role of the miR-106b∼25 cluster was examined further for its expression in primary RB tumor tissues (n = 20). The regulatory targets of miR-106b∼25 cluster namely p21 (cyclin-dependent kinase inhibitor) and BIM (pro-apoptotic gene) were elevated, and apoptotic cell death was observed, in RB tumor cells treated with the specific antagomirs of the miR-106b∼25 cluster. Thus, suppression of miR-106b∼25 cluster controls RB tumor growth. Taken together, HMGA2 mediated anti-tumor effect present in RB is, in part, mediated through the miR-106b∼25 cluster.

In this research, thermoelastoplastic analysis using finite element modeling was carried out to study the thermomechanical behavior of 316LN stainless steel during autogenous tungsten inert gas welding. The efficiency of nondestructive testing was explored by validating the numerical simulations. Online temperature measurements were performed using infrared thermography. A detailed study of surface and bulk residual stress was performed using numerical modeling, and stress profiles were validated using X-ray diffraction and ultrasonic testing, respectively. Distortion analysis was validated using mechanical measurement. Nondestructive testing was efficiently used to validate the numerically predicted thermo-mechanical behavior of welded components.

The objective of this work is to carry out thermo-elasto-plastic analysis of pulsed Nd-YAG laser-beam butt welding of 304L Stainless Steel sheets using Finite Element Modelling. Thermo-mechanical analysis was done by using commercial Finite Element software SYSWELD. Thermal analysis provided thermal cycles and weld bead geometry. Then using thermo-mechanical analysis, residual stresses and distortion values were estimated. In order to validate the model predictions, a single pass autogenous welding with pulsed laser beam was performed on 304L stainless steel sheets. Thermocouples were used to record temperatures at different places close to the fusion line. Vertical displacements after welding were measured using Vertical height gauge equipment. The longitudinal residual stress after welding was measured using an ultrasonic technique. Metallography was employed to view the cross sections of the weld bead. The Finite Element Analysis results were then compared with experimental results. Thermal cycles, distortion and residual stresses obtained in FEA and experiments were found to be in good agreement.

Bead on plate activated tungsten inert gas (A-TIG) welding of duplex stainless steel (DSS) 2205 was performed to determine the thermal history, temperature distribution and the weld bead geometry. Finite element (FE) simulations were carried out using the software, SYSWELD considering the temperature dependent thermal and mechanical properties of the base material. A 3D double ellipsoidal heat source was employed for the non-linear thermal analysis. The transient temperature distribution, weld bead profile, weld bead dimensions, depth of penetration and bead width were calculated by FE simulation. The simulated weld bead profile was compared with the experimentally measured profile and found to be in agreement.

In this research work, thermo-elasto-plastic analysis using finite element modeling (FEM) was carried out to study the thermo mechanical behavior of AISI 304L stainless steel plate of 3 mm thick during the autogenous tungsten inert gas welding. Sysweld software has been employed for simulating the temperature distribution, residual stresses and distortion. Physical and mechanical properties of 304 L stainless steel required for simulation were obtained from the literature. Bead-on-plate experiment was carried out at 140 A and 120 mm/min for obtaining weld bead dimensions which are required for heat source fitting in the simulation. Heat source parameters in the simulation were frozen when the bead profile obtained in the simulation matched with the actual bead profile. Then thermal cycles were simulated with the frozen heat source parameters. The thermal cycles and the peak temperatures predicted by the model were compared with that of the experimentally measured values. There was good agreement between the predicted and measured values. The experimentally validated thermal model was further used for simulating residual stresses and distortion. The calculated residual stress profile was validated using experimentally measured residual stress profiles using an Ultrasonic technique. There was good agreement between the predicted and measured residual stress profiles. The simulated distortion values were compared with measured distortion values using height gauge. There was good agreement between the simulated and measured distortion values. The Finite Element model developed for simulating the TIG welding of 304 L stainless steel predicted the thermal cycles, residual stresses and distortion with minimum error.

In this work, the effect of activated tungsten inert gas welding process parameters on the depth of penetration of super duplex stainless steel alloy 2507 has been analyzed using response surface methodology. The design matrix for conducting the experiments was generated using the central composite rotatable design of response surface methodology of design of experiments. The input process parameters like current, torch speed and arc gap were varied at five levels. Based on the generated design matrix, bead-on-plate welds were made on 10-mm-hick super duplex stainless steel plate. The depth of penetration, which is the response in the present analysis, was measured on the samples. A second-order response surface model was developed. Then, response optimization was performed for obtaining the maximum depth of penetration using desirability approach. The validation of the model showed good agreement between the predicted and actual values of depth of penetration.

