Sidelobe Suppression Techniques for Near-Field Multistatic SAR.

Multirotor Unmanned Air Systems (UAS) represent a significant improvement in capability for Synthetic Aperture Radar (SAR) imaging when compared to traditional, fixed-wing, platforms. In particular, a swarm of UAS can generate significant measurement diversity through variation of spatial and frequency collections across an array of sensors. In such imaging schemes, the image formation step is challenging due to strong extended sidelobe; however, were this to be effectively managed, a dramatic increase in image quality is theoretically possible. Since 2015, QinetiQ have developed the RIBI system, which uses multiple UAS to perform short-range multistatic collections, and this requires novel near-field processing to mitigate the high sidelobes observed and form actionable imagery. This paper applies a number of algorithms to assess image reconstruction of simulated near-field multistatic SAR with an aim to suppress sidelobes observed in the RIBI system, investigating techniques including traditional SAR processing, regularised linear regression, compressive sensing. In these simulations presented, Elastic net, Orthogonal Matched Pursuit, and Iterative Hard Thresholding all show the ability to suppress sidelobes while preserving accuracy of scatterer RCS. This has also lead to a novel processing approach for reconstructing SAR images based on the observed Elastic net and Iterative Hard Thresholding performance, mitigating weaknesses to generate an improved combined approach. The relative strengths and weaknesses of the algorithms are discussed, as well as their application to more complex real-world imagery.

Early posttraumatic ankle osteoarthritis following ankle fracture-dislocations in a sub-Saharan African setting.

INTRODUCTION: Ankle fracture-dislocation (AFD) represents a major threat to the joint and a potential source of complication and functional disability. This study was performed to assess the outcome of AFD in a resource-limited setting and factors associated with the posttraumatic ankle osteoarthritis (PTAOA). We hypothesized that conservative treatment after AFD was associated with higher risk of PTAOA compared to surgical treatment. PATIENTS AND METHODS: Data from 52 consecutive patients (mean age 37.2±11.1years, with 57.7% n=30, males) who were treated and followed in a teaching hospital for AFD during a period of six years were collected. Forty-four of these patients were obtained at the time of the study for a retrospective evaluation. Functional outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS), ankle-hindfoot scale, and the patient's global satisfaction index. Radiographs were performed and analyzed for PTAOA. Logistic regression was used to determine factors associated with the presence of PTAOA. RESULTS: PTAOA was found in 19 (43.2%) patients after an average follow-up period of 27.2±18.3months. Anatomic fracture reduction was achieved in 22 (50%) patients, while the talus was centered in the mortise in 30 (68.2%) patients. Despite these poor anatomical results, the clinical outcome was good to excellent in 33 (75%) patients, and 88.6% was satisfied or very satisfied. Factors associated with the presence of PTAOA were the non-anatomical reduction (OR=11.07; p=0.007, 95% CI: 2.096-58.77) and the time elapsed since trauma (OR=1.073; p=0.007, 95% CI: 1.109-1.129). CONCLUSION: This study indicates that AFDs are associated with high rate of early and severe PTAOA. Non-anatomical realignment and a delay since trauma were positive predictors of PTAOA. There was no difference regarding the occurrence of PTAOA after AFD whatever the type of treatment, surgical or conservative. LEVEL OF EVIDENCE: IV; retrospective cohort study.

Androglobin gene expression patterns and FOXJ1-dependent regulation indicate its functional association with ciliogenesis.

Androglobin (ADGB) represents the latest addition to the globin superfamily in metazoans. The chimeric protein comprises a calpain domain and a unique circularly permutated globin domain. ADGB expression levels are most abundant in mammalian testis, but its cell-type-specific expression, regulation, and function have remained unexplored. Analyzing bulk and single-cell mRNA-Seq data from mammalian tissues, we found that-in addition to the testes-ADGB is prominently expressed in the female reproductive tract, lungs, and brain, specifically being associated with cell types forming motile cilia. Correlation analysis suggested coregulation of ADGB with FOXJ1, a crucial transcription factor of ciliogenesis. Investigating the transcriptional regulation of the ADGB gene, we characterized its promoter using epigenomic datasets, exogenous promoter-dependent luciferase assays, and CRISPR/dCas9-VPR-mediated activation approaches. Reporter gene assays revealed that FOXJ1 indeed substantially enhanced luciferase activity driven by the ADGB promoter. ChIP assays confirmed binding of FOXJ1 to the endogenous ADGB promoter region. We dissected the minimal sequence required for FOXJ1-dependent regulation and fine mapped the FOXJ1 binding site to two evolutionarily conserved regions within the ADGB promoter. FOXJ1 overexpression significantly increased endogenous ADGB mRNA levels in HEK293 and MCF-7 cells. Similar results were observed upon RFX2 overexpression, another key transcription factor in ciliogenesis. The complex transcriptional regulation of the ADGB locus was illustrated by identifying a distal enhancer, responsible for synergistic regulation by RFX2 and FOXJ1. Finally, cell culture studies indicated an ADGB-dependent increase in the number of ciliated cells upon overexpression of the full-length protein, confirming a ciliogenesis-associated role of ADGB in mammals.

