An experimental investigation on the machining characteristics of Nimonic 75 using uncoated and TiAlN coated tungsten carbide micro-end mills

We report the machining characteristics and machinability of a nickel based superalloy in this study. A micro-milling operation is loaded on Nimonic 75 using uncoated and TiAlN coated tungsten carbide micro-end mills. A full factorial design of experiments was devised to optimize the machining conditions to reduce the flank wear on the tool surface. The optimized machining conditions for uncoated micro-tools were found to be a cutting speed (vc) of 13 m/min and a feed rate (fz) of 6 mm/min. Following this, the tools were coated with TiAlN using a semi-industrial four-cathode reactive pulsed direct current unbalanced magnetron sputtering system. Further experiments were then performed using these optimized machining conditions using both uncoated and TiAlN coated micro-tools in order to ascertain the tool wear and surface integrity. The change in geometry of the machined slot was estimated based on the variation in tool radius of the micro-end mill with progression of the operation. A direct comparison was made between the results observed using both uncoated and TiAlN coated tungsten carbide to illustrate the effect of the nanocomposite TiAlN coating. It was seen that TiAlN coated micro-tools exhibited a superior performance as compared to the uncoated ones with respect to tool life and micro-burr formation

Reporting trends, practices, and resource utilization in neuroendocrine tumors of the prostate gland: a survey among thirty-nine genitourinary pathologists

Background: Neuroendocrine differentiation in the prostate gland ranges from clinically insignificant neuroendocrine differentiation detected with markers in an otherwise conventional prostatic adenocarcinoma to a lethal high-grade small/large cell neuroendocrine carcinoma. The concept of neuroendocrine differentiation in prostatic adenocarcinoma has gained considerable importance due to its prognostic and therapeutic ramifications and pathologists play a pivotal role in its recognition. However, its awareness, reporting, and resource utilization practice patterns among pathologists are largely unknown. Methods: Representative examples of different spectrums of neuroendocrine differentiation along with a detailed questionnaire were shared among 39 urologic pathologists using the survey monkey software. Participants were specifically questioned about the use and awareness of the 2016 WHO classification of neuroendocrine tumors of the prostate, understanding of the clinical significance of each entity, and use of different immunohistochemical (IHC) markers. De-identified respondent data were analyzed. Results: A vast majority (90%) of the participants utilize IHC markers to confirm the diagnosis of small cell neuroendocrine carcinoma. A majority (87%) of the respondents were in agreement regarding the utilization of type of IHC markers for small cell neuroendocrine carcinoma for which 85% of the pathologists agreed that determination of the site of origin of a high-grade neuroendocrine carcinoma is not critical, as these are treated similarly. In the setting of mixed carcinomas, 62% of respondents indicated that they provide quantification and grading of the acinar component. There were varied responses regarding the prognostic implication of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and for Paneth cell-like differentiation. The classification of large cell neuroendocrine carcinoma was highly varied, with only 38% agreement in the illustrated case. Finally, despite the recommendation not to perform neuroendocrine markers in the absence of morphologic evidence of neuroendocrine differentiation, 62% would routinely utilize IHC in the work-up of a Gleason score 5 + 5 = 10 acinar adenocarcinoma and its differentiation from high-grade neuroendocrine carcinoma. Conclusion: There is a disparity in the practice utilization patterns among the urologic pathologists with regard to diagnosing high-grade neuroendocrine carcinoma and in understanding the clinical significance of focal neuroendocrine cells in an otherwise conventional acinar adenocarcinoma and Paneth cell-like neuroendocrine differentiation. There seems to have a trend towards overutilization of IHC to determine neuroendocrine differentiation in the absence of neuroendocrine features on morphology. The survey results suggest a need for further refinement and development of standardized guidelines for the classification and reporting of neuroendocrine differentiation in the prostate gland

The Evolving Concepts of Cancer Stem Cells in Head and Neck Squamous Cell Carcinoma