The mechanisms underlying the differentiation of Mesenchymal stem cells (MSCs) toward neuronal cell type are not clearly understood. Earlier, we reported that laminin-1 induces neurite outgrowth in human MSCs via c-Jun/AP-1 activation through ERK, JNK, and Akt pathways. In this study, we demonstrate that laminin-1 increases the expression of proneural gene, neuroD1 and induces the expression of immediate-early biomarkers of neuronal cell-programming-Egr1, Egr3, PC3, and PC4. Gene expression profiling of MSCs cultured on laminin-1 and Poly-l-lysine for 12 h revealed differential regulation of 267 genes (>1.5 fold, p < 0.05), predominantly in the category of nervous system development and affected the pathways involved in TGF-β/TNF-α signaling, regulation of MAPK and JNK cascade. Data for 11 selected genes related to nervous system development was validated by real time PCR. Transcriptional regulatory network analysis revealed c-Jun as the key transcription factor regulating majority of differentially expressed genes and identified Disrupted in schizophrenia 1, as a novel target of c-Jun. Modeling and analysis of biological network showed selective induction of Growth Arrest and DNA damage 45 (GADD45B) and repression of NF-κB inhibitor A (NFκBIA). Collectively, our findings provide the basis for understanding the molecular mechanisms associated with laminin-1-induced neurogenic expression in MSCs.

Modified 9Cr-1Mo (P91) steel is widely used in the construction of power plant components. In the present study, a comparative study on influence of activated flux tungsten inert gas (A-TIG), and gas tungsten arc (GTA) welding processes on the microstructure and the impact toughness of P91 steel welds was carried out. P91 steel welds require a minimum of 47 J during the hydrotesting of vessels as per the EN1557: 1997 specification. Toughness of P91 steel welds was found to be low in the as-weld condition. Hence post-weld heat treatment (PWHT) was carried out on weld with the objective of improving the toughness of weldments. Initially as per industrial practice, PWHT at 760 °C – 2 h was carried out in order to improve the toughness of welds. It has been found that after PWHT at 760 °C – 2 h, GTA weld (132 J) has higher toughness than the required toughness (47 J) as compared with A-TIG weld (20 J). The GTA weld has higher toughness due to enhanced tempering effects due to multipass welding, few microinclusion content and absence of δ-ferrite. The A-TIG weld requires prolonged PWHT (i.e. more than 2 h at 760 °C) than GTA weld to meet the required toughness of 47 J. This is due to harder martensite, few welding passes that introduces less tempering effects, presence of δ-ferrite (0.5%), and more alloy content. After PWHT at 760 °C – 3 h, the toughness of A-TIG weld was improved and higher than the required toughness of 47 J.

Microarrays have allowed gene expression profiling to progress from the gene level to the genome level, and oligonucleotide microarrays have become the platform of choice for large-scale, targeted gene expression studies. cDNA arrays and spotted oligonucleotide arrays have gradually given way to in situ synthesized oligonucleotide-based DNA microarrays for whole-genome expression profiling. With the identification of new coding and regulatory sequences, it is imperative that microarrays be updated to enable more complete expression profiling of genomes. We report here a new in situ synthesized oligonucleotide-based microarray platform for Mycobacterium tuberculosis that has been updated for the latest genome information and incorporates hitherto unannotated genes with described biological functions. This microarray has greater coverage of mycobacterial genes than any other array reported to date. We have also evaluated different labeled-target preparation methods and hybridization conditions for this new microarray to obtain high quality data and reproducible results. The new design has been rigorously validated for its specificity and performance using samples isolated from mycobacteria grown under different environment conditions. Further, the quality of the generated data has been compared with published data and is superior to that obtained using spotted oligonucleotide microarrays.

Creep rupture behavior of 9Cr–1.8W–0.5Mo–VNb (ASME grade 92) ferritic steel weld joint fabricated by activated TIG (A-TIG) welding process have been investigated at 923 K over a stress range of 80–150 MPa. The weld joint was comprise of fusion zone, heat affected zone (HAZ) and base metal. The HAZ consisted of coarse prior-austenite grain (CGHAZ), fine prior-austenite grain (FGHAZ) and intercritical (ICHAZ) regions in an order away from the fusion zone to base metal. A hardness trough was observed at the outer edge of HAZ of the weld joint. TEM investigation revealed the presence of coarse M23C6 precipitates and recovery of martensite lath structure into subgrain in the ICHAZ of the weld joint, leading to the hardness trough. The weld joint exhibited lower creep rupture lives than the base metal at relatively lower stresses. Creep rupture failure location of the weld joint was found to shift with applied stress. At high stresses fracture occurred in the base metal, whereas failure location shifted to FGHAZ at lower stresses with significant decrease in rupture ductility. SEM investigation of the creep ruptured specimens revealed precipitation of Laves phase across the joint, more extensively in the FGHAZ. On creep exposure, the hardness trough was found to shift from the ICHAZ to FGHAZ. Extensive creep cavitation was observed in the FGHAZ and was accompanied with the Laves phase, leading to the premature type IV failure of the steel weld joint at the FGHAZ.

