Search

In this investigation, the optimization of mechanical properties with thermal post-processing treatments was analyzed across a wide range of variants. A major aspect of additive manufacturing is the correlation between heat treatments and the effects on the mechanical properties and microstructure of the printed materials. Therefore, the present paper describes a comprehensive overview of post-process heat treatments for Laser Powder Bed Fusion fabricated AlSi10Mg alloy consisting of stress relief anneals at 190 C and 285 C for 2 h, hot isostatic pressing at 515 C for 3 h, hot isostatic pressing + T6 treatment for 6 h, and final aging of each of these conditions at 177 C for up to 1000 h. This has resulted in 40 experimental variants: 20 in the vertical and 20 in the horizontal tensile direction. After tensile testing, the resulting mechanical properties (ultimate tensile strength, yield strength, and elongation) and stress–strain curves are analyzed for comparison between all variants. Ultra-fine cellular, micro dendritic structures (0.6–1.2 μm) along with melt-band structures dominated the asbuilt and stress relief anneal conditions. In contrast, hot isostatic pressing and hot isostatic pressing + T6 conditions were dominated by ~10 μm, equiaxed, recrystallized grain structures and pseudo-eutectic silicon particles with varying sizes and size distributions. Microhardness and fractography results also corresponded to their specific heat treatment and microstructure. The comparison and correlation of the heat treatments are presented to help advance the selection of design strategies for high performance applications.

The macrotrabecular (MT) pattern of hepatocellular carcinoma (HCC) has been suggested to represent a distinct HCC subtype. We retrospectively reviewed 231 HCC cases. Detailed pathologic evaluation for histologic patterns, including MT-pattern, was performed for each case and recorded as percentage involved at 10% intervals. MT-pattern was defined as having trabeculae6 cells thick. After excluding all recognized HCC subtypes, remaining cases were deemed conventional HCC (CV-HCC) and served as controls. HCCs with a component of ≥10%, ≥30% and ≥50% MT-pattern were identified in 41 (17.7%), 24 (10.4%) and 4 (1.7%) cases, respectively. The clinicopathologic features of HCCs with 10% to 29% MT-pattern (n=17, 7.4%) were largely similar to CV-HCC. No significant difference was observed between the 30% and 49% (n=20) and ≥50% (n=4) MT groups, hence these were combined for further analysis as MT-HCC. MT-HCCs (≥30% MT-pattern) were larger tumors (5.5 vs. 3.1 cm), were less likely to be associated with cirrhosis (54% vs. 79%), were more likely to have hepatitis B (21% vs. 5%) and less likely hepatitis C infection (33% vs. 58%) compared with CV-HCC. MT-HCC was associated with the presence of anaplastic tumor cells (42% vs. 14%), higher alpha-fetoprotein level, higher AJCC stage, and higher histologic grade. Compared with patients with CV-HCC, patients with MT-HCC had poorer overall survival. Patients with MT-HCC who underwent primary resection or transplantation had a higher recurrence rate and worse recurrence-free survival. Our findings suggest that ≥30% MT-pattern could be used as the more appropriate cut-off for defining MT-HCC, which represents a unique and aggressive HCC histologic subtype.

Calcifying nested stromal-epithelial tumor is a rare entity that has gone by a variety of names in the literature: ossifying malignant mixed epithelial and stromal tumor, ossifying stromal-epithelial tumor, and desmoplastic nested spindle cell tumor of the liver. To our knowledge, approximately 38 cases have been reported in the literature. The histogenesis is still largely unknown but histopathologically is characterized by nests of spindle and epithelioid cells in an organoid arrangement surrounded by a prominent dense myofibroblastic stroma with occasional psammomatous calcification and focal heterotopic ossification. Vascular invasion is rare and tumoral recurrence is uncommon with only a single reported case of metastasis leading to death. Treatment is mainly by surgical intervention with the role of chemotherapy seeming limited, but lack of data hinders a true recommendation. It is important to rule out other processes such as hepatoblastoma, calcified hemangioma, synovial sarcoma, metastatic gastrointestinal stromal tumor, desmoplastic small round cell tumor, among others, which appear similar radiographically and histopathologically.

