Ad Hoc Mesh Network Localization Using Ultra-Wideband for Mobile Robotics.

This article explores the implementation of high-accuracy GPS-denied ad hoc localization. Little research exists on ad hoc ultra-wideband-enabled localization systems with mobile and stationary nodes. This work aims to demonstrate the localization of bicycle-modeled robots in a non-static environment through a mesh network of mobile, stationary robots, and ultra-wideband sensors. The non-static environment adds a layer of complexity when actors can enter and exit the node's field of view. The method starts with an initial localization step where each unmanned ground vehicle (UGV) uses the surrounding, available anchors to derive an initial local or, if possible, global position estimate. The initial localization uses a simplified implementation of the iterative multi-iteration ad hoc localization system (AHLos). This estimate was refined using an unscented Kalman filter (UKF) following a constant turn rate and velocity magnitude model (CTRV). The UKF then fuses the robot's odometry and the range measurements from the Decawave ultra-wideband receivers stationed on the network nodes. Through this position estimation stage, the robot broadcasts its estimated position to its neighbors to help the others further improve their localization estimates and localize themselves. This wave-like cycle of nodes helping to localize each other allows the network to act as a mobile ad hoc localization network.

An unusual presentation of metastatic esophageal adenocarcinoma presenting as thigh pain.

The association between esophageal adenocarcinoma and distant skeletal muscle metastasis is extremely rare. Only three cases have been previously reported in the literature. All reported involvement of the gastroesophageal junction. We describe a 58 year-old Caucasian man who presented with worsening right hip pain for nine months. Computerized axial tomography (CT) scan demonstrated a 10 cm by 8 cm by 12 cm intra-pelvic mass involving the right iliacus muscle with central destruction of the right mid-ileum. CT-guided biopsy of the right hip mass demonstrated poorly differentiated carcinoma. CT scan of the chest revealed a 5 cm by 4 cm circumferential mass involving the distal esophagus. Endoscopic biopsy showed poorly differentiated adenocarcinoma. Immunohistochemical analysis of each specimen correlated for pancytokeratin. Final diagnosis was primary esophageal adenocarcinoma with distant metastasis to the right ileum and iliacus muscle. We review distinctions between esophageal adenocarcinoma and adenocarcinoma of the gastroesophageal junction. A brief discussion of diagnostic modalities and treatment options are provided.

An unusual presentation of primary sclerosing cholangitis.

This case report describes the unusual presentation of a patient who had findings which were initially suggestive of a type IV choledochal cyst. Her liver biopsy demonstrated biliary cirrhosis. She was treated with endoscopic retrograde cholangiopancreatography and biliary stent exchanges over one year. Her cholangiogram one year later demonstrated resolution of the biliary cystic dilation which led to her initial diagnosis, with beading and stricturing of the hepatic ducts consistent with primary sclerosing cholangitis. Liver-associated enzymes and physical findings also improved. A liver biopsy one year later demonstrated a marked improvement in hepatic fibrosis with no evidence of cirrhosis.

Drug-induced liver injury in 2007.

PURPOSE OF REVIEW: To summarize the pertinent literature on the causes, epidemiology, prevalence, clinical features, evaluation and mechanisms of drug-induced liver injury reported during 2007. RECENT FINDINGS: Although the frequency of drug-induced liver injury remains low, new data from the Centers for Disease Control and Prevention confirm that of the approximately 1600 new acute liver failure cases annually, acetaminophen hepatotoxicity accounts for 41%; among children with acute liver failure, acetaminophen was the second most common cause. Antimicrobials lead the list of non-acetaminophen causes of drug-induced liver injury. In Asia, herbal compounds are the most common causes of the condition. Pravastatin was shown to be safe in patients with nonalcoholic fatty liver disease or chronic hepatitis C. The US Food and Drug Administration issued a draft guidance document on the premarketing clinical evaluation and stopping rules of drug-induced liver injury signals, including Hy's Law cases in clinical trials. SUMMARY: The year 2007 brought with it several reminders of the importance of drug-induced liver injury in the clinical trial as well as the clinical practice setting. There is additional evidence that statin drugs may be used safely in patients with chronic liver disease. Comments received by the US Food and Drug Administration to finalize their guidance document are eagerly awaited.

Integrated assessment modeling of atmospheric pollutants in the Southern Appalachian Mountains. Part I: hourly and seasonal ozone.

