51 research outputs found

    Accelerating phase unwrapping and affine transformations for optical quadrature microscopy using CUDA

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    Optical Quadrature Microscopy (OQM) is a process which uses phase data to capture information about the sample being studied. OQM is part of an imaging framework developed by the Optical Science Laboratory at Northeastern University. In one particular application of interest, the framework is used to extract phase information from the image of an embryo to determine embryo viability. Phase Unwrapping is the process of reconstructing the real phase shift (propagation delay) of a sample from the measured “wrapped“ representation which is between −π and +π. Unwrapping can be done using the Minimum L P Norm Phase Unwrap algorithm. Images are first preprocessed using an Affine Transform before they are unwrapped. Both of these steps are time consuming and would benefit greatly from parallelization and acceleration. Faster processing would lower many research barriers (in terms of throughpu

    Pancreas Transplantation: Does Age Increase Morbidity?

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    Introduction. Pancreas transplantation (PTx) is the only definitive intervention for type 1 diabetes. Medical advancements in diabetes care have led to an aging PTx candidate pool. We report our experience with patients ≥50 years of age undergoing PTx. Methods. We reviewed 136 consecutive PTx patients at our institution from 1996–2010; 17 were ≥50 years of age. We evaluated demographics, surgical complications, acute rejection (AR) rates, nonsurgical infections, and survival outcomes. Results. Demographic data was similar (P > .05) between groups, excluding age. The two groups had comparable major and minor surgical complication rates (P = .10 and P = .25, resp.). The older group had a lower 1-year and overall AR rate (P = .04 and P = .03, resp.). The incidence of non-surgical infections and overall patient and graft survival was similar between groups (P > .05). Conclusion. Older patients with type 1 diabetes are feasible candidates for PTx, as surgical morbidity, incidence of infections, and AR rates are low

    Single Port Donor Nephrectomy

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    In 2007, Rane presented the first single port nephrectomy for a small non-functioning kidney at the World Congress of Endourology. Since that time, the use of single port surgery for nephrectomy has expanded to include donor nephrectomy. Over the next two years the technique was adopted for many others types of nephrectomies to include donor nephrectomy. We present our technique for single port donor nephrectomy using the Gelpoint device. We have successfully performed this surgery in over 100 patients and add this experience to our experience of over 1000 laparoscopic nephrectomies. With the proper equipment and technique, single port donor nephrectomy can be performed safely and effectively in the majority of live donors. We have found that our operative times and most importantly our transplant outcomes have not changed significantly with the adoption of the single port donor nephrectomy. We believe that single port donor nephrectomy represents a step forward in the care of living donors

    Risk aversion in the use of complex kidneys in paired exchange programs: Opportunities for even more transplants?

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    This retrospective review of the largest United States kidney exchange reports characteristics, utilization, and recipient outcomes of kidneys with simple compared to complex anatomy and extrapolates reluctance to accept these kidneys. Of 3105 transplants performed, only 12.8% were right kidneys and 23.1% had multiple renal arteries. 59.3% of centers used fewer right kidneys than expected and 12.1% transplanted zero right kidneys or kidneys with more than 1 artery. Five centers transplanted a third of these kidneys (35.8% of right kidneys and 36.7% of kidneys with multiple renal arteries). 22.5% and 25.5% of centers currently will not entertain a match offer for a left or right kidney with more than one artery, respectively. There were no significant differences in all-cause graft failure or death-censored graft loss for kidneys with multiple arteries, and a very small increased risk of graft failure for right kidneys versus left of limited clinical relevance for most recipients. Kidneys with complex anatomy can be used with excellent outcomes at many centers. Variation in use (lack of demand) for these kidneys reduces the number of transplants, so systems to facilitate use could increase demand. We cannot know how many donors are turned away because perceived demand is limited.Wiley Read-and-Publish Agreemen