Objectives Gastric adenocarcinoma of the fundic gland type (GA-FG) is a newly described entity with a lack of awareness amongst general surgical pathologists and this review highlights the key features and controversies associated with this uncommon neoplasm. Methods A literature search through PubMed using synonyms for GA-FG was conducted to obtain 111 cases. Results GA-FG is a well-differentiated neoplasm of oxyntic mucosa, that is comprised of chief cells and parietal cells. Chief cell differentiation is highlighted with Muc-6, RUNX3, and pepsinogen. Parietal cells are highlighted with H+/K+ ATPase and PDGFRA-α. Association with Helicobacter infection, chronic gastritis, intestinal metaplasia, or gastric atrophy is not seen. Most GA-FGs are confined to the mucosa. Deeper invasion, lymphovascular invasion, nodal metastasis, and extragastric spread are uncommon. Conclusions GA-FGs are rare lesions that typically follow a benign course. However, despite features of malignancy in some cases, complete surgical excision, sometimes with endoscopic mucosal resection, seems adequate treatment.

Abernethy malformation, also termed congenital portosystemic shunt and congenital absence of portal vein is the result of malformation of the splanchnic venous system. Congenital portosystemic shunts are divided into extra- and intrahepatic shunts. Two shunts have been defined: Type I is characterized by the complete diversion of portal blood into the vena cava with an associated congenital absence of the portal vein. Type II is defined by an intact but diverted portal vein through a side-to-side, extrahepatic connection to the vena cava. The clinical manifestations of Abernethy malformation are diverse with a typical presentation consisting of hypoxia and hepto-pulmonary syndrome. Histologically, focal nodular hyperplasia, nodular regenerative hyperplasia, liver adenoma, hepatoblastoma, and hepatocellular carcinoma have all been reported. Herein, we report a case of Abernethy malformation, type Ib, in a 12-month-old male who was found to have a small hepatocellular carcinoma at the time of explant. The immunohistochemical characteristics in relation to the genetic aspects are discussed. To our knowledge, this is the first reported case of hepatocellular carcinoma developing in a patient who is under the age of 5 years with Abernethy malformation.

Papillary thyroid carcinoma is a common malignancy to affect the thyroid and is typified by a nonaggressive nature and low rates of mortality. In contrast, anaplastic thyroid carcinoma is the most aggressive thyroid malignancy with a mortality rate of nearly 90% and survival typically of only six months after the diagnosis is made. The transformation of papillary thyroid carcinoma to anaplastic thyroid carcinoma is well documented in the literature but is uncommon and in most instances is reported as a case report or small series only. Transformation of papillary thyroid carcinoma to anaplastic thyroid carcinoma usually takes place in the thyroid itself or in the adjacent lymph nodes. Only on rare occasions does a transformation occur in a papillary thyroid carcinoma metastasis outside of these locations. In the present case report and subsequent discussion we highlight an unusual case of PTC with transformation to anaplastic thyroid carcinoma, which is shown to involve numerous locations to include near total lung parenchyma obliteration. We also discuss the differential diagnostic challenges when faced with a thyroid malignancy that is negative for thyroglobulin.

We describe a novel physical application of the OctTree data structure [P. Meagher, Comput. Graphics Image Process 19(2) (1982) 129–147] in a dynamically tessellating algorithm, in conjunction with an object-oriented, constructive solid geometry library (DOC), to efficiently determine pore size distributions in large multi-particle systems. We apply the DOC library to investigate the evolving dynamics of pore formation in multi-particle systems, such as a mixture of smooth hard cubes and spheres and a collection of frictional soft spheres. We demonstrate that the algorithm is able to provide insight into the effect of structural changes on the porosity network; for example, during the uniaxial compaction of soft spheres, we find the number density of pores increases while the mean volume of the pores decreases. This trend is responsible for a shift in the distribution of the pore volumes to favour smaller volumes. We anticipate that the DOC method will have wider applications in the area of granular materials for studying the changes in pore structure in both experimental and numerical systems as a complement to the analysis of particle packing.

