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Making public health data easier to access, understand, and use makes it more likely that the data will be influential. Throughout the COVID-19 pandemic, the New York City (NYC) Department of Health and Mental Hygiene’s Web-based data communication became a cornerstone of NYC’s response and allowed the public, journalists, and researchers to access and understand the data in a way that supported the pandemic response and brought attention to the deeply unequal patterns of COVID-19’s morbidity and mortality in NYC. (Am J Public Health. 2021;111(S3):S193–S196. https://doi.org/10.2105/AJPH.2021.306446 )

Background HIV self-tests increase HIV status awareness by providing convenience and privacy, although cost and access may limit use. Since 2015, the New York City (NYC) Health Department has conducted 5 waves of an online Home Test Giveaway. Methods We recruited adult cisgender men who have sex with men (MSM) and transgender and gender-nonconforming (TGNC) individuals who had sex with men, who were living in NYC, not previously HIV diagnosed, and using paid digital advertisements (4-8 weeks per wave). Eligible respondents were e-mailed a code to redeem on the manufacturer's website for a free HIV self-test and an online follow-up survey ~2 months later. For key process and outcome measures, we present means across 5 waves. Results Across the 5 waves of Home Test Giveaway, there were 28,921 responses to the eligibility questionnaire: 17,383 were eligible, 12,182 redeemed a code for a free HIV self-test, and 7935 responded to the follow-up survey (46% of eligible responses). Among eligible responses, approximately half were Latino/a (mean, 32%) or non-Latino/a, black (mean, 17%). Mean report of never testing before was 16%. Among 5903 follow-up survey responses who reported test use, 32 reported reactive results with no known previous diagnosis (0.54%), of whom 78% reported receiving confirmatory testing. Report of likelihood of recommending the Home Test Giveaway to friends was high (mean, 96%). Conclusions We recruited diverse NYC MSM and TGNC and distributed a large number of HIV self-tests to them. Among respondents who reported newly reactive tests, the majority reported confirmatory testing. This seems to be one acceptable way to reach MSM and TGNC for HIV testing, including those who have never tested before.

There are very few cases of malignant mesothelioma (MM) presenting as interstitial lung disease (ILD) reported in the literature, and distinguishing this rare subtype of MM from nonmalignant etiolo...

Background Intracavitary pulmonary aspergilloma is a chronic, debilitating fungal infection. Without definitive therapy, death can occur from massive hemoptysis, cachexia, or secondary infection. Although surgical resection is the standard therapy, it is not possible for many patients owing to poor pulmonary function or medical comorbidities. Aspergilloma removal through bronchoscopy is an important alternative therapy that may be available in select cases. Methods We retrospectively reviewed all cases referred to the University of Calgary Interventional Pulmonary Service for transbronchial removal of intracavitary aspergilloma from January 1, 2009, to January 1, 2014. Results Ten patients with intracavitary pulmonary aspergilloma were identified. In 3 patients, the aspergilloma cavity was not accessible by bronchoscopy. Successful removal of the aspergilloma with symptom improvement or resolution was achieved in 6 of 7 cases. One of the patients was lost to follow-up. Minor hypoxia lasting 12 to 72 hours was observed in 5 cases. Severe sepsis requiring an extended critical care unit stay occurred in 1 case. Follow-up ranged from 9 months to 5 years. Conclusions Although not without risk of minor hypoxia and possible sepsis, for carefully selected patients, bronchoscopic removal of symptomatic intracavitary pulmonary aspergilloma may be an alternative therapy to surgical resection for this life-threatening disease.

Routing in Delay Tolerant Networks is very challenging because of frequent disconnections. One cause of disconnection is node movement. Disconnections can be overcome by finding a set of sequential opportunistic encounters between pairs of mobile nodes. These encounters can be used for message forwarding and delivery. In this context, understanding user mobile behaviour is essential to design effective and efficient network protocols. This paper presents a generic methodology to model and find periodic encounter patterns by using the auto-persistence function and detection techniques derived from it. From the studies on four real mobility traces, we are able to detect strong weekly periodic encounter patterns with an accuracy of up to 100%. The experimental results show that periodic encounter patterns in real mobility traces do not last long, e.g., years, because they are interrupted by unexpected events from time to time. Nonetheless our experimental results show that those periodic encounters can still last up to a few months. Furthermore, we show that, for some of the mobility traces, the network formed by periodic encounters forms a small-world structure.