In this research work, Finite Element Modeling (FEM) using SYSWELD was carried out to predict thermal cycles, residual stresses and distortion in type 316 LN stainless steel weld joint made by TIG welding process. The numerically predicted thermal cycles and temperature distribution were validated using Infrared (IR) Thermography. The model predictions of the surface and bulk residual stress profiles were validated using X-ray Diffraction (XRD) and Ultrasonic Testing (UT) respectively. Distortion analysis was also performed and validated using digital height gauge measurement. IR thermography was found to be a good tool for validating the model predictions of the temperature distribution in the weld joint. There was good agreement between the model predictions and the experimentally observed values of temperature, residual stresses and distortion. Therefore, the numerical modeling in combination with non-destructive methods provides an efficient approach for predicting the effect of welding process on the weld attributes.

Integrity of tempered martensitic grade 92 (9Cr-1.8W-0.5Mo-VNb) steel welded joint has been assessed by carrying out creep test at 923 K over a wide stress range. The failure location in the joint was found to shift from base metal to heat affected zone (HAZ) of the weld joint with decrease in applied stress. The HAZ of the weld joint consisted of coarse prior-austenite grain (CGHAZ), fine prior-austenite grain (FGHAZ) and intercritical (ICHAZ) regions in a sequence from the fusion boundary to unaffected base metal. The failure was associated with localized creep deformation coupled with creep cavitation. To have a better insight to the creep failure behaviour of the joint, the different microstructural constituents of HAZ of the joint has been simulated. Creep and tensile tests were carried out on the simulated HAZs specimens. The steel suffered degradation in creep rupture strength on subjecting heating in the intercritical (between Ac 1 and Ac 3 ) (ICHAZ) as well as at temperature just above the Ac 3 (FCHAZ). The extensive creep cavitation has been observed in the simulated FGHAZ of the joint. Similarly, localized extensive creep cavitation and precipitation of tungsten rich Laves phase has been observed in the FGHAZ of the weld joint. This caused the type IV failure in the FGHAZ of the weld joint. The integrity of grade 92 steel joint under creep condition is governed by the above microstructural modifications of the steel in HAZ by weld thermal cycle.

This study investigates dissimilar metal weldments between P91 steel and AISI 316 L austenitic stainless steel fabricated by activated TIG welding (A-TIG) with and without the use of interlayers of Incoloy 800 and Inconel 600. Through thickness penetration in 8 mm thick plates was achieved in a single pass A-TIG welding using a pre-coated mixture of metallic oxides. Hot cracking was eliminated in A-TIG weld joints in contrast to conventional TIG weld joints without flux. Fully martensitic structure was observed in the weld metal developed without the use of interlayer. Microstructural modifications were achieved with the use of interlayers. The weldment with Incoloy 800 interlayer exhibited martensitic-austenitic structure whereas fully austenitic structure was observed with Inconel 600 interlayer. Interlayers improved impact toughness and ductility of the weld joints without significant loss of tensile strength. The effect of interlayers on carbon migration after aging treatment (620 °C/500 h) was evaluated with the help of thermodynamic simulations and it was observed that the use of interlayers reduced the severity of carbon migration.

Reduced Activation Ferritic-Martensitic steels (RAFM) are chosen as the candidate material for structural components in fusion reactors. Gas Tungsten Arc (GTA) welding is one of the candidate process for fabricating the structural components made of RAFM steel. A variant of GTA welding process called as Activated Tungsten Inert Gas (A-TIG) welding has been reported to overcome the limitations of GTA welding and enhance creep rupture life in F–M steels. In the present work, 10 mm thick RAFM steel is welded by conventional TIG and A-TIG welding processes and the effect of welding techniques on the microstructure and mechanical properties are compared. Post Weld Heat Treatment (PWHT) conditions are optimized in A-TIG weld joint to get improvement in impact toughness values. TEM investigation on weld metals revealed that the martensite lath and prior austenitic grain boundaries are decorated with M23C6 precipitates and the lath size was in the range of 0.3 -0.4 μm. Very fine MX precipitates are seen in intra martensite laths and very fine sub grain formation was observed after tempering treatment. Hardness and strength properties are higher for A-TIG weld joint while ductility is similar for both the weld joints. An impact toughness of 155 J was obtained in the A-TIG weld joint on full size sample.