[Figure][1] An asymptomatic 66-year-old woman presented with an elevated total protein of 9.1 g on routine blood work. Serum protein electrophoresis showed an immunoglobulin A (IgA) κ (kappa) M-spike measuring 3570 mg/dL with depression of immunoglobulins M and G (IgM and IgG). Renal

Colorectal carcinoma (CRC), as the third most common new cancer diagnosis, poses a significant health risk to the population. Interval CRCs are those that appear after a negative screening test or examination. The development of interval CRCs has been shown to be multifactorial: location of exam-academic institution versus community hospital, experience of the endoscopist, quality of the procedure, age of the patient, flat versus polypoid neoplasia, genetics, hereditary gastrointestinal neoplasia, and most significantly missed or incompletely excised lesions. The rate of interval CRCs has decreased in the last decade, which has been ascribed to an increased understanding of interval disease and technological advances in the screening of high risk individuals. In this article, we aim to review the literature with regard to the multifactorial nature of interval CRCs and provide the most recent developments regarding this important gastrointestinal entity.

Electron beam melting (EBM) additive manufacturing (AM) technology has allowed the layerwise fabrication of parts from metal powder precursor materials that are selectively melted using an electron beam. An advantage of EBM technology over conventional manufacturing processes has been the capability to change processing variables (e.g., beam current, beam speed, and beam focus) throughout part fabrication, enabling the processing of a wide variety of materials. In this research, additional scans were implemented in an attempt to promote grain coarsening through the added thermal energy. It is hypothesized that the additional energy caused coarsening of Ti-6Al-4V microstructure that has been shown to increase mechanical properties of as-fabricated parts as well as improve surface characteristics (e.g., reduced porosity). Fatigue testing was performed on an L-bracket using a loading configuration designed to cause failure at the corner (i.e., intersection of the two members) of the bracket. Results showed 22% fatigue life improvement from L-brackets with as-fabricated conditions to L-brackets with a graded microstructure resulting from the selective addition of thermal energy in the expected failure region. Three L-brackets were fabricated and exposed to a triple melt cycle (compared to the standard single melt cycle) during fabrication, machined to specific dimensions, and tested. Results for fatigue performance were within ∼1% of wrought L-brackets. The work from this research shows that new design procedures can be implemented for AM technologies that involve evaluation of stress concentration sites using finite element analysis and implementation of scanning strategies during fabrication that help improve performance by spatially adjusting thermal energy at potential failure sites or high stress regions.

The molecular dynamics package DL_POLY has at its heart a number of versatile and efficient dynamics algorithms that can readily be adapted to extend the application of this code well beyond the time and length scales typically associated with atomistic simulations. In order to achieve this, it is necessary to substitute the appropriate interparticle potentials and forces in place of the default functional forms in DL_POLY, which are mainly suitable for molecular systems. To facilitate this, it may be required to incorporate additional factors, into the simulation, such as velocity-dependent dissipation effects (friction), rotational degrees of freedom and non-spherosymmetric forces. In this paper, we will discuss some of the practical details of implementing these changes to DL_POLY (version 2) together with applications of discrete particle dynamics methods, such as dissipative particle dynamics (DPD) and granular dynamics (GD) (also known as the discrete or distinct element method, DEM) to particle pac...

Eccrine spiradenomas are uncommon, benign lesions, which are thought to originate from the eccrine sweat glands. They are common in young adults and are without a sex predilection. Here we report a case of eccrine spiradenoma of the breast skin in a 39-year-old woman who presented with a breast nodule for 10 years. It is crucial to take eccrine spiradenoma into consideration in superficial, well-circumscribed, breast skin/subcutaneous lesions. It is useful to recognize the two-cell populations constituting this tumor: small, dark, basaloid cells with hyperchromatic nuclei, which are immunoreactive for P63 and calponin, and larger cells with a pale nucleus, often near the center of the cluster (inner cells), which are immunoreactive for CK7 and CD117 (C-kit).