Background Perioperative hypothermia has been reported to increase the occurrence of cardiovascular complications. By increasing the activity of sympathetic nervous system, perioperative hypothermia also has the potential to increase cardiac injury and dysfunction associated with subarachnoid hemorrhage. Methods The Intraoperative Hypothermia for Aneurysm Surgery Trial randomized patients undergoing cerebral aneurysm surgery to intraoperative hypothermia (n = 499, 33.3 degrees +/- 0.8 degrees C) or normothermia (n = 501, 36.7 degrees +/- 0.5 degrees C). Cardiovascular events (hypotension, arrhythmias, vasopressor use, myocardial infarction, and others) were prospectively followed until 3-month follow-up and were compared in hypothermic and normothermic patients. A subset of 62 patients (hypothermia, n = 33; normothermia, n = 29) also had preoperative and postoperative (within 24 h) measurement of cardiac troponin-I and echocardiography to explore the association between perioperative hypothermia and subarachnoid hemorrhage-associated myocardial injury and left ventricular function. Results There was no difference between hypothermic and normothermic patients in the occurrence of any single cardiovascular event or in composite cardiovascular events. There was no difference in mortality (6%) between groups, and there was only a single primary cardiovascular death (normothermia). There was no difference between hypothermic and normothermic patients in postoperative versus preoperative left ventricular regional wall motion or ejection fraction. Compared with preoperative values, hypothermic patients had no postoperative increase in cardiac troponin-I (median change 0.00 microg/l), whereas normothermic patients had a small postoperative increase (median change + 0.01 microg/l, P = 0.038). Conclusion In patients undergoing cerebral aneurysm surgery, perioperative hypothermia was not associated with an increased occurrence of cardiovascular events.

Background Rapid intravenous injection of oxytocin is associated with marked hypotension secondary to decreased venous return. Reductions in dose and rate of bolus administration have reduced the incidence of cardiovascular side effects, but no study has yet investigated cardiovascular stability when oxytocin is infused for several hours after delivery. This study compared maternal haemodynamics during a 4-h 30-unit oxytocin infusion and during a placebo infusion following caesarean section. Methods Women booked for elective caesarean section were randomised to receive either oxytocin 5-unit bolus and placebo infusion or oxytocin 5-unit bolus and oxytocin 30-unit infusion. Before, during and for 4 h after surgery electrocardiogram, oxygen saturation, systolic and diastolic pressure and heart rate were monitored non-invasively and cardiac index (CI), left ventricular work index (LVWi) and systemic vascular resistance index (SVRi) by thoracic bioimpedance. Results A total of 74 women agreed to haemodynamic measurements. Heart rate, systolic and diastolic pressure, CI, LCWi and SVRi all fell following the onset of spinal anaesthesia, and, with the exception of SVRi, continued to decrease throughout surgery. After delivery of the baby, slow injection of oxytocin 5 units was associated with a temporary rise in CI, LCWi and heart rate, a decrease in SVRi and no change in systolic or diastolic pressure. Thereafter, haemodynamic measures returned to normal over 60 min with no adverse effects apparent from the additional oxytocin infusion. Conclusions An additional oxytocin infusion at elective caesarean section did not adversely affect maternal haemodynamics either during or after surgery.

Background Although hypothermia and barbiturates improve neurologic outcomes in animal temporary focal ischemia models, the clinical efficacy of these interventions during temporary occlusion of the cerebral vasculature during intracranial aneurysm surgery (temporary clipping) is not established. Methods A post hoc analysis of patients from the Intraoperative Hypothermia for Aneurysm Surgery Trial who underwent temporary clipping was performed. Univariate and multivariate logistic regression methods were used to test for associations between hypothermia, supplemental protective drug, and short- (24-h) and long-term (3-month) neurologic outcomes. An odds ratio more than 1 denotes better outcome. Results Patients undergoing temporary clipping (n = 441) were assigned to intraoperative hypothermia (33.3 degrees +/- 0.8 degrees C, n = 208) or normothermia (36.7 degrees +/- 0.5 degrees C, n = 233), with 178 patients also receiving supplemental protective drug (thiopental or etomidate) during temporary clipping. Three months after surgery, 278 patients (63%) had good outcome (Glasgow Outcome Score = 1). Neither hypothermia (P = 0.847; odds ratio = 1.043, 95% CI = 0.678-1.606) nor supplemental protective drug (P = 0.835; odds ratio = 1.048, 95% CI = 0.674-1.631) were associated with 3-month Glasgow Outcome Score. The effect of supplemental protective drug did not significantly vary with temperature. The effects of hypothermia and protective drug did not significantly vary with temporary clip duration. Similar findings were made for 24-h neurologic status and 3-month Neuropsychological Composite Score. Conclusion In the Intraoperative Hypothermia for Aneurysm Surgery Trial, neither systemic hypothermia nor supplemental protective drug affected short- or long-term neurologic outcomes of patients undergoing temporary clipping.

The Internet relies on cooperative endpoints to react to signals from the network that congestion is occurring. In particular, TCP interprets packet loss as a signal of congestion. However there are many new non-cooperative protocols in use which attempt to exploit the network aggressively and do not reduce their demands when the network signals congestion. We propose the aggregate control of ''fluxes'' defined by policies at individual routers. Each router can then calculate an optimal allocation of bandwidth to each flux contending for a given output link. We propose a combined hill climbing and convex programming method for this optimization, which we call HCCP. HCCP is designed to punish greedy fluxes rather than just regulating them: such fluxes may find their bandwidth allocation reduced to zero if they are sufficiently aggressive. Our results show that HCCP is effective at regulating a wide range of rather generally characterized transport protocols. We explore the use of both throughput maximization and proportionally fair allocation and recommend the latter because the former often leads to the situation where one or more fluxes receive zero bandwidth.