Response surface methodology (RSM) is a mathematical and statistical technique useful for the modeling and optimization of processes in which a response of significance is influenced by a number of process parameters called input variables. The major concern faced by fabrication engineers during activated tungsten inert gas (A-TIG) welding is the selection of the optimum combination of input variables for achieving the desired weld bead geometry. In this research work, the optimization of A-TIG welding process parameters for P92 (9Cr-0.5Mo-1.8W-VNb) steel have been carried out using RSM. The design matrix for conducting experiments was generated using the central composite design of RSM. The four input process variables, such as welding current, torch speed, arc gap, and electrode tip angles, are varied at five levels. A-TIG bead-on-plate welds were made on a 10 mm-thick P92 steel plate as per the combination of input parameters given by the design matrix. Weld bead geometry, such as the depth of penetration, bead width, and width of the heat-affected zone, were measured and recorded as responses. Second-order response surface models were developed for predicting the response for the set of given input process parameters. Moreover, the response optimization was carried out for obtaining the maximum depth of penetration, minimum bead width, and target heat-affected zone width using the desirability approach. The validation experiments were carried out on the determined optimized process parameters, and it was found that there was good agreement between the predicted weld bead dimensions and actual values obtained during the experiments.

The objective of the present investigation involves studying the microstructure and mechanical properties of duplex stainless steel (DSS) alloy 2205 and super DSS (SDSS) alloy 2507 weld joints fabricated by tungsten inert gas (TIG) welding and its variant, activated TIG (A-TIG) welding. Square butt weld joints were fabricated from 10-mm-thick plates of DSS and SDSS using single pass A-TIG and multi-pass TIG welding processes. The filler wire ER2209 was used for multi-pass TIG welding of DSS 2205, and ER2594 filler wire was used for multi-pass TIG welding of SDSS 2507. The microstructure in the A-TIG weld metals was found to be coarser, which was caused by high peak temperatures during A-TIG welding. The microstructures exhibited different forms of austenite, including grain boundary allotriomorphs, Widmanstatten side plates, and intragranular precipitates in the weld metal. In the A-TIG weld metals, the microstructure exhibited a balanced ferrite-to-austenite ratio. The hardness values of multi-pass TIG weld joints were higher compared to A-TIG weld joints. The tensile and yield strengths of multi-pass TIG weld joints were higher compared to A-TIG weld joints, which was mainly due to higher delta ferrite content and finer microstructure. The toughness values obtained by Charpy impact testing were higher in A-TIG weld joints compared with multi-pass TIG weld joints at room temperature, which was mainly due to the balanced ferrite-to-austenite ratio in the weld microstructure. However, at subzero temperatures, the A-TIG weld joints exhibit lower impact toughness because of their coarser weld metal structure.

In the present study, A-TIG welding was carried out on grade 91 steel plates of size 220 × 110 × 10 mm using the in-house developed activated flux to produce butt-joints. The room-temperature impact toughness of the A-TIG as-welded joint was low due to the presence of untempered martensite matrix despite the low microinclusion density caused by activated flux and also low δ-ferrite (

PurposeManagement of Retinoblastoma (RB), a pediatric ocular cancer is limited by drug-resistance and drug-dosage related side effects during chemotherapy. Molecular de-regulation in post-chemotherapy RB tumors was investigated.Materials and MethodscDNA microarray analysis of two post-chemotherapy and one pre-chemotherapy RB tumor tissues was performed, followed by Principle Component Analysis, Gene ontology, Pathway Enrichment analysis and Biological Analysis Network (BAN) modeling. The drug modulation role of two significantly up-regulated genes ( P≤0.05) — Ect2 (Epithelial-cell-transforming-sequence-2), and PRAME (preferentially-expressed-Antigen-in-Melanoma) was assessed by qRT-PCR, immunohistochemistry and cell viability assays.ResultsDifferential up-regulation of 1672 genes and down-regulation of 2538 genes was observed in RB tissues (relative to normal adult retina), while 1419 genes were commonly de-regulated between pre-chemotherapy and post- chemotherapy RB. Twenty one key gene ontology categories, pathways, biomarkers and phenotype groups harboring 250 differentially expressed genes were dys-regulated ( EZH2, NCoR1, MYBL2, RB1, STAMN1, SYK, JAK1/2, STAT1/2, PLK2/4, BIRC5, LAMN1, Ect2, PRAME and ABCC4). Differential molecular expressions of PRAME and Ect2 in RB tumors with and without chemotherapy were analyzed. There was neither up- regulation of MRP1, nor any significant shift in chemotherapeutic IC50, in PRAME over-expressed versus non-transfected RB cells.ConclusionCell cycle regulatory genes were dys-regulated post-chemotherapy. Ect2 gene was expressed in response to chemotherapy-induced stress. PRAME does not contribute to drug resistance in RB, yet its nuclear localization and BAN information, points to its possible regulatory role in RB.