North End Community Health Centre in Halifax, NS: Relationship-based care goes beyond collaborative care to address patient needs.

OBJECTIVE: To identify and describe features of relationship-based care that contribute to a successful collaborative model of primary care delivery. DESIGN: Focused institutional ethnography using a critical medical anthropology approach. SETTING: The North End Community Health Centre (NECHC) in downtown Halifax, NS. PARTICIPANTS: Twenty health care providers employed or previously employed at the NECHC. METHODS: Qualitative data collection included participant observation, recorded and transcribed semistructured interviews, informal discussions, and policy document analysis. Data collection continued until saturation was reached, between December 2014 and October 2016. Data were member checked, coded, and triangulated with evidence from policy documents and informal conversations to establish credibility. MAIN FINDINGS: The NECHC offers high-quality care to the community, welcoming marginalized, vulnerable populations. The NECHC's recognized success is grounded in unique relationships among providers, patients, and the community. Four key themes contributing to relationship-based care in the clinic's operation emerged: an activist provider identity, cultural safety, provider-patient relationships, and provider-provider relationships. Inadequate provincial funding mechanisms limit the work and development of the clinic. CONCLUSION: Collaborative care is advanced by health authorities to improve quality of care and reduce health care costs. This model is still poorly understood in Nova Scotia. The findings, which draw on focused ethnographic fieldwork and analysis of the NECHC, suggest that the NECHC is a pragmatic real-world model of collaborative health care. The success of its approach relies on a deliberative democratic realization of reflexive practice through relationship-based care.

Loss of Neuroglobin Expression Alters Cdkn1a/Cdk6-Expression Resulting in Increased Proliferation of Neural Stem Cells.

In the quest to unravel its functional significance, neuroglobin (Ngb), a brain-specific neuroprotective protein, has recently been proposed as an actor in neurodevelopment. As neural stem cells (NSCs) are fundamental during brain development, the present study aimed at investigating the role of Ngb in the growth and proliferation of NSCs by comparing an Ngb-floxed (Ngbfl-)NSC line, equivalent to the wild-type cellular situation, with an in-house created Ngb knockout (NgbKO-)NSC line. NgbKO-NSCs were characterized by an increased growth and proliferation capacity in vitro, supported by RNA sequencing and western blot results reporting the downregulation of Cdkn1a and the upregulation of Cdk6, both enhancing the cell cycle. Based on additional gene ontology enrichment and pathway analyses, we hypothesize that the loss of Ngb affects multiple cellular signaling pathways with the most important being the Akt-Tp53 axis.

Hearing Without Neuroglobin.

Neuroglobin (Ngb) is a member of the globin family of respiratory proteins, which was recently observed in many neurons of the auditory pathways. Up to now, however, nothing was known about the role of Ngb in hearing processes. We therefore studied auditory function by recording distortion-product otoacoustic emissions (DPOAE) and auditory brainstem responses (ABRs) in wild-type (C57BL/6N) and Ngb-knockout mice. In KO mice, DPOAE thresholds were moderately augmented in the range of 5-18 kHz, reaching statistical significance at 8 and 10 kHz, while the ABR thresholds were not different between groups. The activation of the efferent system by an additional noise given to the contralateral ear resulted in an increased f2-f1-emission level only in WT animals. A noise exposure resulted in similar acute threshold shifts in the DPOAE and ABR of both animal groups. The recovery of hearing function, expressed by decreased DPOAE thresholds, was not significantly different between groups after four days and after four weeks. ABR recordings showed that threshold shifts elicited by noise-trauma were slightly better revised in wild-type mice. While ABR amplitudes were similar in both groups before noise overexposure, four weeks after trauma a moderate but statistically significant decrease of the latest peak-to-peak response amplitude (originating in the inferior colliculus) was observed in KO mice. Our results suggest that the lack of Ngb, at least in the model used in the present study, results in only marginal deficits in hearing ability. A putative functional role of Ngb in the efferent system warrants further studies.

