Thromboembolic complications of COVID-19

© 2020, American Society of Emergency Radiology. The symptomology of patients afflicted with novel 2019 coronavirus disease (SARS-CoV-2 or COVID-19) has varied greatly, ranging from the asymptomatic state to debilitating hypoxemic respiratory failure caused by severe atypical viral pneumonia. Patients may also develop a hyper-inflammatory state that can lead to multi-organ failure. It has become increasingly apparent that, as part of the hyper-inflammatory state, COVID-19 infection increases susceptibility to systemic thromboembolic complications that can contribute to rapid clinical deterioration or demise. This article aims to review imaging features of various systemic thrombotic complications in six patients with moderate to severe disease. This case series includes examples of pulmonary embolism, stroke, right ventricular thrombosis, renal vein thrombosis, and aortic thrombosis with leg ischemia

Laparoscopic repair of incisional hernia.

A 75-year-old man developed an incisional hernia over the upper abdomen following a wedge resection of a gastric stromal tumour in 1996. This is the first published report of a successful repair of an incisional hernia via a laparoscopic intraperitoneal on-lay technique using GORE-TEX DualMesh material in Hong Kong. Compared with conventional open repair of incisional hernia, long incisions and wound tension are avoided using the laparoscopic approach. This translates into a reduced risk of wound-related complications and facilitates recovery. In selected cases, minimally invasive surgery is a safe technique for the repair of incisional hernias.published_or_final_versio

Electron interferometry with nano-gratings

We present an electron interferometer based on near-field diffraction from two nanostructure gratings. Lau fringes are observed with an imaging detector, and revivals in the fringe visibility occur as the separation between gratings is increased from 0 to 3 mm. This verifies that electron beams diffracted by nanostructures remain coherent after propagating farther than the Talbot length $z_T = 2d^2/\lambda$ = 1.2 mm, and hence is a proof of principle for the function of a Talbot-Lau interferometer for electrons. Distorted fringes due to a phase object demonstrates an application for this new type of electron interferometer.Comment: 4 pgs, 6 figure

Identifikasi Fitokimia Ekstrak Metanol Daun Paliasa (Melochiaumbellata (Houtt) Stapf) Dari Desa Renggarasi Dengan Metode Kromatografi Lapis Tipis (Klt)

Telah dilakukan penelitian mengenai Identifikasi fitokimia ekstrak metanol daun paliasa (Melochia umbellate (Houtt) stapf) dari Desa Renggarasi dengan Metode Kromatografi Lapis Tipis. Penelitian ini bertujuan untuk mengetahui senyawa sekunder yang terkandung pada daun paliasa melalui skrining fitokimia dan metode kromatografi lapis-tipis (KLT). Ekstraksi dilakukan menggunakan pelarut metanol 70% dengan cara maserasi, dan diperoleh rendemene kstrak sebanyak 0,057%. Pengujian kandungan metabolit sekunder pada ekstrak daun paliasa dilakukan secara skrining fitokimia. Hasil identifikasi positif diantaranya saponin, tanin, dan terpenoid. Selanjutnya dilakukan uji KLT dilakukan untuk melihat noda yang terbentuk pada daun paliasa dimana uji KLT ini untuk eleuen polar yaitu metanol : n-heksan (7:3) untuk noda 1 nilai Rf 0,02, noda 2 nilai Rf 0,04, noda 3 nilai Rf 0,06, dan noda 4 nilai Rf 0,1, untuk eluen non polar metanol: n-heksan (3:7) hanya terbentuk 1 noda dengan nilai Rf 0,06

Dissecting the Gaseous Halos of z~2 Damped Lyα\alpha Systems with Close Quasar Pairs