It is imperative to understand the mechanisms of growth and development in higher plants for improving plant adaptation during different developmental stages. Plant microRNAs (miRs) play crucial regulatory roles in various developmental processes. As many as 15 miR families having multiple members are known to regulate plant development, yet the spatio-temporal expression patterns of individual members are not fully characterized. It is likely that different members of miR families can make specific contributions to the spatio-temporal control of targets. To understand the functional complexity of miRs and the amount of degeneracy existing in miR-mediated regulation of differentiated but developing tissues, we have identified the Osa-miR-sequences that are expressed in specific tissues. We adopted the approach of comparative miR profiling using next-generation sequencing technology followed by experimental validation. It was observed that 59 Osa-miR-sequences show tissue-preferential expression in local basmati rice variety; while 126 miRs belonging to 81 families are differentially regulated in these tissues. The 21 nt miRs were predominant in all tissues, but the 24 nt miRs were the most abundantly expressed. This indicates that target cleavage and chromatin state regulation are involved in organ development. This study also identified the expression patterns of individual members of Osa-miR families that were common and divergent between the indica and japonica rice varieties. The expression patterns of the predicted targets were also analyzed. The possible implications of the miR distribution patterns with respect to the regulation of their respective targets are discussed. J. Cell. Biochem. 114: 2071–2081, 2013. © 2013 Wiley Periodicals, Inc.

In order to develop remote welding process methodologies, it is first important to develop computational methodologies employing soft computing techniques for predicting weld bead width and depth of penetration using a real time vision sensor during welding. Welding being a thermal processing method, sensing using infra-red (IR) camera is most extensively employed for monitoring and control of welding process. In the present work, attempt has been made to develop predictive methodologies using hybrid soft computing techniques for accurately estimating the weld bead width and depth of penetration from the IR thermal image of the weld pool. IR thermal images have been recorded in real time during A-TIG welding of 6 mm thick type 316 LN stainless steel weld joints with varying current values to produce different depth of penetration. From the acquired IR images, hot spot was identified by image segmentation using the cellular automata image processing algorithm for the first time. The current and the four extracted features from the hot spot of the IR thermal images were used as inputs while the measured bead width and depth of penetration were chosen as the output of the respective adaptive neuro fuzzy inference system and artificial neural network based models. Independent models were developed for estimating weld bead width and depth of penetration respectively. There was good correlation between the measured and estimated values of bead width and depth of penetration using the developed models.

Detailed analysis of the progressive accumulation of creep strain and cavitation across the joints were carried out on performing interrupted creep tests on joint specimens fabricated by single-pass activated TIG (A-TIG) and multi-pass TIG (MP-TIG) welding processes having grid marking inscribed on them before creep test. The localized creep deformation rate in the weld metal was faster in the MP-TIG joint than in the A-TIG joint. Creep cavitation was more pronounced in the MP-TIG joint. The different deformation and cavitation responses of the joints have been attributed to δ-ferrite contents and higher strength disparity within the weld metal.

Chelerythrine (CHL), a plant alkaloid, possesses antimicrobial, anti-inflammatory, and antitumor properties. Although CHL influences several key signal transduction pathways, its ability to interact directly with nucleoprotein complex chromatin, in eukaryotic cells has so far not been looked into. Here we have demonstrated its association with hierarchically assembled chromatin components, viz. long chromatin, chromatosome, nucleosome, chromosomal DNA, and histone H3 and the consequent effect on chromatin structure. CHL was found to repress acetylation at H3K9. It is more target-specific in terms of gene expression alteration and less cytotoxic compared to its structural analog sanguinarine.

Vascular development involvesde novoformation of a capillary plexus, which is then pruned and remodeled by angiogenic events. Cytoskeletal remodeling and directional endothelial migration are essential for developmental and pathological angiogenesis. Smad-dependent TGFβ signaling controls vascular patterning and is negatively regulated by microtubules. Here we show that a positive regulator of TGFβ signaling is essential for developmental vascular patterning and microtubule stability. Rudhira/BCAS3 is known to bind microtubules and to play a nodal role in cytoskeletal remodeling and directional endothelial cell (EC) migration invitro. We demonstrate that the molecular and cellular function of Rudhira is deployed at critical steps in vascular patterning. We generated the first floxed mice forrudhiraand find that global or endothelial knockout ofrudhiraresults in mid-gestation lethality due to aberrant embryonic and extra-embryonic vessel patterning and defective cardiac morphogenesis.Rudhiranull yolk sac ECs show random and retarded migration. Yolk sac transcriptome analysis revealed key mediators of angiogenic processes and TGFβ receptor signaling were perturbed inrudhiranull mutants. Molecular and biochemical analyses showed thatrudhiradepletion reduced microtubule stability but increased expression of pathway inhibitors leading to high levels of SMAD2/3 ubiquitination and reduced activation. These effects were not rescued by exogenous TGFβ. However, TGFβ treatment of wild type ECs increased Rudhira expression. Further, exogenous Rudhira, which promotes directional cell migration, caused increased SMAD2/3 nuclear translocation and reduced inhibitor levels. Therefore, we propose that Rudhira and TGFβ signaling are mutually dependent. Rudhira has a dual function in promoting TGFβ signaling, possibly by sequestering microtubules and simultaneously preventing SMAD2/3 ubiquitination to permit EC migration and vascular patterning. TGFβ signaling and aberrant human Rudhira (Breast Cancer Amplified Sequence 3, BCAS3) expression are both associated with tumour metastasis. Our study identifies a cytoskeletal, cell type-specific modulator of TGFβ signaling important in development and cancer.

