Photo- and exchange-field controlled line-type resonant peaks and enhanced spin and valley polarizations in a magnetic WSe2 junction

Existing resonant tunneling modes in the shape of line-type resonances can improve the transport properties of the junction. Motivated by the unique structural properties of monolayer WSe2 e.g. significant spin-orbit coupling (SOC) and large direct bandgap, the transport properties of a normal/ferromagnetic/normal (NFN) WSe2 junction with large incident angles in the presence of exchange field (h), off-resonance light (∆Ω) and gate voltage (U) is studied. In a certain interval of U, the transmission shows a gap with optically controllable width, while outside it, the spin and valley resolved transmissions have an oscillatory behavior with respect to U. By applying ∆Ω (h), an optically (electrically) switchable perfect spin and valley polarizations at all angles of incidence have been found. For large incident angles, the transmission resonances change to spin-valley-dependent separated ideal line-type resonant peaks with respect to U, resulting in switchable perfect spin and valley polarizations, simultaneously. Furthermore, even in the absence of U, applying h or ∆Ω at large incident angles can give some spin-valley dependent ideal transmission peaks, making h or ∆Ω a transmission valve capable of giving a switchable fully spinvalley filtering effect. These findings suggest some alternate methods for providing high-efficiency spin and valley filtering devices based on WSe2.

Effectiveness of line type and cross type piezoelectric patches on active vibration control of a flexible rectangular plate

In the present work, vibration control of a simply supported plate with line type and cross type piezoelectric (PZT) patches are investigated with and without actuation voltage. The plate is modeled under the assumption of Kirchhoff’s Plate theory. The mass of PZT patches remain constant in all cases. In case of actuation, applied voltage considered are 1, 2 and 3 mV. The external excitation to the plate is in the form of harmonically varying point load of 1 mN. It is noticed that cross type PZT patch is more effective in deflection suppression of plate than that of line type PZT patch at 3 mV of actuation at patch thickness of 0.75 μm. Suppression of central deflection of plate for line type and cross type PZT patches are obtained in different frequency bands of (175–185 Hz) and (870–880 Hz) respectively.

769. Risk Factors of Central Line-associated Bloodstream Infection in an Academic Medical Center

Background Central line-associated bloodstream infections (CLABSI) are one of the leading healthcare-acquired infections (HAI) with significant morbidity and mortality. We aimed to identify risk factors of CLABSI at an academic medical center to determine high-risk populations and target interventions. Methods This is an observational retrospective cohort study at William P. Clements Jr. University Hospital from January 1, 2017 to December 31, 2020. Retrospective chart review was conducted to identify demographics and co-morbidities of hospitalized patients diagnosed with CLABSI as defined by National Healthcare Safety Network (NHSN). Infections due to mucosal barrier injuries were excluded. Means were compared using independent-samples T-test and proportions were compared using chi-square. Results Ninety-three CLABSI events were identified with an increase in the standardized infection ratio from 0.38 in 2017 to 0.74 in 2020 (Figure 1). Bacterial organisms were identified in 71 (76%) cases while fungal organisms were identified in 22 (24%) (Table 2). There was no significant difference in the timing of CLABSI after line insertion (p=0.09) or organism identified (p=0.61) in PICC lines (n=33, 34%) vs all other central lines (n=60, 67%). When comparing immunocompromised patients with CLABSI (n=47, 51%) vs non-immunocompromised (n=46, 50%), there was a significant difference in the indication for line (chemotherapy), but no difference was seen in the number of line days prior to event (p=0.57), line type (p=0.17), or organism identified (p=0.94). Of all CLABSI, 46% (n=43) were in the intensive care unit (ICU) with significantly more Candida species (p=0.018) identified compared to non-ICU patients with CLABSI (n= 50, 54%). Figure 1. CLABSI Rate and SIR from 2017 to 2020 by Quarter Conclusion Candida species were more likely to be found in ICU patients with CLABSI as compared to non-ICU counterparts with further investigation in the ICU population revealing lack of flushing after administration of total parenteral nutrition. Otherwise, this observational cohort of CLABSI events did not identify any difference in immunosuppression status or line type. Given this information, infection prevention efforts will continue to be directed towards proper central line maintenance and removal when no longer indicated. Disclosures All Authors: No reported disclosures

Deep Learning-Based Method to Recognize Line Objects and Flow Arrows from Image-Format Piping and Instrumentation Diagrams for Digitization

As part of research on technology for automatic conversion of image-format piping and instrumentation diagram (P&ID) into digital P&ID, the present study proposes a method for recognizing various types of lines and flow arrows in image-format P&ID. The proposed method consists of three steps. In the first step of preprocessing, the outer border and title box in the diagram are removed. In the second step of detection, continuous lines are detected, and then line signs and flow arrows indicating the flow direction are detected. In the third step of post-processing, using the results of line sign detection, continuous lines that require changing of the line type are determined, and the line types are adjusted accordingly. Then, the recognized lines are merged with flow arrows. For verification of the proposed method, a prototype system was used to conduct an experiment of line recognition. For the nine test P&IDs, the average precision and recall were 96.14% and 89.59%, respectively, showing high recognition performance.