The selective-acknowledgement transmission control protocol (SACK TCP) is the most up-to-date version of TCP commonly used in the Internet. Understanding the resilience behaviour of SACK TCP is very important because congestion episodes and failure events are relatively frequent. In this paper, the descriptive power of Petri nets is leveraged to present the reactions that take place inside SACK TCP when network failures or congestion occur. An algebraic model is also presented that can be used to calculate the critical number of lost segments, nC, above which SACK TCP resilience is significantly degraded.

BACKGROUND: Hepatic portal venous gas (HPVG) is a rare condition that occurs when intraluminal gas and/or gas produced by intestinal bacteria enters the portal venous circulation. The most common precipitating factors include ischemia, intra-abdominal abscesses and inflammatory bowel disease. However, HPVG has recently been recognized as a rare complication of endoscopic and radiological procedures. Earlier studies advised immediate surgical intervention, but according to current recommendations, in some settings, HPVG can be managed conservatively. The present study reports two cases of HPVG; one that occurred following colonoscopy in a patient with severe Crohn’s disease and one in a patient with graft-versus-host disease.METHODS: The epidemiology, pathogenesis, diagnosis and management of HPVG are reviewed. Two case reports are presented, followed by the development of a management algorithm.RESULTS: Of the two patients that developed HPVG, one was an outpatient undergoing a colonoscopy for assessment of Crohn’s disease activity and the other was an inpatient with graft-versus-host disease. Once the diagnosis of HPVG was made, both patients were managed conservatively with antibiotic therapy and management of their underlying disease.CONCLUSIONS: HPVG can occur in the setting of severe gastrointestinal disease states and following endoscopic procedures. It is critical that gastroenterologists are aware of the differential diagnosis, pathogenesis, diagnostic approach and management of HPVG.

In this paper, we present a scheduler that incorporates round robin service within a VirtualClock discipline. Time-stamp based scheduling algorithms attain a low local delay bound and performance guarantee, but are computationally complex. On the other hand, round robin schemes are simple to implement and have computational complexity of O(1) but they are well known for their output burstiness and short-term unfairness. In order to overcome this problem, we combine round robin with VirtualClock in an algorithm we call VCRR. VCRR possesses better fairness than simple round robin, low jitter and a good scheduling delay bound. At the same time, VCRR preserves the O(1) time complexity of round robin. Simulation experiments show VCRR's efficiency in terms of delay performance, jitter and fairness..

Radiologic signs are recognizable, characteristic patterns used to describe abnormalities visualized on imaging modalities that ultimately aid in the diagnosis and subsequent treatment of disease. This pictorial essay discusses 23 classic roentgenographic signs used in thoracic imaging. Its purpose is to be used as an educational review for residents, whether they are beginning their training or preparing for certification exams, and serve as a refresher and a reference to the practicing radiologist.

Background: The in vivo survival of autologous fresh and preserved platelets can be measured using 51-Cr and 111-In-oxine radioisotope procedures and by a non-radioisotope procedure using biotin-X-N-hydroxysuccinimide (NHS) with detection in the flow cytometer using fluorescent streptavidin. This study was done to assess the specificity of the radioisotopes 51-Cr and 111-In-oxine and non-radioactive biotin-X-NHS to label platelets to measure their in vivo recovery and lifespan. Study design and methods: In the study reported here, aliquots of autologous platelets from the same baboon were labeled with 51-Cr, 111-In oxine and biotin-X-NHS to measure platelet survival. Both cell-associated and platelet-associated 51-Cr and 111-In oxine radioactivity were assessed to measure the in vivo recovery and lifespan of platelets. Blood volume was measured using the 125I albumin plasma volume and the total body hematocrit. Results: In vivo recovery values measured during the 1–3h post-infusion period and during the 8day post-infusion period showed significant differences between the 51-Cr-labeled and the 111-In-oxine labeled platelets. In the 51-Cr-labeled platelets, the cell-associated radioactivity was about 50% higher than the platelet-associated radioactivity. In the 111-In-oxine labeled platelets, the cell-associated radioactivity was about 10% higher than the platelet-associated radioactivity. Similar in vivo recovery values were observed in the biotin-X-NHS labeled platelets and the 111-In-oxine labeled platelets assessed from the cell-associated 111-In-radioactivity. Conclusion: The radioisotope 51-Cr and 111-In are non-specific labels for platelets, whereas biotin-X-NHS is a specific label for platelets identified in the flow cytometer with fluorescent streptavidin. The in vivo recovery values of autologous baboon platelets were similar when assessed from the cell-associated 111-In-oxine radioactivity and biotin-X-NHS labeled platelets.

Network routers rely on content addressable memories (CAMs) to accelerate the process of looking up the next hop of a packet. The input for this lookup is the destination address of the packet. This article describes our implementation and evaluation of a versatile prototype for a CAM. This prototype allows the empirical evaluation of the idea of caching lookup results in a multizone cache organized according to the length of the network prefix portion of the addresses. Implementing a cache in an FPGA efficiently required the design of a new cache replacement policy, the Bank N th Chance policy. In this article we present results from a functional simulator that allows the comparison of this new policy with existing ones such as least recently used, first in, first out and Second Chance. With a complete and functional prototype in a Xilinx Virtex 2000E device, we also report frequency of operation and occupation of the device. We present programmable logic design techniques that enable the implementation of ternary logic CAM cells, the efficient implementation of the new policy reference fields, and the pipelining of lookups.