Efficacy and safety of extracorporeal shock wave lithotripsy for chronic pancreatitis.

INTRODUCTION: There is still uncertainty regarding the efficacy and optimal modalities of extracorporeal shock wave lithotripsy (ESWL) in the treatment of chronic pancreatitis. The aims of the present study were to assess the safety and the efficacy of ESWL, either alone or followed by therapeutic endoscopic retrograde cholangiopancreatography (adjuvant ERCP) and to determine predictive factors of efficacy, in a real-life setting. PATIENTS AND METHODS: This study included all consecutive patients who underwent an ESWL in a single University Hospital between 2001 and 2012. The indication for ESWL was obstructive stone(s) of the main pancreatic duct resulting in either painful chronic pancreatitis or recurrent acute pancreatitis. Success was defined by resolution of pain, no analgesic treatment, no acute pancreatitis and no surgical treatment for chronic pancreatitis 6 months after the ESWL. RESULTS: One hundred and forty-six patients were studied; 6/146 (4%) had a complication of ESWL. Among the 132 patients in whom follow-up was completed, 91 (69%) had an adjuvant ERCP. After 6 months of follow-up, 100/132 (76%) patients achieved success. In multivariate analysis, the single significant predictive factor of the success of the ESWL treatment was chronic pain (p = 0.03). Patients who had chronic pain and needed opioid treatment had less chance of success than patients without chronic pain (OR 95%CI 0.31 [0.07-1.14]). We found no difference in the success rates between patients who underwent adjuvant ERCP and those who had ESWL only (p = 0.93). CONCLUSION: This study shows that the ESWL is a safe and effective treatment for patients with chronic pancreatitis and obstructive stones within the main pancreatic duct. Systematic association with therapeutic ERCP appears to provide no additional benefit and is therefore not recommended.

Critical re-evaluation of neuroglobin expression reveals conserved patterns among mammals.

Neuroglobin (Ngb) is a respiratory protein that is almost exclusively expressed in the vertebrate nervous system. Despite many years of research, the exact function and even the expression sites of Ngb are still a matter of debate. However, to investigate hypotheses surrounding the potential roles of Ngb, a detailed knowledge of its major and minor expression sites is indispensable. We have therefore evaluated Ngb expression by extensive bioinformatic analysis using publicly available transcriptome data (RNA-Seq). During mammalian brain development, we observed low embryonic expression of Ngb mRNA and an increase after birth, arguing against a role of Ngb in fetal hypoxia tolerance. In adult mouse brain, we found highest Ngb mRNA levels in the hypothalamus, where expression was up to 100-fold stronger than in cerebral cortex, cerebellum or hippocampus, as confirmed by qRT-PCR and Western blotting. High Ngb expression in the hypothalamus was found conserved in humans and other mammals. Thus, Ngb mRNA is expressed at a basal level in many mammalian brain regions, but shows distinctive regional peaks. RNA-Seq analysis further revealed only low levels of Ngb mRNA in retina and testes and no signal in standard tumor cell lines, thus raising questions concerning previous studies and functional hypotheses. In conclusion, this broad-scale expression study may point to distinct Ngb functions for high- and low-expressing cells and tissues and argues against a single, generic role of Ngb as an oxygen supplier or as an endogenous protectant in all nerve cells.

Prediction of drainage effectiveness during endoscopic stenting of malignant hilar strictures: the role of liver volume assessment.