Alveolar rhabdomyosarcoma (ARMS) is an aggressive paediatric cancer of skeletal muscle with poor prognosis. A PAX3-FOXO1 fusion protein acts as a driver of malignancy in ARMS by disrupting tightly coupled but mutually exclusive pathways of proliferation and differentiation. While PAX3-FOXO1 is an attractive therapeutic target, no current treatments are designed to block its oncogenic activity. The present work shows that the histone acetyltransferase P/CAF (KAT2B) is overexpressed in primary tumours from ARMS patients. Interestingly, in fusion-positive ARMS cell lines, P/CAF acetylates and stabilizes PAX3-FOXO1 rather than MyoD, a master regulator of muscle differentiation. Silencing P/CAF, or pharmacological inhibition of its acetyltransferase activity, down-regulates PAX3-FOXO1 levels concomitant with reduced proliferation and tumour burden in xenograft mouse models. Our studies identify a P/CAF-PAX3-FOXO1 signalling node that promotes oncogenesis and may contribute to MyoD dysfunction in ARMS. This work exemplifies the therapeutic potential of targeting chromatin-modifying enzymes to inhibit fusion oncoproteins that are a frequent event in sarcomas. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John WileySons, Ltd.

Welding introduces significant residual stresses in the welded structure/component due to non-uniform heat distribution during heating and cooling cycle. To control, reduce, or beneficially redistribute the residual stresses in weld joints, the stress distribution needs to be known. In the present study, weld joints of 10 mm thick 316LN stainless steel were made by multi-pass TIG and A-TIG welding processes and their residual stresses distribution and distortion values were measured and compared. While V-groove edge preparation was required for making multi-pass TIG weld joint, square-edge preparation was sufficient for making single pass A-TIG weld joint. Ultrasonic nondestructive technique based on the critically refracted longitudinal waves (LCR waves) has been used for the quantitative surface/sub-surface residual stress measurements in the weld joints. Distortion measurements were carried out before and after welding using height gauge. Peak tensile residual stress and the angular distortion values w...

Reduced-activated ferritic-martensitic steels are considered to be the prime candidate for structural material of the fusion power plant reactor design. Tungsten inert gas (TIG) welding is preferred for welding of those structural materials. However, the depth of penetration achievable during autogenous TIG welding is very limited and hence productivity is poor. Therefore, activated-flux tungsten inert gas (A-TIG) welding, a new variant of TIG welding process has been developed in-house to increase the depth of penetration in single pass welding. In structural materials produced by A-TIG welding process, weld bead width, depth of penetration and HAZ width decide the mechanical properties and in turn the performance of the weld joints during service. To obtain the desired weld bead geometry, HAZ width and make a reliable quality weld, it becomes important to develop predictive tools using soft computing techniques. In this work, adaptive neuro fuzzy inference system is used to develop independent models correlating the welding parameters like current, voltage and torch speed with bead shape parameters like weld bead width, depth of penetration, and HAZ width. During ANFIS modeling, various membership functions were used. Triangular membership function provided the minimum RMS error for prediction and hence, ANFIS model with triangular membership functions were chosen for predicting for weld bead shape parameters as a function of welding process parameters.

Tungsten inert gas (TIG) welding process is generally used to produce high quality weld joints of 9Cr-1Mo steel. However, there is limitation associated with the depth of penetration achievable in single pass autogenous welding. Specific activated flux has been developed in the present work to enhance the depth of penetration up to 6 mm in single pass by A-TIG welding. 9Cr-1Mo steel A-TIG weld joint using activated flux was made in single pass welding while the multipass TIG weld joint using modified 9Cr-1Mo filler wire was made in seven passes. The enhancement in depth of penetration during A-TIG welding process for this steel was attributed to arc constriction. The strength properties of the A-TIG weld joint was superior to that of the multipass TIG weld joint. The multipass TIG weld joint exhibited slightly improved impact toughness than the A-TIG weld joint in PWHT condition. Therefore, there was no degradation in the microstructure and mechanical properties of the weld joint produced by A-TIG welding...