BACKGROUND: RBC volume, 24-hour posttransfusion survival, and life span can be measured with radioisotopes and nonradioactive procedures. STUDY DESIGN AND METHODS: RBC volume was measured directly with autologous baboon RBCs labeled with biotin-X-N-hydroxysuccinimide (NHS), 51 Cr, 99m Tc, and 111 In-oxine and indirectly from the 125 I plasma volume and the total body Hct. Twenty-four-hour posttransfusion survival and life span were measured in autologous fresh baboon RBCs labeled with 51 Cr, 111 In-oxine, 99m Tc, and biotin-X-NHS. RESULTS: Significantly larger RBC volumes were observed when the fresh autologous RBCs were labeled with 51 Cr, 111 In-oxine, or 99m Tc than when they were labeled with the nonradioactive biotin-X-NHS. Twenty-four-hour posttransfusion survival values were significantly lower in the RBCs labeled with 111 In-oxine or 99m Tc than in the RBCs labeled with 51 Cr. CONCLUSIONS: The greater in vivo elution of 51 Cr, 111 In-oxine, and 99m Tc than that of biotin-X-NHS influenced the measurements of RBC volume, 24-hour posttransfusion survival, and life span of the fresh baboon RBCs.

Many disasters take place in urban areas, affecting millions of people each year through loss of life, serious injury and loss of assets and livelihoods. Poorer groups are generally most affected. The impact of these disasters and their contribution to poverty are underestimated, as is the extent to which rapidly growing and poorly managed urban development increases the risks. But urban specialists do not see disasters and disaster prevention as being within their remit. At the same time, few national and international disaster agencies have worked with urban governments and community organizations to identify and act on the urban processes that cause the accumulation of disaster risk in and around urban areas. This paper summarizes the discussions from a workshop funded by UNDP on the links between disasters and urban development in Africa, highlighting the underestimation of the number and scale of urban disasters, and the lack of attention to the role of urban governance. It notes the difficulties in getting action in Africa, since the region’s problems are still perceived as “rural” by disaster and development specialists, even though two-fifths of its population live in urban areas. It emphasizes the need for an understanding of risk that encompasses events ranging from disasters to everyday hazards and which understands the linkages between them – in particular, how identifying and acting on risks from “small” disasters can reduce risks from larger ones. It also stresses the importance of integrating such an understanding into poverty reduction strategies.

Due to the widening gap between the performance of microprocessors and that of memory, using caches in a system to take advantage of locality in its workload has become a standard approach to improve overall system performance. At the same time, many performance problems finally reduce to cache performance issues. Locality in system workload is the fact that makes caching possible. In this paper, we first use the reuse distance model to characterize temporal locality in Internet traffic. We develop a model that closely matches the empirical data. We then extend the work to investigate temporal locality in the workload of multi-processor forwarding systems by comparing locality under different packet scheduling schemes. Our simulations show that for systems with hash-based schedulers, caching can be an effective way to improve forwarding performance. Based on flow-level traffic characteristics, we further discuss the relationship between load-balancing and hash-scheduling, which yields insights into system design. Copyright © 2003 John Wiley & Sons, Ltd.

BACKGROUND : The survival of fresh and preserved platelets has been used primarily to determine their therapeutic effectiveness. The function of the fresh and preserved platelets has been difficult to assess. In stable thrombocytopenic patients, platelet function of fresh and preserved allogeneic platelets is evaluated by the reduction in bleeding time. In this study of healthy male baboons, both the survival and function of autologous fresh, liquid-preserved, and cryopreserved platelets in the correction of an aspirin-induced thrombocytopathy was evaluated. STUDY DESIGN AND METHODS : Five healthy male baboons were studied on eight occasions over a 4-year period. To produce a prolonged bleeding time, the baboon was administered 325 mg of aspirin 18 hours before receiving autologous transfusion. The fresh, liquid-preserved, and previously frozen washed platelets were labeled with 111 In-oxine before autologous transfusion. The autologous, nonaspirinated platelets' ability to reduce the aspirin-induced prolonged bleeding time and increase the shed blood thromboxane B 2 level at the template bleeding time site was studied. RESULTS : Platelets stored at 22°C for 48 hours had in vivo recovery values similar to those platelets stored for 18 hours, and they significantly reduced the bleeding time and increased the shed blood thromboxane level after transfusion. Platelets stored at 22°C for 72 hours had in vivo recovery values similar to those platelets stored for 18 hours, but the bleeding time was not corrected after transfusion, although there was a significant increase in the shed blood thromboxane B 2 level. The cryopreserved platelets significantly reduced the bleeding time and significantly increased the shed blood thromboxane level after transfusion. Cryopreserved platelets had better in vivo survival and function than the 5-day liquid-stored platelets. CONCLUSIONS : The survival of autologous fresh, liquid-preserved, or cryopreserved platelets did not correlate with their function to reduce an increased bleeding time in baboons treated with aspirin.