BACKGROUND: The optimal endoscopic approach to the drainage of malignant hilar strictures remains controversial, especially with regard to the extent of desirable drainage and unilateral or bilateral stenting. OBJECTIVE: To identify useful criteria for predicting successful endoscopic drainage. DESIGN AND SETTING: Retrospective 2-center study in the greater Paris area in France. PATIENTS: A total of 107 patients who had undergone endoscopic stenting for hilar tumors Bismuth type II, III, or IV and a set of contemporaneous cross-sectional imaging data available. INTERVENTIONS: The relative volumetry of the 3 main hepatic sectors (left, right anterior, and right posterior) was assessed on CT scans. The liver volume drained was estimated and classified into 1 of 3 classes: less than 30%, 30% to 50%, and more than 50% of the total liver volume. MAIN OUTCOME MEASUREMENTS: The primary outcome was effective drainage, defined as a decrease in the bilirubin level of more than 50% at 30 days after drainage. Secondary outcomes were early cholangitis rate and survival. RESULTS: The main factor associated with drainage effectiveness was a liver volume drained of more than 50% (odds ratio 4.5, P = .001), especially in Bismuth III strictures. Intubating an atrophic sector (<30%) was useless and increased the risk of cholangitis (odds ratio 3.04, P = .01). A drainage > 50% was associated with a longer median survival (119 vs 59 days, P = .005). LIMITATIONS: Heterogeneous population and volume assessment methodology to improve in further prospective studies. CONCLUSION: Draining more than 50% of the liver volume, which frequently requires bilateral stent placement, seems to be an important predictor of drainage effectiveness in malignant, especially Bismuth III, hilar strictures. A pre-ERCP assessment of hepatic volume distribution on cross-sectional imaging may optimize endoscopic procedures.

Effects of biliary obstruction on the penetration of ciprofloxacin and cefotaxime.

OBJECTIVE: To evaluate the biliary penetration of ciprofloxacin and cefotaxime in patients with obstructed bile ducts and to determine simple predictive markers of effective biliary concentrations of these drugs. METHODS: Sixty-two patients treated with endoscopic biliary drainage were prospectively included in a nonrandomized way and received intravenous ciprofloxacin (200 mg twice daily) or cefotaxime (1 g three times a day) for more than 24 h before exploration. Blood and bile samples were collected at the time of drainage. Ciprofloxacin and cefotaxime concentrations were measured using high-performance liquid chromatography. Biliary penetration was assessed by the bile-to-plasma ratio of the concentrations of both antibiotics. RESULTS: Biliary penetration ranged from 0.06 to 42.7 for ciprofloxacin and from 0.01 to 1.14 for cefotaxime. The ratio was more than one in only 10 patients (35%) and three patients (9%) in ciprofloxacin and cefotaxime groups, respectively. Biliary concentration of the drug was more than 10 times the minimal inhibitory concentration in only 10 patients (35%) and in 12 patients (35%) in ciprofloxacin and cefotaxime groups, respectively. Serum bilirubin, alkaline phosphatase or gamma-glutamyl-transpeptidase were not good predictive markers of the biliary diffusion of the antibiotics. CONCLUSION: In patients with obstructed bile ducts, the biliary penetration of ciprofloxacin is poor and reaches effective biliary concentrations in a minority of patients. Cefotaxime biliary penetration is even poorer. No liver test can predict accurately the biliary penetration of the drugs.

[Duodenal duplication revealed by acute pancreatitis: endoscopic treatment]. / Duplication duodénale révélée par une pancréatite aiguë: traitement endoscopique.

We report the case of a 17 year old man who presented with several episodes of acute pancreatitis due to a duodenal duplication. This was successfully treated by an incision by sphincterotome during interventional duodenoscopy. The patient is symptom free without recurrence 20 months after endoscopic treatment.

Endoscopic management of post-laparoscopic cholecystectomy biliary strictures. Long-term outcome in a multicenter study.

OBJECTIVES: The aim of this retrospective study was to assess the long term results of long-lasting endoscopic stenting for benign biliary strictures related to laparoscopic cholecystectomy. Additional biological and morphological data were collected from these patients during follow-up. METHODS: Patients undergoing ERCP for post-laparoscopic cholecystectomy biliary stricture in one of the three participating centers between 1990 and December 2001 were identified. Only patients with successful endoscopic stenting were subsequently included and analyzed. Follow-up data were obtained from referring centers, general practitioners and patients or relatives. Hepatic blood tests and abdominal ultrasound were proposed to all the patients who had not undergone further treatments after stent removal. RESULTS: Eight-eight patients had undergone ERCP for benign biliary stricture related to laparoscopic cholecystectomy. Stenting failed in 19 patients. Balloon dilatation alone was used in four patients. Strictures were successfully stented in 65 patients. The mean number of stents inserted at the same time was 1.6. The mean duration of stenting was 14 months (range 1-120 months). Eighteen patients (28%) developed biliary or pancreatic symptoms during stenting. ERCP was considered satisfactory at the end of stenting (i.e. no remaining stricture or minor remaining change on ERCP) in 45 patients (69%). Twenty-two patients were lost to follow-up. Twenty-nine out of forty-three patients (67%) remained symptom-free with normal updated blood tests and abdominal ultrasound during a mean follow-up of 28 months (range 12-117 months) after stent removal. None of the patients with a normal ERCP at the end of stenting developed stricture recurrence during follow-up. Eleven patients were operated (8 with persistence of stricture, 2 for stricture recurrence up to 63 months after stent removal, 1 for pancreatitis). CONCLUSION: Based on clinical, morphological and biological criteria, a long-term success was obtained in 70% of patients with post-laparoscopic cholecystectomy benign biliary strictures, after several months of endoscopic stenting.

