New Positive Inotropic Agents

Current therapy for heart failure remains inadequate. New positive inotropic agents that augment myocardial contractility have been introduced. The positive inotropic effects of these nonglycoside, nonsympathomimetic agents are due, at least in part, to inhibition of cardiac phosphodiesterase activity and hence to an increase in myocardial cyclic AMP levels. These agents also have vasodilator properties through their effects on the enzyme phosphodiesterase in the vascular smooth muscle. Recent developments in the preclinical pharmacology, mechanism of action, and clinical experience with these new inotrope vasodilators are presented in this review. The role these drugs will play in revising our therapeutic strategy in congestive heart failure remains to be defined

Modeling of impact dynamics of tennis ball with a flat surface

A two-mass model with a spring and a damper in the vertical direction, accounting for vertical translational motion and a torsional spring and a damper connecting the rotational motion of two masses is used to simulate the dynamics of a tennis ball as it comes into contact with a flat surface. The model is supposed to behave as a rigid body in the horizontal direction. The model is used to predict contact of the ball with the ground and applies from start of contact to end of contact. The springs and dampers for both the vertical and the rotational direction are linear. Differential equations of motion for the two-mass system are formulated in a plane. Two scenarios of contact are considered: Slip and no-slip. In the slip case, Coulomb??s law relates the tangential contact force acting on the outer mass with the normal contact force, whereas in the no-slip case, a kinematic constraint relates the horizontal coordinate of the center of mass of the system with the rotational coordinate of the outer mass. Incorporating these constraints in the differential equations of motion and applying initial conditions, the equations are solved for kinematics and kinetics of these two different scenarios by application of the methods for the solutions of second-order linear differential equations. Experimental data for incidence and rebound kinematics of the tennis ball with incidence zero spin, topspin and backspin is available. The incidence angles in the data range from 17 degrees up to 70 degrees. Simulations using the developed equations are performed and for some specific ratios of inner and outer mass and mass moments of inertia, along with the spring-damper coefficients, theoretical predictions for the kinematics of rebound agree well with the experimental data. In many cases of incidence, the simulations predict transition from sliding to rolling during the contact, which is in accordance with the results obtained from available experimental measurements conducted on tennis balls. Thus the two-mass model provides a satisfactory approximation of the tennis ball dynamics during contact

A multicenter evaluation of the diagnosis, management and outcomes of adenovirus enteritis infection following intestine or multivisceral transplant

Introduction: Adenovirus Enteritis (AE) is a unique infection which can complicate patient course following intestine and multivisceral transplantation. Solid organ transplant patients have an increased risk for infection and intestine and multivisceral patients are unique in that they often develop inflammation from rejection in the intestine which might predispose to infection. Methods: We reviewed patients who received an intestine transplant at three academic transplant centers between 2010 and 2020 for demographic, laboratory and clinical data. Results: Five patients were identified with diagnosis of adenovirus enteritis. Three patients (60%) had isolated intestine transplant while two underwent multivisceral transplantation. Reason for transplant included trauma, volvulus, intestinal atresia and visceral neuropathy. All patients received induction with anti-thymocyte globulin (80%) or basiliximab. The initial diagnosis of infection occurred at a mean of 26.8 months following transplant (range 2-68 months). Diagnosis was by polymerase chain reaction (PCR) measurement in plasma (80%), intestine or stool. Cidofovir was used in 100% of cases as primary management. 40% of patients had reduction of immunosuppression at the time of diagnosis while the remainder did not. 60% of patients had rejection within a month prior to diagnosis. No patients had recurrent rejection in the month following treatment. Two patients had recurrent infection. No patients had graft loss or death within 6 months of infection. Two patients had enterectomy at a mean of 29.5 months after infection (range 22-37 months) Three patients died at a mean of 32 months following diagnosis (range 8-51 months). Conclusion: We present a series of five cases of adult patients with AE following intestinal and multivisceral transplant. AE may arise due to immunosuppression, vascular compromise of the transplanted organ, or a combination of factors. Our study supported rejection as a risk factor for infection. Graft loss or death was not seen within 6 months following infection