Both the spatial and temporal distributions of received signal power in wireless communications are often modeled as log-normal without any further discussion. This paper presents a field study of temporal signal fading in a test site situated in an area of boreal forest near Mandy Lake, Alberta. In it we give a statistical verification of the assumption that temporal signal fading obeys the log-normal distribution. Some conclusions based on wireless signal propagation are also made.

We report preliminary results from a novel method that predicts the value of the RF path loss exponent (PLE) from satellite remote-sensing observations. The value of the PLE is required when designing wireless sensor networks for environmental monitoring. The model was produced by correlating field measurements of path loss to Landsat 8 data for three dates in 2013. The correlations are strong (R2 > 0.87), and exhibit high statistical significance (p < 0.01). As far as we know, this is the first reported work that links remote sensing observations to field predictions of RF loss. The work reported here is preliminary because we were only able to gather field observations for three dates in 2013. Now that we know the approach holds some promise, we plan to extend the work with a much more aggressive field campaign in the spring and summer of 2014.

This paper presents preliminary results of a progressive research work investigating effects of vegetation on RF propagation. A theoretical model is developed to predict signal loss due to vegetation. The model considers path segments of different vegetation densities where the density measurements are available from satellite data. Signal loss over the entire propagation path is calculated by predicting and combining losses over individual segments. The model predicts vegetation loss factor (VLF) over each segment and then calculates the overall VLF of a path traversing multiple segments. The model has been validated against field data. Further modification of the model to include the effects of other environmental factors and different signal frequencies is under way.

In MANETs, communication often relies on finding a set of sequential opportunistic encounters between pairs of mobile nodes. In this context, understanding mobile node behaviour is essential to design effective and efficient network protocols. One characteristic that emerges from node mobility is that mobile nodes often have periodic behaviours. In this paper we take advantage of periodically repeated encounters between nodes. Given these encounter patterns, we show how to model routing as an optimization problem in a graph with a domain-specific constraint. Further, we propose polynomial time algorithms to find the optimal and near-optimal solutions. Experimental results show that our proposed approaches always find better routes compared to other state-of-the-art protocols.

Patients undergoing hypothermic cardiopulmonary bypass are often receiving aspirin therapy. Hypothermia, aspirin and cardiopulmonary bypass can each induce a platelet function defect, but it is not known if the effects of aspirin and hypothermia are additive in this regard. To address this question in humans in vivo, the forearm skin temperature of healthy volunteers was equilibrated and maintained at either normothermia (32 degrees C) or hypothermia (28 degrees C or 22 degrees C) before and 16 h after the ingestion of 650 mg aspirin. A standardized template bleeding time was performed on the forearm and the shed blood emerging from the wound was assayed for platelet surface P-selectin expression by whole blood flow cytometry (reflecting alpha granule secretion) and thromboxane B2 (the stable metabolite of thromboxane A2) by radioimmunoassay. Hypothermia resulted in marked prolongation of the bleeding time. Aspirin resulted in prolongation of the bleeding time under normothermic conditions, but only minimally augmented the hypothermia-induced prolongation of the bleeding time. Platelet surface P-selectin up-regulation in shed blood was abolished by hypothermia. Aspirin had no effect on maximal platelet surface P-selectin expression under normothermic or hypothermic conditions. Both hypothermia and aspirin resulted in markedly reduced shed blood thromboxane B2. Although aspirin slightly augmented the hypothermia-induced reduction in shed blood thromboxane B2, the concentration of thromboxane generated in shed blood under hypothermic conditions in the absence of aspirin had no effect on platelet surface P-selectin or platelet aggregation in whole blood. In conclusion, as determined by three independent parameters of the shed blood emerging from a standardized bleeding time wound (bleeding time, platelet surface P-selectin, and thromboxane B2), aspirin did not significantly augment hypothermia-induced platelet dysfunction in vivo.

Multi-hop forwarding extends wireless coverage and provides inexpensive Internet access. However, due to co-existing intra-path and inter-path interference in wireless networks, multi-hop forwarding significantly degrades network performance e.g. throughput, reliability and fairness etc.. In response to this challenge, we propose a unique solution, hybrid TDMA/CSMA, as a medium access control method to effectively handle a wide range of complicated interference scenarios under the impact of dynamic traffic. Our simulation results demonstrate that hybrid TDMA/CSMA significantly reduces packet loss rate, and increases throughput as well as fairness.

In mobile networks, node movements may lead to a situation called network partition where an end-to-end path may never exist because the network is divided into several isolated subnetworks. Deploying stationary relays introduces new transmission opportunities leading to the improvement of network connectivity and performance. The majority of the proposed solutions concentrated on deploying the minimum number of relays in the network. However, relay deployment should also be resilient regarding relay node failures. In this paper, we show how the relay deployment problem can be modelled as a k-element connectivity problem in which multiple relay-disjoint paths are deployed to connect isolated subnetworks. To solve this problem, we present three heuristic algorithms targeting at finding the minimum number of relays to form k-element connected networks. Our experiments using synthetic and real data showed that the proposed greedy algorithm is 2 or 3 orders of magnitude faster and never worse than the other two algorithms.

