Improvements for Store-Collect and Atomic Snapshot Objects under Continuous Churn

The field of distributed computing has given rise to many algorithms to share data among nodes in a network. This work focuses on the store-collect and the atomic snapshot objects in an asynchronous, crash-prone message-passing dynamic system with nodes continuously entering and leaving the system. We assume that the maximum number of nodes that enter, leave or crash during some time interval is proportional to the size of the system. A store-collect object is a distributed object that allows nodes to store data in the system in a variable that can be read by all nodes, but only modified by the node that stored it. This is achieved through two basic operations: the store operation, which stores information into the network, and collect, which collects a copy of all the information stored by every node in the network at the beginning of the time interval in which the operation is active. The atomic snapshot object is quite similar. It provides two operations, scan and update, that behave in a very similar fashion to the collect and store operations given by the store-collect object; however the atomic snapshot object must satisfy the linearizability condition, which means that it is always possible to arrange all the operations performed into an ordered sequence even if there are operations that occur simultaneously. This work improves upon the store-collect and atomic snapshot implementations given in Attiya et al [SSS, 2020]. We developed a method for quantifying the churn of a network subject to certain assumptions. This new method allows us to prove the correctness of the store-collect algorithm under less restrictive conditions than those found in the original proof of Attiya et al. Additionally, we developed an improved implementation of the atomic snapshot object based on a store-collect object that requires fewer messages to complete a scan or an update operation

Functional characteristics of S-59 photochemically treated platelet concentrates derived from buffy coats

Background: A photochemical treatment (PCT) process for inactivation of infectious pathogens and leukocytes has been developed and evaluated using single-donor platelet concentrates. This study assessed the application of PCT to platelets prepared from pooled buffy coats. In this study, in vitro functional characteristics of PCT platelets were compared to control platelets prepared from pooled buffy coats using the approved platelet-additive solution T-Sol®. Platelets in platelet PAS III additive solution without PCT were evaluated as well. PCT also included the use of a psoralen (S-59) reduction device (SRD). Materials and Methods: Four types of platelet concentrates were compared: (1) platelet concentrate in plasma/T-Sol; (2) platelet concentrate in plasma/PAS III; (3) platelet concentrate in plasma/PAS III, PCT, 9 h SRD and (4) platelet concentrate in plasma/PAS III, PCT, 16 h SRD. PCT occurred on the day after whole-blood collection. In vitro assay parameters included: pH, pO 2, pCO 2, HCO 3,/ - platelet count, mean platelet volume, plasma glucose, plasma lactate, total ATP, expression of p-selectin, hypotonic shock response and electron microscopy. Results: The results indicate that PCT is compatible with platelet concentrates prepared from pooled buffy coats for up to 7 days of storage. Conclusion: The PCT process resulted in acceptable in vitro platelet functional characteristics and is currently in clinical trials to evaluate the haemostatic efficacy of PCT platelets in thrombocytopenic patients requiring multiple platelet transfusions. Copyrigh

One-stop microvascular screening service: an effective model for the early detection of diabetic peripheral neuropathy and the high-risk foot.

AIMS: To evaluate the feasibility of a one-stop microvascular screening service for the early diagnosis of diabetic distal symmetrical polyneuropathy, painful distal symmetrical polyneuropathy and the at-risk diabetic foot. METHODS: People with diabetes attending retinal screening in hospital and community settings had their feet examined by a podiatrist. Assessment included: Toronto Clinical Neuropathy Score evaluation; a 10-g monofilament test; and two validated, objective and quick measures of neuropathy obtained using the point-of-care devices 'DPN-Check', a hand-held device that measures sural nerve conduction velocity and amplitude, and 'Sudoscan', a device that measures sudomotor function. The diagnostic utility of these devices was assessed against the Toronto Clinical Neuropathy Score as the 'gold standard'. RESULTS: A total of 236 consecutive people attending the retinal screening service, 18.9% of whom had never previously had their feet examined, were evaluated. The prevalence of distal symmetrical polyneuropathy, assessed using the Toronto Clinical Neuropathy Score, was 30.9%, and was underestimated by 10-g monofilament test (14.4%). The prevalence of distal symmetrical polyneuropathy using DPN-check was 51.5% (84.3% sensitivity, 68.3% specificity), 38.2% using Sudoscan foot electrochemical skin conductance (77.4% sensitivity, 68.3% specificity), and 61.9% using abnormality in either of the results (93.2% sensitivity, 52.8% specificity). The results of both devices correlated with Toronto Clinical Neuropathy Score (P<0.001). A new diagnosis of painful distal symmetrical polyneuropathy was made in 59 participants (25%), and 56.6% had moderate- or high-risk foot. Participants rated the service very highly. CONCLUSIONS: Combined, eye, foot and renal screening is feasible, has a high uptake, reduces clinic visits, and identifies painful distal symmetrical polyneuropathy and the at-risk foot. Combined large- and small-nerve-fibre assessment using non-invasive, quantitative and quick point-of-care devices may be an effective model for the early diagnosis of distal symmetrical polyneuropathy

