Surface Defect incorporated Diamond Machining of Silicon

This paper reports the performance enhancement benefits in diamond turning of the silicon wafer by incorporation of the Surface Defect Machining (SDM) method. The hybrid micromachining methods usually require additional hardware to leverage the added advantage of hybrid technologies such as laser heating, cryogenic cooling, electric pulse or ultrasonic elliptical vibration. The SDM method tested in this paper does not require any such additional baggage and is easy to implement in a sequential micro-machining mode. This paper made use of Raman spectroscopy data, average surface roughness data and imaging data of the cutting chips of silicon for drawing a comparison between conventional Single Point Diamond Turning (SPDT) and SDM while incorporating surface defects in the (i) circumferential and (ii) radial directions. Complimentary 3D Finite Element Analysis (FEA) was performed to analyse the cutting forces and the evolution of residual stress on the machined wafer. It was found that the surface defects generated in the circumferential direction with an interspacing of 1 mm revealed the lowest average surface roughness (Ra) of 3.2 nm as opposed to 8 nm Ra obtained through conventional SPDT using the same cutting parameters. The observation of the Raman spectroscopy performed on the cutting chips showed remnants of phase transformation during the micromachining process in all cases. FEA was used to extract quantifiable information about the residual stress as well as the sub-surface integrity and it was discovered that the grooves made in the circumferential direction gave the best machining performance. The information being reported here is expected to provide an avalanche of opportunities in the SPDT area for low-cost machining solution for a range of other nominal hard, brittle materials such as SiC, ZnSe and GaAs as well as hard steels

IgA-dominant post-infectious glomerulonephritis presenting as a fatal pulmonary-renal syndrome

Over the last decades, post-infectious glomerulonephritis underwent major changes in its epidemiology, pathophysiology, and outcomes. We are reporting a case of IgA-dominant post-infectious glomerulonephritis (IgA-PIGN) presenting as a fatal pulmonary-renal syndrome. An 86-year-old Filipino man presented with worsening dyspnea, hemoptysis, and decreased urine output over 2 weeks. Past medical history is significant for hypertension, chronic kidney disease stage III, and pneumonia 3 weeks prior treated with intravenous cefazolin for methicillin-sensitive Staphylococcus aureus bacteremia. Physical examination was remarkable for heart rate of 109/min and respiratory rate of 25/min saturating 99% on 3 liters via nasal cannula. There were bibasilar rales in the lungs and bilateral ankle edema. A chest radiograph showed bibasilar opacifications. Blood work was significant for hemoglobin of 8.3 g/dL and creatinine of 9.2 mg/dL (baseline of 1.67). TTE showed EF 55%. Urinalysis revealed large blood and red blood cell casts. Kidney ultrasound showed bilateral echogenicity compatible with renal disease. Pulse methylprednisolone therapy and hemodialysis were initiated with patient\u27s condition precluding kidney biopsy. Serology workup for rapidly progressive glomerulonephritis was negative. On day 7, the patient required mechanical ventilation; bronchoscopy showed alveolar hemorrhage and plasmapheresis was initiated. Renal biopsy revealed IgA-PIGN with endocapillary and focal extracapillary proliferative and exudative features. IgA-PIGN occurs in diabetic elderly (mean age of 60 years), 0-16 weeks after an infection mainly by Staphylococcus. However, this nondiabetic patient had normal complement IgA-PIGN with fatal pulmonary-renal syndrome. Understanding the pathogenesis and identifying the nephrotoxic bacteria species and the aberrant IgA molecule will open new insights toward prevention and treatment

Testosterone deficiency increases hospital readmission and mortality rates in male patients with heart failure.