Heparin, a polyanionic glycosaminoglycan, is used routinely before the induction of cardiopulmonary bypass. Earlier observations in our laboratory suggested that the postoperative bleeding that occurs, despite neutralization of heparin with protamine, is secondary to hypothermia and dilutional anemia during bypass. An additional, potential mechanism for excessive bleeding following cardiopulmonary bypass is that heparin activates the fibrinolytic system, which may, in turn, adversely affect hemostasis. To understand better the effects of heparin administration on the fibrinolytic system in vivo, we simulated the anticoagulant regimen of cardiopulmonary bypass by administering increasing doses of intravenous heparin to five adult baboons over 60 min. We measured fibrinolytic parameters serially following heparinization and demonstrated that heparin induces activation of the fibrinolytic system. We showed that the fibrinolytic system was activated in vivo as evidenced by an increase in plasmin activity and immunoreactive plasmin light chain, as well as an increase in immunoreactive fibrinogen fragment E in vitro. These results demonstrate that the fibrinolytic system is activated in vivo by the administration of heparin during cardiopulmonary bypass. These data suggest that, despite administration of a neutralizing agent such as protamine, heparin may contribute to postoperative bleeding complications following cardiopulmonary bypass surgery owing principally to its longer lived effects on the fibrinolytic system.

Network tomography is the problem of discovering the delay and loss rate of the internal links of a network, assuming the internal nodes are not cooperating. The first step to solving this problem is finding network topology. Well-known tools such as trace route solve this problem, however they depend on cooperation of the internal nodes. This paper studies the problem of topology identification without relying on the cooperation of the internal nodes of the network. First, we suggest a novel probing scheme which is based on end-to-end unicast delay measurements. We then introduce a topology inference algorithm which uses the information from this probing scheme to find the topology of the network. Our experiments show that this approach improves the topology identification process compared to previous methods.

In this paper, we present Structured Message Transport (SMT). SMT is a transport protocol coordinator designed to alleviate the head-of-line blocking problem of existing transport layer protocols, such as TCP. SMT uses explicit dependency tracking instead of assuming total ordering between messages of a communication. Moreover, explicit dependency tracking creates the opportunity for using multiple paths. SMT can distribute messages into more than one path. However, unlike the stream-based Multi-Path-TCP, SMT is not limited to a single stream of messages. Relaxing the ordering constraints between the messages makes it possible to deliver the received messages to the application layer if they do not have any unmet dependencies. We have designed and implemented a prototype of SMT to test our ideas. Moreover, we have integrated the ideas from SMT into a proprietary software system and we show that the SMT version performs better than the base version.

In this paper, we report a simulation study of the scalability and performance of an optimal utility-based congestion control for a cluster-based router composed of commodity processors connected by a high-speed InfiniBand network. This control is optimal in the sense that it maximizes the sum of the utilities over ingress rates subject to an egress capacity constraint. We validate our simulation results by comparing them to experimental results from a small-scale prototype, and to the results from a fluid-flow model. One of the key aspects tested is the behaviour of the router's internal congestion control as a function of router size and varying traffic patterns. Our results show that the optimal scheme provides much smoother and tighter control than an AIMD-based control, thus leading to significantly higher throughput and lower delays. Our results also show that the optimal control scales well to large numbers of interfaces, and reacts quickly to changes in the input traffic intensity and pattern.

This prospective study was designed to determine whether use of nonwashed shed mediastinal blood exacerbated platelet and related hematologic dysfunctions after cardiopulmonary bypass, compared with the alternative use of autologous and homologous standard liquid preserved blood for volume support. Thirty-two patients undergoing cardiopulmonary bypass for open heart operations were randomized to receive either nonwashed shed mediastinal blood (group 1; n = 16) or liquid preserved packed red blood cells (group 2; n = 16) for transfusion therapy in the management of postoperative bleeding. Patient blood samples and bleeding times were obtained preoperatively, after cardiopulmonary bypass but before transfusions, 2 and 24 hours after transfusion, and on postoperative days 2, 3, and 7. Group 1 patients received an average of 710 +/- 90 mL (range, 300 to 1,700 mL) of nonwashed shed mediastinal blood containing significantly greater (p < 0.0001) amounts of fibrin degradation products and D-dimer protein. Of the hematologic, microaggregate, and plasma protein measurements performed, only the protein C level was significantly greater in group 1 (p < 0.05) after transfusion. Patient bleeding times were not significantly different between the groups at any of the time points, and the total postoperative blood loss was not different between the groups. There was a trend toward less need for homologous transfusion in group 1 (p < 0.1). This study documents the safety and ease of using nonwashed shed mediastinal blood as a primary blood volume support after an open heart operation.

Resource competition is inevitable in shared-resource systems, as the number of users increases or their resource demands change. In wireless networks, this problem is aggravated due to the existence of co-channel interference. Without appropriate control, harmful competition causes unbalanced user consumption of resources (e.g. starvation), and resource waste due to conflicts and idleness. In this paper we propose a novel framework to effectively manage resources (e.g. shared wireless channels). Compared with the state-of-art global optimization algorithm, our method is superior in terms of eliminating control overhead caused by message passing, achieving competitive performance, and reducing computational complexity. This framework combines the advantages of global and local optimization methods and drives the system toward a global optimum by intelligently exploiting local information.