A Novel Optimization of the Distance Source Routing (DSR) Protocol for the Mobile Ad Hoc Networks (MANET)

The final publication is available at www.springerlink.comThis paper presents a new scheme for the Distance Source Routing (DSR) protocol which shows the improvement over the two major metrics of the DSR protocol: Route Discovery and Route Maintenance. In addition, we present a mathematical model that includes probability density function for these two observed metrics. Our simulation results demonstrate a significant improvement in the route discovery, transmission time, and the overall network utilization. As an interesting side result, our analysis also shows that the proposed model can be used to effectively reduce the packet losses.http://link.springer.com/chapter/10.1007%2F978-90-481-3662-9_4

Altered Platelet Function in Patients with Severe Congestive Heart Failure

Platelet function was assessed in 15 patients with severe congestive heart failure (CHF) and in 26 control subjects of similar ages. The platelet count (mm3), surface reactivity, aggregometry studies, release factors, and circulating aggregates were investigated. The mean number of circulating platelets was normal, but a hyperactive platelet response was found in 53% of the CHF patients. CHF patients had a 42% mean for the spread type platelet, and the average number of aggregates was 64: control subjects had a 12% mean for the spread type platelet, and the average number of aggregates was 40 (p \u3c 0.05). Aggregation with all of the inducers was normal, although 27% of CHF patients showed spontaneous aggregation. The mean plasma levels of both platelet factor 4 and betathromboglobulin were abnormally elevated. No circulating platelet aggregates were detected. Our studies indicate that platelet function is abnormal in patients with CHF. The abnormal platelet reactivity found might contribute to the increased incidence of thromboembolic events observed in CHF patients

Hepatitis C Cirrhosis, Hepatitis B Superimposed Infection, and the Emergence of an Acute Portal Vein Thrombosis: A Case Report

Acute portal vein thrombosis (PVT) is a complication of liver cirrhosis. The presence of viral infections such as hepatitis B (HBV) and hepatitis C (HCV) can further increase cirrhotic patients\u27 risk of developing PVT, especially in the rare case when there is superinfection with both HBV and HCV. We present a patient with HCV cirrhosis whose clinical condition was decompensated secondary to the development of superimposed HBV infection, who developed acute PVT during hospitalization. This case offers a unique presentation of acute PVT that developed within several days of hospitalization for decompensated liver disease, as proven by the interval absence of portal venous flow on repeat imaging. Despite the workup on the initial presentation being negative for PVT, reconsideration of differentials after the change in our patient\u27s clinical status led to the diagnosis. Active HBV infection was likely the initial trigger for the patient\u27s cirrhosis decompensation and presentation; the subsequent coagulopathy and alteration in the portal blood flow triggered the development of an acute PVT. The risk for both prothrombotic and antithrombotic complications remains high in patients with cirrhosis, a risk that is vastly increased by the presence of superimposedinfections. The diagnosis of thrombotic complications such as PVT can be challenging, thus stressing the importance of repeat imaging in instances where clinical suspicion remains high despite negative imaging. Anticoagulation should be considered for cirrhotic patients with PVT on an individual basis for both prevention and treatment. Prompt diagnosis, early intervention, and close monitoring of patients with PVT are crucial for improving clinical outcomes. The goal of this report is to illustrate diagnostic challenges that accompany the diagnosis of acute PVT in cirrhosis, as well as discuss therapeutic options for optimal management of this condition