BackgroundTestosterone deficiency in patients with heart failure (HF) is associated with decreased exercise capacity and mortality; however, its impact on hospital readmission rate is uncertain. Furthermore, the relationship between testosterone deficiency and sympathetic activation is unknown.ObjectiveWe investigated the role of testosterone level on hospital readmission and mortality rates as well as sympathetic nerve activity in patients with HF.MethodsTotal testosterone (TT) and free testosterone (FT) were measured in 110 hospitalized male patients with a left ventricular ejection fraction < 45% and New York Heart Association classification IV. The patients were placed into low testosterone (LT; n = 66) and normal testosterone (NT; n = 44) groups. Hypogonadism was defined as TT < 300 ng/dL and FT < 131 pmol/L. Muscle sympathetic nerve activity (MSNA) was recorded by microneurography in a subpopulation of 27 patients.ResultsLength of hospital stay was longer in the LT group compared to in the NT group (37 ± 4 vs. 25 ± 4 days; p = 0.008). Similarly, the cumulative hazard of readmission within 1 year was greater in the LT group compared to in the NT group (44% vs. 22%, p = 0.001). In the single-predictor analysis, TT (hazard ratio [HR], 2.77; 95% confidence interval [CI], 1.58-4.85; p = 0.02) predicted hospital readmission within 90 days. In addition, TT (HR, 4.65; 95% CI, 2.67-8.10; p = 0.009) and readmission within 90 days (HR, 3.27; 95% CI, 1.23-8.69; p = 0.02) predicted increased mortality. Neurohumoral activation, as estimated by MSNA, was significantly higher in the LT group compared to in the NT group (65 ± 3 vs. 51 ± 4 bursts/100 heart beats; p < 0.001).ConclusionThese results support the concept that LT is an independent risk factor for hospital readmission within 90 days and increased mortality in patients with HF. Furthermore, increased MSNA was observed in patients with LT

Concomitant ipsilateral intracapsular and extracapsular femoral neck fracture: a case report

<p>Abstract</p> <p>Introduction</p> <p>Intracapsular and extracapsular hip fractures are common amongst elderly patients but simultaneous intracapsular and extracapsular hip fractures are rare.</p> <p>Case presentation</p> <p>We present the case of an elderly woman who sustained simultaneous intracapsular and extracapsular hip fractures and describe the complications which ensued following fixation.</p> <p>Conclusion</p> <p>Concomitant ipsilateral intracapsular and extracapsular femoral neck fracture is an uncommon injury pattern. It occurs most commonly in osteoporotic patients with low energy falls. Close examination of radiographs must be made to ensure that more subtle fractures are not overlooked and the injury managed appropriately. If doubt exists on initial radiographs further imaging should be considered.</p

Phosphatidylinositol-4,5 Bisphosphate Produced by PIP5K(gamma) Regulates Gelsolin, Actin Assembly, and Adhesion Strength of N-Cadherin Junctions

Phosphoinositides regulate several actin-binding proteins but their role at intercellular adhesions has not been defined. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) was generated at sites of N-cadherin–mediated intercellular adhesion and was a critical regulator of intercellular adhesion strength. Immunostaining for PI(4,5)P2 or transfection with GFP-PH-PLCδ showed that PI(4,5)P2 was enriched at sites of N-cadherin adhesions and this enrichment required activated Rac1. Isoform-specific immunostaining for type I phosphatidylinositol 4-phosphate 5 kinase (PIP5KI) showed that PIP5KIγ was spatially associated with N-cadherin–Fc beads. Association of PIP5KIγ with N-cadherin adhesions was in part dependent on the activation of RhoA. Transfection with catalytically inactive PIP5KIγ blocked the enrichment of PI(4,5)P2 around beads. Catalytically inactive PIP5KIγ or a cell-permeant peptide that mimics and competes for the PI(4,5)P2-binding region of the actin-binding protein gelsolin inhibited incorporation of actin monomers in response to N-cadherin ligation and reduced intercellular adhesion strength by more than twofold. Gelsolin null fibroblasts transfected with a gelsolin severing mutant containing an intact PI(4,5)P2 binding region, demonstrated intercellular adhesion strength similar to wild-type transfected controls. We conclude that PIP5KIγ-mediated generation of PI(4,5)P2 at sites of N-cadherin contacts regulates intercellular adhesion strength, an effect due in part to PI(4,5)P2-mediated regulation of gelsolin

Two-dimensional visibility charts for continuous curves

This paper considers computation of visibility for two-dimensional shapes whose boundaries are C1 continuous curves. We assume we are given a one-parameter family of candidate viewpoints, which may be interior or exterior to the object, and at finite or infinite locations. We consider how to compute whether the whole boundary of the shape is visible from some finite set of viewpoints taken from this family, and if so, how to compute a minimal set of such viewpoints. The viewpoint families we handle include (i) the set of viewing directions from infinity, (ii) viewpoints on a circle located outside the object (for inspection from a turntable), and (iii) viewpoints located on the walls of the shape itself. We compute a structure called a visibility chart, which simultaneously encodes the visible part of the shape's boundary from every view in the family. Using such a visibility chart, finding a minimal set of viewpoints reduces to the set-covering problem over the reals. Practical algorithms are obtained by a discrete sampling of the visibility chart. For exterior visibility problems, a reasonable approach is to compute an almost-optimal solution (in terms of number of viewpoints), which can be done in almost-linear time. For interior visibility problems, or when a more correct solution is required, we solve the general set-covering problem, guaranteeing an optimal solution but taking exponential time