We use spectroscopy of close pairs of quasars to study diffuse gas in the circumgalactic medium (CGM) surrounding a sample of 40 Damped Lya systems (DLAs). The primary sightline in each quasar pair probes an intervening DLA in the redshift range 1.6 < z_DLA < 3.6, such that the second quasar sightline then probes Lya, CII, SiII, and CIV absorption in the CGM transverse to the DLA to projected distances $R_{\perp} < 300$ kpc. Analysis of the Lya profiles in these CGM sightlines constrains the covering fraction (f_C) of optically thick HI (having column density N_HI > 10^17.2 cm^-2) to be greater than ~30% within $R_{\perp} < 200$ kpc of DLAs. Strong SiII 1526 absorption with equivalent width W_1526 > 0.2 Ang occurs with an incidence f_C (W_1526 > 0.2 Ang) = 20(+12/-8)% within $R_{\perp}<100$ kpc, indicating that low-ionization metal absorption associated with DLAs probes material at a physical distance R_3D < 30 kpc. However, we find that strong CIV 1548 absorption is ubiquitous in these environments (f_C (W_1548 > 0.2 Ang) = 57(+12/-13)% within $R_{\perp} < 100$ kpc), and in addition exhibits a high degree of kinematic coherence on scales up to ~175 kpc. We infer that this high-ionization material arises predominantly in large, quiescent structures extending beyond the scale of the DLA host dark matter halos rather than in ongoing galactic winds. The Lya equivalent width in the DLA-CGM is anticorrelated with $R_{\perp}$ at >98% confidence, suggesting that DLAs arise close to the centers of their host halos rather than on their outskirts. Finally, the average Lya, CII and CIV equivalent widths are consistent with those measured around z~2 Lyman Break Galaxies. Assuming that DLAs trace a galaxy population with lower masses and luminosities, this finding implies that the absorption strength of cool circumgalactic material has a weak dependence on dark matter halo mass for M_h < 10^12 M_sun.Comment: Submitted to ApJ. 30 pages, 13 figures, 3 tables, 1 appendix. Uses emulateapj forma

Laparoscopic incisional hernioplasty utilising on-lay expanded polytetrafluoroethylene DualMesh: Prospective study

Objective. To evaluate the early outcomes of laparoscopic incisional hernioplasties using on-lay GORE-TEX DualMesh. Design. Prospective study. Setting. Medical centre of a regional hospital, Hong Kong. Subjects and methods. Between June 2000 and October 2001, 11 consecutive patients underwent attempted laparoscopic incisional hernioplasties at the University of Hong Kong Medical Centre. A prospective collection of perioperative data and assessment of postoperative outcomes was performed. Results. Laparoscopic incisional hernioplasty was successfully performed for 10 (91%) patients. One patient was converted to open repair because of extensive adhesions within the peritoneal cavity. The overall mean operative time was 107 minutes. Five (45%) patients were found to have more than one hernial defect after reduction of the hernial contents. Eight (73%) patients were discharged within 2 days after operation. Postoperative morbidities included wound bruising (n=4), seroma (n=2), and prolonged suture site pain (n=l). All postoperative morbidities resolved spontaneously without intervention. With a mean follow-up of 3 months, no early recurrence was detected. Conclusion. Early outcomes of laparoscopic incisional hernioplasty utilising GORE-TEX DualMesh were promising. This technique confers the advantages of minimal access surgery and allows clear identification of multiple hernial defects. Extensive adhesion, which does not allow the establishment of pneumoperitoneum, is a condition that precludes the safe performance of laparoscopic repair.published_or_final_versio

Piezoelectric and optical setup to measure an electrical field: Application to the longitudinal near-field generated by a tapered coax

We propose a new setup to measure an electrical field in one direction. This setup is made of a piezoelectric sintered lead zinconate titanate film and an optical interferometric probe. We used this setup to investigate how the shape of the extremity of a coaxial cable influences the longitudinal electrical near-field generated by it. For this application, we designed our setup to have a spatial resolution of 100 um in the direction of the electrical field. Simulations and experiments are presented

Analytic structure of radiation boundary kernels for blackhole perturbations

Exact outer boundary conditions for gravitational perturbations of the Schwarzschild metric feature integral convolution between a time-domain boundary kernel and each radiative mode of the perturbation. For both axial (Regge-Wheeler) and polar (Zerilli) perturbations, we study the Laplace transform of such kernels as an analytic function of (dimensionless) Laplace frequency. We present numerical evidence indicating that each such frequency-domain boundary kernel admits a "sum-of-poles" representation. Our work has been inspired by Alpert, Greengard, and Hagstrom's analysis of nonreflecting boundary conditions for the ordinary scalar wave equation.Comment: revtex4, 14 pages, 12 figures, 3 table

Helical Tubes in Crowded Environments

When placed in a crowded environment, a semi-flexible tube is forced to fold so as to make a more compact shape. One compact shape that often arises in nature is the tight helix, especially when the tube thickness is of comparable size to the tube length. In this paper we use an excluded volume effect to model the effects of crowding. This gives us a measure of compactness for configurations of the tube, which we use to look at structures of the semi-flexible tube that minimize the excluded volume. We focus most of our attention on the helix and which helical geometries are most compact. We found that helices of specific pitch to radius ratio 2.512 to be optimally compact. This is the same geometry that minimizes the global curvature of the curve defining the tube. We further investigate the effects of adding a bending energy or multiple tubes to begin to explore the more complete space of possible geometries a tube could form.Comment: 10 page