Shape description and matching using integral invariants on eccentricity transformed images

Matching occluded and noisy shapes is a problem frequently encountered in medical image analysis and more generally in computer vision. To keep track of changes inside the breast, for example, it is important for a computer aided detection system to establish correspondences between regions of interest. Shape transformations, computed both with integral invariants (II) and with geodesic distance, yield signatures that are invariant to isometric deformations, such as bending and articulations. Integral invariants describe the boundaries of planar shapes. However, they provide no information about where a particular feature lies on the boundary with regard to the overall shape structure. Conversely, eccentricity transforms (Ecc) can match shapes by signatures of geodesic distance histograms based on information from inside the shape; but they ignore the boundary information. We describe a method that combines the boundary signature of a shape obtained from II and structural information from the Ecc to yield results that improve on them separately

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Tensile and fracture behavior of silica fibers from the Venus flower basket (Euplectella aspergillum)

The extraordinary mechanical properties shown by many biological materials stem from their unique hierarchical structures. The spicules of the deep-sea glass sponge, Euplectella aspergillum, show layered architecture and are known to improve toughness in various loading conditions. In the present work, we conducted a systematic study on the tensile and fracture behavior of E. aspergillum\u27s spicules. Tensile tests were performed on three different gage lengths of spicules that compose anchoring structures of E. aspergillum. The cross-sectional area of each spicule was accurately measured using an x-ray microscope. The effect of gage length and varying cross-sectional area on the tensile behavior of spicules is discussed in detail. The interplay between two failure initiation sites, namely, weakest-link flaws and minimum cross-sectional area locations was observed. Weibull statistics were used to quantify the variability in the strengths of spicules as a function of their gage length. The Weibull modulus was observed to decrease with the increase in gage length. The possibility of a bimodal flaw population for a higher gage length of spicules due to the interplay between failure initiation sites is also discussed. The fractography study was utilized to understand the failure and toughening mechanisms of spicules in tensile loading. The fracture toughness of the central core was quantified from fracture surfaces using a linear elastic fracture mechanics model. The present study shows that the failure of spicules initiates in the outer layers and proceeds progressively to the center. The layers surrounding the central core of the spicule resist the crack propagation and increase its toughness

Improving Outcome of Treatment of Kala-Azar by Supplementation of Amphotericin B with Physiologic Saline and Potassium Chloride

Complications of amphotericin B limit its wide application in the treatment of patients with kala-azar. This study was undertaken with an aim to minimize anti-renal complications and severe rigor in course of treatment with this drug. Parasitologically confirmed kala-azar cases (n = 230) were randomized equally into two groups: a control group received amphotericin B only at a dose of 1 mg/kg of body weight/day for 20 days and a patient (test) group received 500 mL of physiologic saline and 30 mL (60 meq/L) of KC1 with amphotericin B. We observed a significantly lower increase in serum creatinine levels (P = 0.0001) and a lower incidence of severe rigor and fever (P = 0.0165) in the test group than in the control group. However, the ultimate cure rate was not significantly different (P = 0.5637) between two groups after 12 months of follow-up. Relapses occurred after even after six months in both groups. Persons with relapses were treated with 25 infusions of amphotericin B and cured. Supplementation of amphotericin B with 500 mL of physiologic saline and 30 mL (60 meq/L) of KCl during treatment could help prevent an increase in serum creatinine levels and severe rigor and would make the treatment of kala-azar with amphotericin B easier

Effect of Emerged Coastal Vegetation on Wave Attenuation Using Open Source CFD Tool: REEF3D

Coastal vegetation is a soft solution for protecting the coast from the action of waves by attenuating the wave height and reducing the energy of the waves. Effect of wave height attenuation as a result of the presence of emerged coastal vegetation is studied numerically by resolving the Reynolds-averaged Navier–Stokes (RANS) equations. A three-dimensional numerical wave tank model is simulated using an open source computational fluid dynamics (CFD) software REEF3D, and wave attenuation due to emerged coastal vegetation is determined. An artificial, rigid, emerged vegetation for a length of 2 m is developed in a numerical wave tank of REEF3D. The model is tested for regular waves of height 0.08, 0.12, and 0.16 m and wave periods of 1.8 and 2 s in a water depth of 0.40 and 0.45 m. The wave heights are measured at different locations along the vegetation meadow at 0.5 m intervals. The devolved numerical model is corroborated by comparing the obtained numerical results with the experimental results as reported by John et al. (Experimental investigation of wave attenuation through artificial vegetation meadow, ISH—HYDRO, [1]). The numerically obtained results are concurrent with the experimental results