There is increasing evidence that the growth and spread of cancers is driven by a small subpopulation of cancer stem cells (CSCs)-the only cells that are capable of long-term self-renewal and generation of the phenotypically diverse tumor cell population. CSCs have been identified and isolated in a variety of human cancers including head and neck squamous cell carcinoma (HNSCC). The concept of cancer stem cells may have profound implications for our understanding of tumor biology and for the design of novel treatments targeted toward these cells. The present review is an attempt to conceptualize the role of CSCs in HNSCC-its implication in tumorigenesis and the possible additional approach in current treatment strategies

The Evolving Concepts of Cancer Stem Cells in Head and Neck Squamous Cell Carcinoma

There is increasing evidence that the growth and spread of cancers is driven by a small subpopulation of cancer stem cells (CSCs)—the only cells that are capable of long-term self-renewal and generation of the phenotypically diverse tumor cell population. CSCs have been identified and isolated in a variety of human cancers including head and neck squamous cell carcinoma (HNSCC). The concept of cancer stem cells may have profound implications for our understanding of tumor biology and for the design of novel treatments targeted toward these cells. The present review is an attempt to conceptualize the role of CSCs in HNSCC—its implication in tumorigenesis and the possible additional approach in current treatment strategies

Review on the machining characteristics and research prospects of conventional micro-scale machining operations

The concept of miniaturizing machine tools has received a strong interest in the research community due to their ability to fabricate intricate components. Lower power consumption, higher productivity rate and smaller sizes of work stations have enabled micro-scale machining operations to acquire an edge over other fabrication techniques in various applications such as aerospace, instrumentation, automotive, biomedical, etc. The literature is filled with works done by researchers working in this domain. A significant contribution comes from the works which have been published during the period 1998-2014. The focus of these studies has primarily been on conventional and non-conventional micro-machining techniques. Since non-conventional machining operations such as micro-electrical discharge machining, laser machining, etc. are not compatible with traditional workpiece materials, conventional micro-machining techniques such as micro-milling and micro-drilling are generally used. However, as of today, there has been no revision on the state-of-the-art in this field to serve as a reference for the experienced researcher and as a handbook for the newcomer. In this review, we have attempted to summarize the current state of understanding on this topic. A variety of issues which are representative of micro-machining operations are critically analyzed and presented. Conventional micro-machining operations have been compared with their non-conventional counterparts with respect to performance characteristics such as burr formation, surface integrity, etc. and their advantages and shortcomings have been listed. Meticulous efforts have been taken to address the key challenges faced in typical micro-machining operations. Taking the convenience of the reader into consideration, we have presented a bird's-eye view of the various micro-machining operations and simulation studies as performed in the last decade. In the last few years, diamond turning operations have gained more importance and are particularly used for machining composite materials and superalloys. This paper gives an insight into these operations apart from providing an outlook for future growth and development of micro-machining technology

Influence of machining conditions on tool wear, hole diameter accuracy and surface roughness in the micro-drilling of Nimonic 80A superalloy using uncoated and TiAlN coated micro-drills

Superalloys such as Nimonic 80A have high strength at elevated temperatures, which make them attractive towards various applications in aerospace industry

Development of transparent and conducting indium tin oxide (ITO) thin films by reactive sputtering at low substrate temperature

Transparent and conducting indium tin oxide (ITO) thin films were deposited on different substrates such as: glass, fluorinated ethylene propylene, Si, Kapton and aluminized Kapton by reactive sputtering at low substrate temperature. The effects of different deposition parameters such as target power, oxygen and argon flow rates, substrate temperature and deposition duration on the optical and electrical properties of ITO thin films have been studied. Optical and electrical properties of ITO thin films on different substrates were studied. The optimized ITO films were characterized using X-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy etc

Nanoindentation response of ITO film

We report nanoindentation response of indium tin oxide (ITO) film deposited by reactive direct current (DC) magnetron sputtering. The phase pure ITO film showed dense and needle-like nanostructure. Detailed mechanical characterization of ITO film was carried out by the nanoindentation technique. The average nanohardness and elastic modulus were evaluated as about 17.5 GPa and 189 GPa, respectively. Comparatively higher nanohardness and modulus values were found in the present work, which is possibly linked with the dense nanostructure of the ITO film. Further, fracture toughness was measured as ~0.56 MPa.m0.5. The corresponding projected area of indentation, elastic energy and plastic energy were also reported