Resting spontaneous baroreflex sensitivity and cardiac autonomic control in anabolic androgenic steroid users

OBJECTIVES: Misuse of anabolic androgenic steroids in athletes is a strategy used to enhance strength and skeletal muscle hypertrophy. However, its abuse leads to an imbalance in muscle sympathetic nerve activity, increased vascular resistance, and increased blood pressure. However, the mechanisms underlying these alterations are still unknown. Therefore, we tested whether anabolic androgenic steroids could impair resting baroreflex sensitivity and cardiac sympathovagal control. In addition, we evaluate pulse wave velocity to ascertain the arterial stiffness of large vessels. METHODS: Fourteen male anabolic androgenic steroid users and 12 nonusers were studied. Heart rate, blood pressure, and respiratory rate were recorded. Baroreflex sensitivity was estimated by the sequence method, and cardiac autonomic control by analysis of the R-R interval. Pulse wave velocity was measured using a noninvasive automatic device. RESULTS: Mean spontaneous baroreflex sensitivity, baroreflex sensitivity to activation of the baroreceptors, and baroreflex sensitivity to deactivation of the baroreceptors were significantly lower in users than in nonusers. In the spectral analysis of heart rate variability, high frequency activity was lower, while low frequency activity was higher in users than in nonusers. Moreover, the sympathovagal balance was higher in users. Users showed higher pulse wave velocity than nonusers showing arterial stiffness of large vessels. Single linear regression analysis showed significant correlations between mean blood pressure and baroreflex sensitivity and pulse wave velocity. CONCLUSIONS: Our results provide evidence for lower baroreflex sensitivity and sympathovagal imbalance in anabolic androgenic steroid users. Moreover, anabolic androgenic steroid users showed arterial stiffness. Together, these alterations might be the mechanisms triggering the increased blood pressure in this population

Creating a Charrette Process to Ignite the Conversation on Equity and Inclusion

The gaps in graduation and retention rates between ethnic and gender groups continue to be a foremost area of focus at Borough of Manhattan Community College (BMCC), The City University of New York (CUNY). Equity and inclusion is also a critical concern as it relates to faculty and staff. At BMCC, a college-wide initiative, Designing for Success, is seeking to improve declining retention and graduation rates. At its core is the question, “Have we designed our operations to produce these results?” The answer is, “Yes”. BMCC’s Designing for Success strategic planning process seeks to re-design administrative processes and teaching in an effort to eradicate these gaps through efforts which include a community-wide discussion and action planning on equity and inclusion inspired by the charrette process. The charrette creates small groups that meet on more than one occasion to identify critical barriers to addressing equity and inclusion and develops action plans for addressing these barriers from stakeholders at all levels of an organization. This paper proposes that public scholarship is at the core of the charrette process, that it is uniquely appropriate for the higher education environment and moves the community from a “discussion” of the barriers to fully engaging the entire college community in meaningful action-oriented strategic planning

A novel role of CD4 Th17 cells in mediating cardiac allograft rejection and vasculopathy

T-bet plays a crucial role in Th1 development. We investigated the role of T-bet in the development of allograft rejection in an established MHC class II–mismatched (bm12 into B6) model of chronic allograft vasculopathy (CAV). Intriguingly, and in contrast to IFN-γ−/− mice that are protected from CAV, T-bet−/− recipients develop markedly accelerated allograft rejection accompanied by early severe vascular inflammation and vasculopathy, and infiltration by predominantly IL-17–producing CD4 T cells. Concurrently, T-bet−/− mice exhibit a T helper type 1 (Th1)–deficient environment characterized by profound IFN-γ deficiency, a Th2 switch characterized by increased production of interleukin (IL) 4, IL-5, IL-10, and IL-13 cytokines, as well as increased production of the proinflammatory cytokines IL-6, IL-12p40, and IL-17. Neutralization of IL-17 inhibits accelerated allograft rejection and vasculopathy in T-bet−/− mice. Interestingly, CD4 but not CD8 T cell deficiency in T-bet−/− mice affords dramatic protection from vasculopathy and facilitates long-term graft acceptance. This is the first study establishing that in the absence of Th1-mediated alloimmune responses, CD4 Th17 cells mediate an aggressive proinflammatory response culminating in severe accelerated allograft rejection and vasculopathy. These results have important implications for the development of novel therapies to target this intractable problem in clinical solid organ transplantation