Yield of esophagogastroduodenoscopy and colonoscopy in cancer of unknown primary

Objectives: Carcinoma of unknown primary origin (CUP) is heterogeneous group of cancers. Role of gastrointestinal (GI) endoscopy in this entity is under investigated. Aim of this study was to evaluate yield of Colonoscopy and Esophagogastroduodenoscopy (EGD) in localizing primary tumor in patients with CUP. METHODOLOGY: Patients with histopathologically proven CUP who underwent colonoscopy / EGD to find the primary tumor from December 2009 to December 2011 were included in the study. Abdominal symptoms and cytokeratin (CK) 7 and 20 markers were correlated with presence of primary in GI tract. Results: After giving informed consent 86 patients were included in final analysis. All patients underwent colonoscopy while 60(70%) got EGD along with colonoscopy. Mean age was 55.10 +/-11.94 years with 52(60%) male. Abdominal symptoms were present in 50%. CK7+/CK20- in 34(40%); CK7-/CK20+ in 2(2%) while CK7+/20+ in 7(8%) of metastatic tumor samples. Liver was metastatic site in 47(55%), Lymph node 12(14%) and Ascites in 8(9%). Endoscopy detected primary in 6 (7%) patients with 3 each in stomach and colon. No association of abdominal symptoms and cytokeratin markers was found with presence of GI primary site. CONCLUSION: Yield of localizing primary lesion in the GI tract by pan-endoscopy was limited. Abdominal symptoms and cytokeratin markers do not predict presence of gastrointestinal malignancies

Refresh Triggered Computation: Improving the Energy Efficiency of Convolutional Neural Network Accelerators

To employ a Convolutional Neural Network (CNN) in an energy-constrained embedded system, it is critical for the CNN implementation to be highly energy efficient. Many recent studies propose CNN accelerator architectures with custom computation units that try to improve energy-efficiency and performance of CNNs by minimizing data transfers from DRAM-based main memory. However, in these architectures, DRAM is still responsible for half of the overall energy consumption of the system, on average. A key factor of the high energy consumption of DRAM is the refresh overhead, which is estimated to consume 40% of the total DRAM energy. In this paper, we propose a new mechanism, Refresh Triggered Computation (RTC), that exploits the memory access patterns of CNN applications to reduce the number of refresh operations. We propose three RTC designs (min-RTC, mid-RTC, and full-RTC), each of which requires a different level of aggressiveness in terms of customization to the DRAM subsystem. All of our designs have small overhead. Even the most aggressive RTC design (i.e., full-RTC) imposes an area overhead of only 0.18% in a 16 Gb DRAM chip and can have less overhead for denser chips. Our experimental evaluation on six well-known CNNs show that RTC reduces average DRAM energy consumption by 24.4% and 61.3%, for the least aggressive and the most aggressive RTC implementations, respectively. Besides CNNs, we also evaluate our RTC mechanism on three workloads from other domains. We show that RTC saves 31.9% and 16.9% DRAM energy for Face Recognition and Bayesian Confidence Propagation Neural Network (BCPNN), respectively. We believe RTC can be applied to other applications whose memory access patterns remain predictable for a sufficiently long time

RSV associated hospitalizations in children in Karachi, Pakistan: Implications for vaccine prevention strategies

Major progress is being made in vaccines against Respiratory Syncytial Virus (RSV), with multiple vaccine candidates currently in the clinical phase of development. Making an investment case for public sector financing of RSV vaccine will require estimation of burden, cost-effectiveness, and impact. The aim of this study is to determine the proportion, age distribution and clinical spectrum of RSV associated hospitalizations in children in Karachi, Pakistan. A three years prospective study was conducted at the Aga Khan University Hospital in Karachi, a city of 20 million in south Pakistan, from August 2009 to June 2012. Children less than five years old admitted with acute respiratory infections (ARI) were enrolled. Throat swabs were collected and tested for RSV using real-time PCR. Multivariable log binomial regression analysis was performed to identify the associated factors of RSV infection. Out of 1150 children enrolled, RSV was detected among 223 (19%). Highest rate of RSV detection was in young infants less than 3 months of age (48/168, 29%), which accounted for 22% of all RSV detected. Most common diagnosis in RSV positive infants (age) was bronchiolitis followed by pneumonia, while in older children between the ages of one and 5 years of age, pneumonia and asthma were the most common diagnosis. Although identified year-round, RSV was most prevalent from August to October with peak in September, coinciding with the rainy season. This study identified RSV to be independently associated with younger age (P = 0.036), rainy season (P \u3c 0.001), post-tussive emesis (P = 0.008), intubation (P = 0.003), and discharge diagnosis of bronchiolitis (P = 0.004). Vaccines against RSV that target this age group are likely to yield remarkable benefit