Type 316 LN stainless steel is the major structural material used in the construction of nuclear reactors. Activated flux tungsten inert gas (A-TIG) welding has been developed to increase the depth of penetration because the depth of penetration achievable in single-pass TIG welding is limited. Real-time monitoring and control of weld processes is gaining importance because of the requirement of remoter welding process technologies. Hence, it is essential to develop computational methodologies based on an adaptive neuro fuzzy inference system (ANFIS) or artificial neural network (ANN) for predicting and controlling the depth of penetration and weld bead width during A-TIG welding of type 316 LN stainless steel. In the current work, A-TIG welding experiments have been carried out on 6-mm-thick plates of 316 LN stainless steel by varying the welding current. During welding, infrared (IR) thermal images of the weld pool have been acquired in real time, and the features have been extracted from the IR thermal images of the weld pool. The welding current values, along with the extracted features such as length, width of the hot spot, thermal area determined from the Gaussian fit, and thermal bead width computed from the first derivative curve were used as inputs, whereas the measured depth of penetration and weld bead width were used as output of the respective models. Accurate ANFIS models have been developed for predicting the depth of penetration and the weld bead width during TIG welding of 6-mm-thick 316 LN stainless steel plates. A good correlation between the measured and predicted values of weld bead width and depth of penetration were observed in the developed models. The performance of the ANFIS models are compared with that of the ANN models.

A novel variant of tungsten inert gas (TIG) welding called activated-TIG (A-TIG) welding, which uses a thin layer of activated flux coating applied on the joint area prior to welding, is known to enhance the depth of penetration during autogenous TIG welding and overcomes the limitation associated with TIG welding of modified 9Cr-1Mo steels. Therefore, it is necessary to develop a specific activated flux for enhancing the depth of penetration during autogeneous TIG welding of modified 9Cr-1Mo steel. In the current work, activated flux composition is optimized to achieve 6 mm depth of penetration in single-pass TIG welding at minimum heat input possible. Then square butt weld joints are made for 6-mm-thick and 10-mm-thick plates using the optimized flux. The effect of flux on the microstructure, mechanical properties, and residual stresses of the A-TIG weld joint is studied by comparing it with that of the weld joints made by conventional multipass TIG welding process using matching filler wire. Welded microstructure in the A-TIG weld joint is coarser because of the higher peak temperature in A-TIG welding process compared with that of multipass TIG weld joint made by a conventional TIG welding process. Transverse strength properties of the modified 9Cr-1Mo steel weld produced by A-TIG welding exceeded the minimum specified strength values of the base materials. The average toughness values of A-TIG weld joints are lower compared with that of the base metal and multipass weld joints due to the presence of δ-ferrite and inclusions in the weld metal caused by the flux. Compressive residual stresses are observed in the fusion zone of A-TIG weld joint, whereas tensile residual stresses are observed in the multipass TIG weld joint.

Creep rupture behaviour of type 316L(N) austenitic stainless steel base metal and its weld joints fabricated both by single-pass activated TIG (A-TIG) and multi-pass conventional TIG (MP-TIG) welding processes were studied at 923 K over a stress range of 160–280 MPa. Both the weld joints possessed lower creep rupture lives than the base metal. The A-TIG weld joint displayed higher rupture lives than the MP-TIG weld joint. Failure in the weld joints occurred in the weld metal. Progressive localization of creep deformation in the weld metal of both the joints led to the premature failure. Accumulation of creep deformation at higher rate was observed in the weld metal of the MP-TIG joint than in the A-TIG joint. Finer microstructural features and higher amount of δ-ferrite was observed in the weld metal of MP-TIG joint than in the A-TIG weld joint. Orientation of the columnar grains and δ-ferrite was nearly transverse to the welding direction in the A-TIG joint, whereas it was towards short transverse to the welding direction in the MP-TIG weld joint. TEM investigation of creep exposed weld metal showed the extensive formation of M 23 C 6 carbides, σ-phase and Laves phase along the boundaries in MP-TIG joint, which were less prevalent in the A-TIG joint. With creep exposure, the δ-ferrite transformed to σ and Laves phases, and creep cavitation was found to be associated with the intermetallic phases. Creep cavitation was more pronounced in the MP-TIG weld joint than in the A-TIG weld joint.

Real-time monitoring of the weld pool using infra-red (IR) thermography during gas tungsten arc (GTA) welding is gaining importance due to the requirements for on-line monitoring and control of the welding process. To facilitate real-time monitoring of the weld pool, a computer-controlled GTA welding machine with sensing of the weld pool using IR camera has been developed. The IR camera, mounted on the torch assembly, monitors the molten pool and the surface temperature distribution surrounding the weld pool during GTA welding. Temperature profiles were measured on the plates using thermocouples in combination with IR thermography to determine the emissivity of the plate surface. GTA welding was carried out on 3 mm-thick 316LN stainless steel (SS) plates under different welding conditions. IR thermal images were acquired on-line and analysed. A linear relationship was obtained between the thermal bead width, determined by line-scan analysis technique, and the actual bead width, measured by cross-sectional optical microscopy. The computed macroscopic temperature gradient and the actual of weld bead depth of penetration showed an inverse relationship. Full-frame analysis was carried out to estimate the surface temperature distribution for square-butt weld joints. For 1316LN SS weld joints, IR thermal signatures were acquired for various weld defects, such as lack of fusion, lack of penetration and tungsten inclusions, for use as reference signatures for on-line monitoring during GTA welding.