Last days in the old radiation laboratory (ORL), Berkeley, California, 1954

Govindjee, the founding editor of the Historical Corner of Photosynthesis Research, invited me 3 years ago to tell the story of why I left Melvin Calvin’s laboratory in the mid 1950s long before the 1961 Nobel Prize in Chemistry was awarded to Calvin for the path of carbon in photosynthesis. I have already written my scientific perspective on this topic (see Benson (Photosynth Res 73:29–49, 2002); also see Bassham (Photosynth Res 76:35–52, 2003) as he was also a major player in this research). Here, I present my recollections of my last days in the old radiation laboratory (ORL) at Berkeley, California. References have been added by Govindjee for the benefit of the readers

Diabetic peripheral neuropathy : advances in diagnosis and strategies for screening and early intervention

Diabetic peripheral neuropathy (DPN) is a common complication of both type 1 and 2 diabetes. It is a leading cause of lower-limb amputation and disabling neuropathic pain. Amputations in patients with diabetes have a devastating effect on quality of life and are associated with an alarmingly low life expectancy (on average only 2 years from the amputation). Amputation also places a substantial financial burden on health-care systems and society in general. With the introduction of national diabetes eye screening programmes, the prevalence of blindness in working-age adults is falling. This is not the case, however, with diabetes related amputations. In this Review, we appraise innovative point-of-care devices that enable the early diagnosis of DPN and assess the evidence for early risk factor-based management strategies to reduce the incidence and slow the progression of DPN. We also propose a framework for screening and early multifactorial interventions as the best prospect for preventing or halting DPN and its devastating sequelae

SUDOSCAN: A Simple, Rapid, and Objective Method with Potential for Screening for Diabetic Peripheral Neuropathy.

Clinical methods of detecting diabetic peripheral neuropathy (DPN) are not objective and reproducible. We therefore evaluated if SUDOSCAN, a new method developed to provide a quick, non-invasive and quantitative assessment of sudomotor function can reliably screen for DPN. 70 subjects (45 with type 1 diabetes and 25 healthy volunteers [HV]) underwent detailed assessments including clinical, neurophysiological and 5 standard cardiovascular reflex tests (CARTs). Using the American Academy of Neurology criteria subjects were classified into DPN and No-DPN groups. Based on CARTs subjects were also divided into CAN, subclinical-CAN and no-CAN. Sudomotor function was assessed with measurement of hand and foot Electrochemical Skin Conductance (ESC) and calculation of the CAN risk score. Foot ESC (μS) was significantly lower in subjects with DPN [n = 24; 53.5(25.1)] compared to the No-DPN [77.0(7.9)] and HV [77.1(14.3)] groups (ANCOVA p<0.001). Sensitivity and specificity of foot ESC for classifying DPN were 87.5% and 76.2%, respectively. The area under the ROC curve (AUC) was 0.85. Subjects with CAN had significantly lower foot [55.0(28.2)] and hand [53.5(19.6)] ESC compared to No-CAN [foot ESC, 72.1(12.2); hand ESC 64.9(14.4)] and HV groups (ANCOVA p<0.001 and 0.001, respectively). ROC analysis of CAN risk score to correctly classify CAN revealed a sensitivity of 65.0% and specificity of 80.0%. AUC was 0.75. Both foot and hand ESC demonstrated strong correlation with individual parameters and composite scores of nerve conduction and CAN. SUDOSCAN, a non-invasive and quick test, could be used as an objective screening test for DPN in busy diabetic clinics, insuring adherence to current recommendation of annual assessments for all diabetic patients that remains unfulfilled