An incomplete major pulmonary fissure can make anatomic lung resection technically more difficult and may increase the risk of complications, such as prolonged postoperative air leak. The objective of this study was to determine if preoperative computed tomography (CT) of the chest could accurately predict the completeness of the major pulmonary fissure observed at the time of surgery.From October 2008 to June 2009, patients at a single university institution were enrolled if they underwent surgery for a pulmonary nodule, mass or known cancer. At the time of surgery, completeness of the major pulmonary fissure was graded 1 if pulmonary lobes were entirely separate, 2 if the visceral cleft was complete with an exposed pulmonary artery at the base with some parenchyma fusion, 3 if the visceral cleft was only evident for part of the fissure without a visible pulmonary artery and 4 if the fissure was absent. The preoperative CT scan of each patient was graded by a single, blinded chest radiologist using the same scale. We used the Pearson χ2 test with 2-tailed significance to test the independence of the operative and radiologic grading.In 48% (29 of 61) of patients, the radiologic and operative grading were the same. Of those graded differently, 94% (30 of 32) were within 1 grade. Despite this agreement, we observed no statistically significant correlation between the operative and radiologic grading (p = 0.24).The major fissure can often be well-visualized on a preoperative CT scan, but preoperative CT cannot accurately predict the completeness of the major pulmonary fissure discovered at surgery.

The relocation of live, running virtual machines from one physical host to another is a new and very desirable function because it provides a variety of features, including resilience to failures and flexibility of location. The data transfers required for live migration are supported in several commercial products by a protocol called iSCSI (Internet SCSI), which runs on top of TCP. We thoroughly tested the performance of a common open source component, the Open-iSCSI initiator, and found a drastic throughput degradation on 100 Mbps networks where the round trip time was more than about 40 ms. We localized the problem to the TCP send buffer size and tested two methods of setting the TCP send buffer size appropriately. Based on our results, we propose a performance tuning scheme that enables users of Open-iSCSI to achieve significant throughput gains. Our scheme results in a dramatic throughput jump from 14 Mbps to 70 Mbps on a 100 Mbps link with an RTT of 100 ms. We also modified one of the data structures internal to Open-iSCSI to handle multiple memory pages in a single scatter/gather list entry. This modification resulted in an additional 20% throughput increase on a 100 Mbps link with an RTT of 200 ms.

In this paper we extend weighted max-min fairness by adding strategies that enable users to modify their fair allocation by sharing and borrowing bandwidth with other users. There is also a mechanism to reclaim bandwidth a user has previously shared. The main focus of our investigation is to develop a method for allocating link bandwidth between multiple users on multiple links of a communication network in the face of changing demands, usage patterns, and priorities while still being guided by max-min allocation. The algorithm is generic and could be applied to settings other than data networks such as process scheduling in operating systems, etc. We have tested the feasibility and performance of the algorithm via simulation. We have also integrated it into a commercial product and tested it in a real-world setting. We present the results from both types of tests in this paper.

The major hurdle for three-dimensional display of lung lobes is the automatic recognition of lobar fissures, boundaries of lung lobes. Lobar fissures are difficult to recognize due to their variable shape and appearance, along with the low contrast and high noise inherent in computed tomographic (CT) images. An algorithm for recognizing the major fissures in human lungs was developed and tested. The algorithm employs texture analysis and fissure appearance to mimic the way that surgeons/radiologists read CT images in clinical settings. The algorithm uses 3 stages to automatically find the major fissures in human lungs: (a) texture analysis, (b) fissure region analysis, and (c) fissure identification. The algorithm’s feasibility was evaluated using isotropic CT images from 16 anonymous patients with varying pathologies. Compared with manual segmentation, the algorithm yielded mean distances of 1.92 ± 2.07 and 2.07 ± 2.37 mm, for recognizing the left and right major fissures, respectively. An automatic recognition algorithm for major fissures in human lungs is feasible, providing a foundation for the future development of a complete segmentation algorithm for lung lobes.

Wireless sensor networks consist of a distributed set of sensor nodes that cooperatively monitor physical or environmental conditions, and send their data to a “sink” node over multihop wireless links. Since the main constraint in wireless sensor networks is limited energy supply at the sensor nodes, it is important to deploy the sink at a position with respect to the area of interest, a specific area that is of more interest to the end-user, such that total energy consumption is minimized. In this paper we propose a new dynamic approach to find the optimal position for the sink with the goal of reducing the total energy consumption which has a direct effect on the network’s lifetime. A related problem is that the nodes neighboring the sink suffer more rapid energy depletion due to high transit traffic. This situation can be mitigated by relocating the sink occasionally. In this work we propose an algorithm based on exhaustive search to find the initial optimal sink location, and to relocate the sink when appropriate. This exhaustive search is intended as a standard by which other more efficient and practically useful algorithms can be judged. We also investigate the effects of various additional constraints on the solutions from exhaustive search.