Reliability, cost-effectiveness, and safety of reuse of ancillary devices for ERCP.

BACKGROUND: The choice between reusable and single-use devices for ERCP depends on various medical and economic criteria. This study evaluated the reliability and the safety (risk of cross-contamination) of reusable devices. A cost analysis of the use of reusable devices also was conducted. METHODS: All patients referred for ERCP that required use of a sphincterotome or a retrieval basket were eligible for inclusion in a clinical study of 4 different devices (3 types of sphincterotome, 1 type of retrieval basket). All devices were steam sterilized. Before each use, each device was subjected to bacteriologic and virologic tests (hepatitis C virus, hepatitis B virus markers). Devices were examined before and after each procedure. The numbers of safe and efficient procedures that could be performed with each device were assessed. Three strategies were compared in a cost analysis: internal reprocessing (strategy 1), external reprocessing (strategy 2), and single-use (strategy 3). Inputs used were the results of the clinical study, hospital data for 1 year of endoscopic activity, and market prices. RESULTS: A total of 342 patients underwent the following procedures: sphincterotomy (248 patients), stent insertion (59 patients), use of basket without sphincterotomy (14 patients), and diagnostic ERCP/unsuccessful cannulation (21 patients). At the time of ERCP, 36 patients had viral or bacterial infection. Fifty instruments were used (20 single-lumen sphincterotomes, 10 double lumen sphincterotomes, 20 retrieval baskets). Overall, the median number of efficient uses per device was 10. The median number of efficient uses by each type of device was the following: single-lumen sphincterotome, 12; double-lumen sphincterotome, 8; and, retrieval baskets, 10. All virologic and bacteriologic tests for all instruments were negative. The cost-optimization analysis found that strategy 1 is cost effective (euro37,283/y) compared with strategy 2 (euro40,101/y) and especially with Strategy 3 (euro115,210/y). CONCLUSIONS: Reuse of the sphincterotomes and baskets evaluated in this study during ERCP is safe in terms of infectious hazards. Because they endure numerous uses, reusable instruments are cost effective, especially when compared with single-use accessories.

Nifedipine for prevention of post-ERCP pancreatitis: a prospective, double-blind randomized study.

BACKGROUND: Pancreatitis is the most common complication of ERCP. Calcium channel inhibitors have been shown to prevent the development of experimental pancreatitis. The aim of this randomized, placebo-controlled trial was to determine whether the calcium channel blocker nifedipine prevents post-ERCP pancreatitis. METHODS: Patients referred for ERCP were enrolled. Those being treated with a calcium channel inhibitor and those with acute or chronic pancreatitis were excluded. Nifedipine or placebo was administered orally less than 3 hours before and within 6 hours after ERCP. The main outcome measure was the number of cases of post-ERCP pancreatitis; a secondary outcome was the rate of post-ERCP pain (without pancreatitis) that persisted for 12 or more hours. RESULTS: One hundred fifty-five patients (70 women, 85 men; mean [SD] age 65.8 [18.2] years; range, 23-97 years) were enrolled and randomized to receive nifedipine (76 patients) or placebo (79 patients). The two groups were comparable. Procedures performed were retrograde diagnostic cholangiopancreatography alone (n = 33), biliary sphincterotomy (n = 31), stone extraction (n = 39), stent placement (n = 37), sphincteroplasty (n = 5), and other (n = 3). ERCP was unsuccessful in 5 patients. A single case of severe pancreatitis was observed (placebo group). The rate of post-ERCP pancreatitis was not different between groups (nifedipine, 10 patients, 13.2%; placebo, 14 patients, 17.7%; p = 0.4). The frequency of post-ERCP pain was not different between the groups. The only independent predictor of post-ERCP pancreatitis was difficult cannulation in both groups (OR = 3.78: 95% CI [1.25, 11.45]). CONCLUSION: This study failed to demonstrate a significant effect of nifedipine in the prevention of post-ERCP pancreatitis. A multicenter trial with greater statistical power would be needed to demonstrate a benefit for this drug.