High-precision timing is an exciting field of pulsar research that holds the promise of direct gravitational wave detection. This goal is at the limit of current technology, and requires the near-seamless combination of data from multiple pulsars observed with multiple telescopes. Accuracy in the recording of pulse profiles and the measurement of their times of arrival (TOAs) is key. In order to time a pulsar, a template is needed that is as close as possible to an ideal version of the pulse profile. Four pulsars were timed using analytic, noise-free templates composed of Gaussian components, and their system parameters were measured to high accuracy. These templates were found to be usable at different telescopes and were adaptable across more than 100 MHz in observing frequency without loss of TOA alignment.The same approach was used to investigate profile variation in the pulsar PSR J1022+1001, which is a promising member of the arrays used to search for gravitational waves. Variation with time was found that is almost equal in magnitude to typical measurement noise. The timing of the pulsar could not be improved using adaptive templates which were allowed to vary with the profile to a limited extent. If the variation is due to instrumental error, then its removal would improve timing accuracy significantly for this pulsar. If it is intrinsic, then it is an interesting and unusual phenomenon. PSRJ1022+1001 was compared to two similar pulsars, one of which showed a lesser degree of variation and one of which did not exhibit significant change.Timing of PSR J1022+1001 was used to calculate upper limits on the amplitude of the stochastic gravitational wave background. A reasonable limit was estimated to be Amax = 1.7 x 10^-14, which is stringent for a single pulsar timed alone. However, there was evidence that the timing residuals were somewhat correlated in time, which can produce an artificially low limit. Nevertheless, PSR J1022+1001 has the potential to make a valuable contribution to gravitational wave detection. Investigation into its variation highlights the fact that the timing of a number of pulsars may be crucially improved by the next generation of processing instruments.

Effective vector control, and more specifically mosquito control, is a complex and difficult problem, as illustrated by the continuing prevalence (and spread) of mosquito-transmitted diseases. The sterile insect technique and similar methods control certain agricultural insect pest populations in a species-specific, environmentally sound, and effective manner; there is increased interest in applying this approach to vector control. Such an approach, like all others in use and development, is not a one-size-fits-all solution, and will be more appropriate in some situations than others. In addition, the proposed release of pest insects, and more so genetically modified pest insects, is bound to raise questions in the general public and the scientific community as to such a method's efficacy, safety, and sustainability. This article attempts to address these concerns and indicate where sterile-insect methods are likely to be useful for vector control.

It is widely accepted that hyperglycemia per se incites and perpetuates the diabetic state be adverse effects on β cell insulin secretion and peripheral insulin action. Examination of the latter locus has revealed glucose-related abnormalities in facilitated glucose transport. Beyond the plasma membrane, however, there is scant data examining whether hyperglycemia influences important intracellular metabolic events. We recently described a sizable reduction in post-transport, in situ metabolism in permeabilized fat cells from streptozocin-induced diabetic rats. Of importance, the diabetes-related deficit was entirely ameliorated by insulin therapy. In this study we examined whether hyperglycemia per se contributes to this altered intracellular metabolic effect. By infusing phlorizin, near euglycemia was achieved for at least four days in streptozocin-induced diabetic rats. The phlorizin-treated diabetic rats had improved (intact cell) rates of insulin-stimulated 2-deoxyglucose uptake. Despite this, permeabilized fat cell studies revealed non improvement or deterioration in diabetic intracellular metabolism as measured by both the oxidation of [6- 14 C]glucose-6-phosphate via the citric acid cycle or its incorporation into triglyceride. We conclude that hypoinsulinemia, and not hyperglycemia, mediates the disturbance in porous diabetic adipocyte cellular metabolism.

Carrier sense multiple access (CSMA) protocols were originally conceived for use in digital radio communication. Such protocols are, however, quite applicable in a variety of distributed computing and local networking configurations based on a shared bus. The CSMA protocols are characterized by the fact that message collisions can occur only in a very small time window whose duration corresponds to the propagation delay of the bus. They are further characterized by the technique used to subsequently serialize the transmission of the colliding messages. In this paper we analyze the situation wherein colliding messages are serialized by using a set of staggered `retry' delays which are associated with the sources that may generate the colliding messages. Our analysis produces both path throughput (utilization) curves and message delay curves, as a function of message generation rate. These curves show that the protocol is in a sense self stabalizing, serve to quantify its behaviour, and indicate loading levels which result in unacceptable message delays.