The use of cardiopulmonary bypass (CPB) during cardiac surgery is associated with a hemostatic defect, the hallmark of which is a markedly prolonged bleeding time. However, the nature of the putative platelet function defect is controversial. In this study, blood was analyzed at 10 time points before, during, and after CPB. We used a whole-blood flow cytometric assay to study platelet surface glycoproteins in (1) peripheral blood, (2) peripheral blood activated in vitro by either phorbol myristate acetate, the thromboxane (TX)A2 analog U46619, or a combination of adenosine diphosphate and epinephrine, and (3) the blood emerging from a bleeding-time wound (shed blood). Activation-dependent changes were detected by monoclonal antibodies directed against the glycoprotein (GP)Ib-IX and GPIIb-IIIa complexes and P-selectin. In addition, we measured plasma glycocalicin (a proteolytic fragment of GPIb) and shed-blood TXB2 (a stable breakdown product of TXA2). In shed blood emerging from a bleeding-time wound, the usual time-dependent increase in platelet surface P-selectin was absent during CPB, but returned to normal within 2 hours. This abnormality paralleled both the CPB-induced prolongation of the bleeding time and a CPB-induced marked reduction in shed-blood TXB2 generation. In contrast, there was no loss of platelet reactivity to in vitro agonists during or after CPB. In peripheral blood, platelet surface P-selectin was negligible at every time point, demonstrating that CPB resulted in a minimal number of circulating degranulated platelets. CPB did not change the platelet surface expression of GPIb in peripheral blood, as determined by the platelet binding of a panel of monoclonal antibodies, ristocetin-induced binding of von Willebrand factor, and a lack of increase in plasma glycocalicin. CPB did not change the platelet surface expression of the GPIIb-IIIa complex in peripheral blood, as determined by the platelet binding of fibrinogen and a panel of monoclonal antibodies. In summary, CPB resulted in (1) markedly deficient platelet reactivity in response to an in vivo wound, (2) normal platelet reactivity in vitro, (3) no loss of the platelet surface GPIb-IX and GPIIb-IIIa complexes, and (4) a minimal number of circulating degranulated platelets. These data suggest that the “platelet function defect” of CPB is not a defect intrinsic to the platelet, but is an extrinsic defect such as an in vivo lack of availability of platelet agonists. The near universal use of heparin during CPB is likely to contribute substantially to this defect via its inhibition of thrombin, the preeminent platelet activator.

Allocating wireless network resources fairly to users, and using these limited resources efficiently is crucial for improving system performance and satisfying user requirements. Our proposal is to achieve higher network throughput via lower transmit power, and to reduce throughput differences between flows caused by uncontrolled resource competition. A hierarchical joint control framework has been designed to achieve this goal. The performance of this framework has been evaluated via ns2 simulation. Our experimental results demonstrate that our control framework significantly improves performance and results in lower packet loss rates, higher network throughput, shorter end-to-end delay and enhanced fairness.

The detection of malicious executables (malware) is a well known problem. Anti-malware software are typically signature based, and only malicious attacks containing those known signatures can be detected. This is problematic because new malware is appearing extremely rapidly. This threatens to overwhelm signature-based approaches. In this paper, we propose a novel approach to detect malicious executables by using a combination of techniques from bioinformatics, data mining and information retrieval. This method is able to identify new malware related to threats already in its database. Using relatively small training sets our technique is able to achieve over 90% accuracy of detection with a false positive rate smaller than 5%.

Long-haul traffic accounts for a large percentage of the total data carried on the Internet. Due to the rapid changes of the Internet in terms of access technologies and core network bandwidth, the performance of long-haul transmission in the current Internet environment has not been well understood. In our research, we chose three typical long-haul paths (national, international yet continental, international and intercontinental) and studied their performance under a variety of access rates: dial-up, ADSL, ADSL2, and best-effort. Our results show that as long as the paths are within one continent, the long-haul transmission will be very reliable. However, intercontinental transmission suffers seriously from bandwidth fluctuation and packet retransmission.

In shared-medium wireless networks, nodes contend for medium access in space, time and channel bandwidth. Uncontrolled competition for limited network resources causes severe packet collisions and compounds network congestion. Consequently, data transmission is subject to very long delay, significant packet loss and poor throughput. This work focuses on improving data transmission in wireless ad hoc networks through optimal control of spatial, temporal and bandwidth contention. Our simulation study demonstrates that this optimal control scheme outperforms RTS/CTS and achieves significant improvement of CSMA/CA performance under various effects.

Inefficient resource management may cause problems of reliability of service in shared medium wireless networks. Resources include bandwidth, processor cycles and buffers. Excessive competition for these resources can cause severe packet collision rates, compound network congestion, or even result in starvation of some nodes. In such a situation, data transmission is subject to very long delays and significant packet losses. Although transport layer protocols can help improve end-to-end performance, these approaches are slow in responding to network changes and incur additional overhead. This paper aims to reduce transmission delay and increase packet delivery ratio. A hybrid resource allocation problem is formulated by the Primal algorithm and a controller is derived to decrease congestion globally and to reduce collisions locally. Our simulation results show that this hybrid controller can achieve packet loss rates close to 1% and significantly shorten end-to-end delay even in a high interference environment with heavy system load. In addition, we also compare the performance of the hybrid controller with the impact of multipath routing. The accuracy of our simulation is improved by adding a probabilistic preamble detection model and SINR collision model based on frame error rate.