    Side-Channel Analysis of MAC-Keccak Hardware Implementations

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    As Keccak has been selected as the new SHA-3 standard, Message Authentication Code (MAC) (MAC-Keccak) using a secret key will be widely used for integrity checking and authenticity assurance. Recent works have shown the feasibility of side-channel attacks against software implementations of MAC-Keccak to retrieve the key, with the security assessment of hardware implementations remaining an open problem. In this paper, we present a comprehensive and practical side-channel analysis of a hardware implementation of MAC-Keccak on FPGA. Different from previous works, we propose a new attack method targeting the first round output of MAC-Keccak rather than the linear operation θ\theta only. The results on sampled power traces show that the unprotected hardware implementation of MAC-Keccak is vulnerable to side-channel attacks, and attacking the nonlinear operation of MAC-Keccak is very effective. We further discuss countermeasures against side-channel analysis on hardware MAC-Keccak. Finally, we discuss the impact of the key length on side-channel analysis and compare the attack complexity between MAC-Keccak and other cryptographic algorithms

    Development and Assessment of a Systematic Approach for Detecting Disparities in Surgical Access

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    IMPORTANCE: Although optimal access is accepted as the key to quality care, an accepted methodology to ascertain potential disparities in surgical access has not been defined. OBJECTIVE: To develop a systematic approach to detect surgical access disparities. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study used publicly available data from the Health Cost and Utilization Project State Inpatient Database from 2016. Using the surgical rate observed in the 5 highest-ranked counties (HRCs), the expected surgical rate in the 5 lowest-ranked counties (LRCs) in North Carolina were calculated. Patients 18 years and older who underwent an inpatient general surgery procedure and patients who underwent emergency inpatient cholecystectomy, herniorrhaphy, or bariatric surgery in 2016 were included. Data were collected from January to December 2016, and data were analyzed from March to July 2020. EXPOSURES: Health outcome county rank as defined by the Robert Wood Johnson Foundation. MAIN OUTCOMES AND MEASURES: The primary outcome was the proportional surgical ratio (PSR), which was the disparity in surgical access defined as the observed number of surgical procedures in the 5 LRCs relative to the expected number of procedures using the 5 HRCs as the standardized reference population. RESULTS: In 2016, approximately 1.9 million adults lived in the 5 HRCs, while approximately 246 854 lived in the 5 LRCs. A total of 28 924 inpatient general surgical procedures were performed, with 4521 being performed in those living in the 5 LRCs and 24 403 in those living in the 5 HRCs. The rate of general surgery in the 5 HRCs was 13.09 procedures per 1000 population. Using the 5 HRCs as the reference, the PSR for the 5 LRCs was 1.40 (95% CI, 1.35-1.44). For emergent/urgent cholecystectomy, the PSR for the 5 LRCs was 2.26 (95% CI, 2.02-2.51), and the PSR for emergent/urgent herniorrhaphy was 1.83 (95% CI, 1.33-2.45). Age-adjusted rate of obesity (body mass index [calculated as weight in kilograms divided by height in meters squared] greater than 30), on average, was 36.6% (SD, 3.4) in the 5 LRCs vs 25.4% (SD, 4.6) in the 5 HRCs (P = .002). The rate of bariatric surgery in the 5 HRCs was 33.07 per 10 000 population with obesity. For the 5 LRCs, the PSR was 0.60 (95% CI, 0.51-0.69). CONCLUSIONS AND RELEVANCE: The PSR is a systematic approach to define potential disparities in surgical access and should be useful for identifying, investigating, and monitoring interventions intended to mitigate disparities in surgical access that effects the health of vulnerable populations

    Power analysis attack on hardware implementation of MAC-Keccak on FPGAs

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    Abstract. Keccak is the hash function selected by NIST as the new SHA-3 standard. Keccak is built on Sponge construction and it provides a new MAC function called MAC-Keccak. These new algorithms have raised questions with regards to side-channel leakage and analysis attacks of MAC-Keccak. So far there exists prior work on attacks of software implementations of MAC-Keccak, but there has been no comprehensive side-channel vulnerability assessment of its hardware implementation. In this paper we describe an attack on the θ step of the first round of MAC-Keccak implemented on an FPGA. We construct several different side-channel leakage models and implement attacks based on them. Our work shows that an unmasked hardware implementation of SHA-3 is vulnerable to power-based side-channel attacks. 1 introduction Keccak was selected as the winner of the NIST hash function competition in 2012 to become the SHA-3 standard [1]. Keccak uses the Sponge construction [2] in which message blocks are XORed into the state bits and then invertibly permuted [3]. Sponge construction is completely different from the previous hash standards and thus opens up new questions and challenges in side-channel analysis (SCA). A message authentication code (MAC) is a short piece of information generated by hash function
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