316L(N) stainless steel plates were joined using activated-tungsten inert gas (A-TIG) welding and conventional TIG welding process. Creep rupture behavior of 316L(N) base metal, and weld joints made by A-TIG and conventional TIG welding process were investigated at 923 K over a stress range of 160–280 MPa. Creep test results showed that the enhancement in creep rupture strength of weld joint fabricated by A-TIG welding process over conventional TIG welding process. Both the weld joints fractured in the weld metal. Microstructural observation showed lower δ -ferrite content, alignment of columnar grain with δ -ferrite along applied stress direction and less strength disparity between columnar and equiaxed grains of weld metal in A-TIG joint than in MP-TIG joint. These had been attributed to initiate less creep cavitation in weld metal of A-TIG joint leading to improvement in creep rupture strength.

It is necessary to estimate the weld bead width and depth of penetration using suitable sensors during welding to monitor weld quality. Among the vision sensors, infra red sensing is the natural choice for monitoring welding processes as welding is inherently a thermal processing method. An attempt has been made to estimate the weld bead width and depth of penetration from the infra red thermal image of the weld pool using artificial neural network models during A-TIG welding of 3 mm thick type 316 LN stainless steel plates. Real time infra red images were captured using IR camera for the entire weld length during A-TIG welding at various current values. The image features such as length and width of the hot spot, peak temperature, and other features using line scan analysis are extracted using image processing techniques corresponding to particular locations of the weld joint. These parameters along with their respective current values are used as inputs while the measured weld bead width and depth of penetration are used as output of the neural network models. Accurate ANN models predicting weld bead width (9-11-1) and depth of penetration (9-9-1) have been developed. The correlation coefficient values obtained were 0.98862 and 0.99184 between the measured and predicted values of weld bead width and depth of penetration respectively.

Modified 9Cr-1Mo ferritic steel is used as a structural material for steam generator components of power plants. Generally, tungsten inert gas (TIG) welding is preferred for welding of these steels in which the depth of penetration achievable during autogenous welding is limited. Therefore, activated flux TIG (A-TIG) welding, a novel welding technique, has been developed in-house to increase the depth of penetration. In modified 9Cr-1Mo steel joints produced by the A-TIG welding process, weld bead width, depth of penetration, and heat-affected zone (HAZ) width play an important role in determining the mechanical properties as well as the performance of the weld joints during service. To obtain the desired weld bead geometry and HAZ width, it becomes important to set the welding process parameters. In this work, adaptative neuro fuzzy inference system is used to develop independent models correlating the welding process parameters like current, voltage, and torch speed with weld bead shape parameters like depth of penetration, bead width, and HAZ width. Then a genetic algorithm is employed to determine the optimum A-TIG welding process parameters to obtain the desired weld bead shape parameters and HAZ width.

An intelligent model combining artificial neural network (ANN) and genetic algorithm (GA) has been developed for determining the optimum process parameters for achieving the desired depth of penetration and weld bead width during Activated Flux Tungsten Inert Gas Welding (A-TIG) welding of type 316LN and 304LN stainless steels. First, ANN models correlating process parameters with depth of penetration and weld bead width have been developed. There was good correlation between the measured and models predicted depth of penetration as well as the weld bead width for both training and test data. A GA code was developed in MATLAB in which the objective function was evaluated using the ANN models. The optimized values for GA parameters such as crossover rate, population size, and mutation probability were identified. The developed GA model produced multiple outputs such as current, torch speed, voltage, and arc gap for the same target depth of penetration and bead width, and validation was carried out by exper...

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In the present study, thermo-mechanical behavior of 316LN stainless steel thin plates during activated tungsten inert gas (A-TIG) welding was investigated using SYSWELD®. A-TIG welding was carried out with more reduced heat input for fabricating 3-mm-thick 316LN stainless steel plates than that of the conventional TIG welding process. Induced transient temperature during welding was measured using a K-type thermocouple. A pulse-echo ultrasonic test was carried out using a 2-MHz probe employing critically refracted longitudinal waves for measuring residual stresses across the weld joint. A digital height gauge was used to quantify the distortion caused during welding. There was a good agreement between the predicted and measured thermal cycles, residual stresses, and distortion. The concentrated heat intensity of A-TIG welding induced higher surface temperature in the weld center, produced a narrow weld bead, and exhibited a sharp temperature gradient at the weld/base metal interface. Peak residual stress and distortion of the A-TIG weld joint were found to be less than that of the TIG weld joint.