Recently, a comprehensive air quality modeling system was developed as part of the Southern Appalachians Mountains Initiative (SAMI) with the ability to simulate meteorology, emissions, ozone, size- and composition-resolved particulate matter, and pollutant deposition fluxes. As part of SAMI, the RAMS/EMS-95/URM-1ATM modeling system was used to evaluate potential emission control strategies to reduce atmospheric pollutant levels at Class I areas located in the Southern Appalachians Mountains. This article discusses the details of the ozone model performance and the methodology that was used to scale discrete episodic pollutant levels to seasonal and annual averages. The daily mean normalized bias and error for 1-hr and 8-hr ozone were within U.S. Environment Protection Agency guidance criteria for urban-scale modeling. The model typically showed a systematic overestimation for low ozone levels and an underestimation for high levels. Because SAMI was primarily interested in simulating the growing season ozone levels in Class I areas, daily and seasonal cumulative ozone exposure, as characterized by the W126 index, were also evaluated. The daily ozone W126 performance was not as good as the hourly ozone performance; however, the seasonal ozone W126 scaled up from daily values was within 17% of the observations at two typical Class I areas of the SAMI region. The overall ozone performance of the model was deemed acceptable for the purposes of SAMI's assessment.

Acute hepatic sequestration in sickle cell disease.

Sickle cell anemia is a disease that affects one out of every 600 African Americans. It is often debilitating and can cause many physical restrictions to individuals with the disease. The disease has many complications which can be vexing for patients and their physicians. The hepatic complications attributed to vascular occlusion encompass a variety of clinical syndromes of which the relationship among clinical presentation, biochemical findings, and histologic features remains unclear. The conditions range from the self-limiting hepatic right upper quadrant syndrome (hepatic crisis) to the potentially lethal intrahepatic cholestasis and acute hepatic sequestration syndromes. Few cases have been documented, and there have not been many sizable studies on acute hepatic sequestration in sickle cell disease. This case is useful for clinicians who are not familiar with the intrahepatic vaso-occlusive syndromes in sickle cell disease. It provides insight into the presentation, diagnosis, and management of these syndromes.

Evaluating performance of law enforcement personnel during a stressful training scenario.

Police trainees who were ready to graduate from the Federal Law Enforcement Training Center (FLETC) volunteered to participate in an exercise designed to evaluate their survivability. In a highly stressful interactive scenario, which included a hostage situation, performance was evaluated for a range of responses, including: shooting judgment and accuracy, communications, and coping with a weapon malfunction. Nineteen percent of subjects shot the hostage, a failure rate that falls in the reported range of friendly fire casualties in military combat. The Spielberger Trait Anger Scale showed an association with shot placement and performance during the gunfight as well as with overall performance scores.

The use of local anaesthesia in peripheral venous cannulation: current practice of junior doctors.

OBJECTIVE: To determine the rate of use of local anaesthetic in peripheral venous cannulation by pre-registration house officers and to determine reasons why they do not use it. DESIGN: Analysis of anonymous questionnaires distributed to pre-registration house officers at scheduled weekly education meetings. SETTING: One regional hospital and three district general hospitals in the United Kingdom. RESULTS: 71 questionnaires were distributed directly to respondents and subsequently analysed. 46 respondents (65%) stated that they never used local anaesthetic for peripheral venous cannulation. Of those who used local anaesthetic the average rate of use was 6%. Of those who used local anaesthetic 48% stated they used EMLA and 84% stated they used lignocaine. 4% stated they would use local anaesthetic for 22 gauge cannulae, 8% would use it for 20 gauge, 24% for 18 gauge and 40% for 16 gauge and 28% for 14 gauge cannulae. 45% stated that using local anaesthetic was too time consuming, 35% stated it was not indicated, 21% stated that it made cannulation difficult, 13% stated that local anaesthetic was not available on the ward, 13% stated that it was logistically difficult, 4% stated that there was peer pressure not to use it, 4% stated they were not allowed to use local anaesthetic and 3% stated that it was practically difficult. 20% of respondents gave no reason. CONCLUSIONS: Despite good clinical evidence that the pain of peripheral venous cannulation can be successfully obviated using local anaesthetic, the rate of use by pre-registration house officers is low. It is suggested that during formal cannulation training, more emphasis be placed on the provision of analgesia. This should aim to increase the quality of care to those patients requiring intravenous cannulation as well as offering other potential benefits to doctors.

Attitudes to smoking on submarines: results of a questionnaire study.

An anonymous survey to assess the attitudes to smoking of men serving on two Trident Nuclear submarines was conducted by questionnaire. A total of 244 questionnaires were completed, representing 87% of the two crews. Thirty-two percent of respondents declared themselves to be smokers, 69% were nonsmokers, and of these, 31% were ex-smokers. Attitudes of all respondents to an enforced ban of smoking on submarines indicated that 55% felt that it would be justifiable, 46% felt that it would be unfair, 42% felt that it was uncalled for, 46% thought that it would be illegal, and 47% thought that a ban was about time. The separate opinions of smokers and nonsmokers were polarized, whereas the overall results indicate indifferent attitudes of crew members. Further research into the atmospheric effects of environmental tobacco smoke on a submarine is required.