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In this article, a model-based micro-end milling process planning for machining micromold cavities is proposed. The goal is to facilitate proper selections of the process parameters for a given workpiece material, cavity geometry, and micro-end mill. Specifically, the axial depth of cut and the feed per tooth are critical in achieving performance objectives in terms of low cutting forces and high surface accuracy and material removal rate. An analytical model based on process mechanics is used to select feed per tooth range in micromilling to avoid size effects. Further, a time-domain simulation model is utilized to provide predictive capability in practical micromachining performance, such as cutting forces, surface form, and surface roughness. The generalized process planning strategy consists of two steps: roughing and finishing. In roughing, the objective is to control the cutting force within a predefined threshold to prevent premature tool breakage and to maximize the material removal rate. In finishing, the primary objective is to control the form error within the tolerance and to obtain satisfactory surface roughness. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of using acetylsalicylic acid (aspirin) together with lansoprazole in the secondary prevention of ischemic stroke., Materials and Methods: 199 patients with a diagnosis of ischemic stroke and transient ischemic attack (TIA) using 100 mg aspirin regularly were included in the study. All patients were evaluated for the presence of aspirin resistance before starting the study. 57 patients with aspirin resistance were excluded from the study. The remaining 142 patients were divided into two groups: the 1st group consisted of those with stomach discomfort and the 2nd group consisted of those without stomach discomfort. Patients in group 1 were given 30 mg of lansoprazole taken before breakfast in addition to aspirin therapy. All patients were re-evaluated for the presence of aspirin resistance at a one-month follow-up. The antiaggregant activity was evaluated by the impedance aggregometry method in both groups., Results: Of 142 patients, 75 were in group 1, and 67 were in group 2. There was no difference between the two groups in terms of age and gender distribution of vascular risk factors. There was no statistically significant difference between the two groups in terms of aspirin efficacy. The dose of aspirin was increased in patients with aspirin resistance (AR)., Conclusion: The combination of 30 mg lansoprazole and 100 mg aspirin does not cause a decrease in antiaggregant activity in the early period, but chronic use was not evaluated in this study. Patients with AR may benefit from an increase in the dose of aspirin.

This paper presents an integrated physics-based and statistical modeling approach to predict temperature field and meltpool geometry in multi-track processing of laser powder bed fusion (L-PBF) of nickel 625 alloy. Multi-track laser processing of powder material using L-PBF process has been studied using 2-D finite element simulations to calculate temperature fields along the scan and hatch directions for three consecutive tracks for a moving laser heat source to understand the heating and melting process. Based on the predicted temperature fields, width, depth and shape of the meltpool is determined. Designed experiments on L-PBF of nickel alloy 625 powder material are conducted to measure the relative density and meltpool geometry. Experimental work is reported on the measured density of built coupons and meltpool size. Statistically-based predictive models using response surface regression for relative density, meltpool geometry, peak temperature, and time above melting point are developed and multi-objective optimization studies are conducted by using genetic algorithm and swarm intelligence.

Laser powder bed fusion (L-PBF) as an additive manufacturing process produces nearly fully dense nickel alloy 625 (IN625) parts with complex features. L-PBF generates surfaces and microstructure through directional solidification that can be controlled by scan strategies and selection of process parameters. This study provides experimental investigations on microstructure formation including sizes of cellular grains and growth directions of columnar grains on the nickel alloy 625 test coupons. The effects of process parameters including laser power, scan velocity, hatch distance, and scan strategy that produce various solidification cooling rates and thermal gradients during the process, which also contribute to resultant microstructure, have been analyzed. Optimization studies are conducted on several objectives to improve the productivity while controlling the process effects on the resultant microstructure using response surface regression, desirability functions, and multi-objective genetic algorithm optimization.

Background and Objective: Nanotechnology offers the possibility of creating multi-functional structures that can provide solutions for biomedical problems. The nanoprobes herein described are an example of such structures, where nano-scaled particles have been designed to provide high specificity and contrast potential for optical detection of cancer. Specifically, enzymatically activated fluorescent nanoprobes (EANPs) were synthesized as cancer-specific contrast agents for optical imaging., Study Design/materials and Methods: EANPs were prepared by nanoprecipitation of blends of poly(lactic acid)-b-poly(ethylene glycol) and poly(lactic-co-glycolic acid)-b-poly(l-lysine). The lysine moieties were then covalently decorated with the near infrared (NIR) fluorescent molecule AlexaFluor-750 (AF750). Close proximity of the fluorescent molecules to each other resulted in fluorescence quenching, which was reversed by enzymatically mediated cleavage of poly(l-lysine) chains. EANPs were characterized by dynamic light scattering and electron microscopy. Enzymatic development of fluorescence was studied in vitro by fluorescence spectroscopy. Biocompatibility and contrast potential of EANPs were studied in cancerous and noncancerous cells. The potential of the nanoprobes as contrast agents for NIR fluorescence imaging was studied in tissue phantoms., Results: Spherical EANPs of ∼100 nm were synthesized via nanoprecipitation of polymer blends. Fluorescence activation of EANPs by treatment with a model protease was demonstrated with up to 15-fold optical signal enhancement within 120 minutes. Studies with MDA-MB-231 breast cancer cells demonstrated the cytocompatibility of EANPs, as well as enhanced fluorescence associated with enzymatic activation. Imaging studies in tissue phantoms confirmed the ability of a simple imaging system based on a laser source and CCD camera to image dilute suspensions of the nanoprobe at depths of up to 4 mm, as well as up to a 13-fold signal-to-background ratio for enzymatically activated EANPs compared to un-activated EANPs at the same concentration., Conclusion: Nanoprecipitation of copolymer blends containing poly(l-lysine) was utilized as a method for preparation of highly functional nanoprobes with high potential as contrast agents for fluorescence based imaging of cancer. Lasers Surg. Med. 47:579-594, 2015. © 2015 Wiley Periodicals, Inc., (© 2015 Wiley Periodicals, Inc.)